WO1996038182A1

WO1996038182A1 - Insulin suppression test with igf

Info

Publication number: WO1996038182A1
Application number: PCT/US1996/007169
Authority: WO
Inventors: Eli Ipp
Original assignee: Harbor-Ucla Research And Education Institute
Priority date: 1995-06-02
Filing date: 1996-05-16
Publication date: 1996-12-05
Also published as: AU5863396A

Abstract

The present invention provides a method for using IGF for diagnosis or exclusion of inappropriate insulin regulation in mammals. Also provided are kits and pharmaceutical compositions for performing such diagnosis or exclusion.

Description

INSULIN SUPPRESSION TEST WITH IGF

Field of the Invention This invention relates to the use of insulin-like growth factor (IGF), for example, insulin-like growth factor I (IGF-I) or insulin-like growth factor II (IGF-II), as a tool for diagnosis or exclusion of inappropriate insulin regulation in mammals. This invention, thus, relates to methods for diagnosis or exclusion of inappropriate insulin regulation and kits for such use as, for example, in the diagnosis or exclusion of insulinoma, a rare form of insulin secreting tumor in the pancreas.

Background of the Invention The insulin-like growth factors have molecular weights of about 7,500 daltons. They possess A and B domains that are highly homologous to the corresponding domains of proinsulin. The A and B domains are connected to each other by a C domain. A carboxy terminal extension, the D domain, is present in IGF but is not found in proinsulin. The designation "insulin-like growth factor" was chosen to express the insulin-like effects and the insulin-like structure of the IGF. Both IGF-I and IGF-II are single-chain polypeptides, each with 3 disulfide bridges and has a sequence identity of about 49% and 47%, respectively, to human insulin A chain and B chain. IGF-I is a 70 amino acid peptide, and IGF-II is a 67 amino acid peptide, as described in Rinderknecht, J. Biol Chem., (1978) 253:2769; and Rinderknecht, FEBS Letters, (1978) 89:283. IGF-I and IGF-II have a 62% structural homology to each other. Both have been isolated from human serum and have been found capable of acting as mitogens on a number of different cell types, as described in EP 0 128 733. Like insulin, IGF stimulates phosphorylation of specific tyrosine residues within the cytoplasmic domain of the receptors to which it binds, as described in WO 93/98826.

Low blood glucose concentration, a condition known as hypoglycemia, is a relatively common cause of referral of patients to the accident and emergency departments of hospitals. The diagnosis of hypoglycemia is suspected from one or more of the adrenergic symptoms of sweating, nervousness, tremulousness, faintness, palpitations, and sometimes hunger, and the central nervous system (CNS) symptoms of confusion, inappropriate behavior, visual disturbances, stupor, coma, and seizures. The approach to diagnosis depends on whether the patient presents with unexplained CNS manifestations or unexplained adrenergic symptoms. In either case, the diagnosis requires evidence that the symptoms occur in association with an abnormally low plasma glucose level and are corrected by raising the plasma glucose, as described in THE MERCK MANUAL, 16th ed., Berkow ed. (Rahway, N.J. 1992).

Very often hypoglycemia is induced in patients by the treating physicians or their staff, for example, in the course of administration of a diagnostic test or a therapeutic drug, as described in Marks and Teale, Baillieres Clinical Endocrinology and Metabolism (1993), 7(3): 705-29. As further described in the same review article, occasionally, hypoglycemia can be the result of hyperinsulinism due to abnormal β-cell function, which is an uncommon but important cause of hypoglycemia. Patients with the insulin-secreting pancreatic tumors, insulinomas and islet cell carcinomas, usually have increased proinsulin and C-peptide levels that parallel insulin levels, in addition to having low blood glucose levels. Other causes of hypoglycemia include endocrinopathies of various kinds, sepsis, congestive heart failure, hepatic and renal insufficiency, diverse inborn errors of metabolism, exogenous toxins such as alcohol, and insulin overdose.

Insulinoma is a rare form of tumor in the pancreas characterized by autonomous, non-suppressible insulin secretion and hypoglycemia. Insulinomas are diagnosed in approximately 1000 new patients in the U.S. each year. Two biochemical tests are currently being used by the medical community for the diagnosis of insulinoma: a 72-hour fasting test, and a continuous insulin infusion test. The 72-hour fasting test involves repeated measures of blood glucose and insulin over a 72-hour period of fasting. In a healthy person, blood glucose concentration after fasting would fall, as compared to the pre-fasting stage, but would still remain within normal limits, while insulin would be near or below the detection limit of currently available commercial assays, such as insulin RIA- assays. This 72-hour fasting test is reliable though cumbersome, and patients dislike it, making it impractical.

The continuos insulin infusion test for the diagnosis of insulinoma is performed as described in Ipp et al, J. Clin. Endoc. Metab. (1990), 70:711. In this test, insulin is infused at a rate of 40 μU/kg/h which, in a normal individual, is sufficient to suppress endogenous secretion of insulin, while blood glucose remains near normal. In this test, the level of C-peptide, a cleavage product of proinsulin is measured as a surrogate marker. Insulin has a half-life of 5-6 minutes, while C-peptide has a half-life of 20-30 minutes. In a normal individual, therefore, the C-peptide level would decrease during this test. In contrast, in patients with insulinomas, endogenous secretion of insulin would not be affected, hence, the C-peptide level would remain relatively high. To perform this 3- hour continuous dosage insulin infusion test, one-half day of hospitalization, an intravenous line, and an infusion pump are required. In some instances, the test may be inconclusive and a 72-hour fasting test must also be performed.

Insulin-like growth factor I (IGF-I) has been shown to suppress endogenous insulin secretion in healthy people very consistently and within a very short perod of time. IGF-I doses capable of suppressing endogenous insulin secretion do not induce hypoglycemia. In vitro data from β-cell cultures are in line with the clinical findings: production of insulin by the β-cells can be blocked by adding IGF-I to the culture medium.

It would be advantageous, therefore, if a simpler, less expensive and less cumbersome test can be devised for the diagnosis or exclusion of inappropriate insulin regulation. Summary of the Invention

It is, therefore, an object of the present invention to provide a quick, easy-to- administer test for diagnosis or exclusion of inappropriate insulin regulation in mammals, for example, humans.

It is another object of the invention to provide methods, kits and pharmaceutical compositions for such tests for diagnosing or excluding inappropriate insulin regulation. In accordance thereto, there is provided herein a method for diagnosis or exclusion of inappropriate insulin regulation in a mammal, for example, human, comprising administering thereto a diagnostic amount of insulin-like growth factor and monitoring its effect on the mammal. In accordance to another object of the present invention, there is provided a method as above, where the IGF is IGF-I or IGF-II.

In accordance to a further object of the present invention, there is provided a method as above, where monitoring the effect of IGF involves measuring at least one of blood glucose concentration, insulin level, C-peptide level, and IGFBP-1 level, before and after administration of IGF.

In accordance to still another object of the present invention, there is provided a kit for diagnosis or exclusion of inappropriate insulin regulation, the kit containing IGF and a pharmaceutically acceptable carrier. In accordance to a further object of the present invention, there is provided a kit as above, where the IGF is either IGF-I or IGF-II.

In accordance to yet a further object of the present invention, there is provided a kit as above, where the IGF and the pharmaceutically acceptable carrier is contained in a prefilled container such as a prefilled syringe. In accordance to yet another object of the present invention, there is provided a method as above, where the diagnostic amount of IGF-I, in micrograms per kilogram, is in a range selected from the group consisting of: 25-45, 30-50, 40-55, 35-65, 60-80, 75- 90, 70-95, 85-100, 105-120, and 110-130.

In accordance to still another object of the present invention, there is provided a pharmaceutical composition comprising IGF and a pharmaceutically acceptable carrier, wherein the IGF is in a concentration range selected from the ranges, in microgram/ml, consisting of 2-5, 3-8, 4-9, 6-10, 7-30, 15-25, 20-50, 35-45, 40-60, and 55-70. Further objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

Detailed Description of the Preferred Embodiments The invention described herein draws on previously published work and, at times, on pending patent applications. By way of example, such work consists of scientific papers, abstracts, published or issued patents, and published patent applications. All published work cited herein are hereby incorporated by reference. The inventor herein has discovered a safe, inexpensive, and easy to administer test for the diagnosis or exclusion of inappropriate msulin regulation. The inventor has discovered that IGF, for example, IGF-I or IGF-II, can be administered as a diagnostic to patients complaining of symptoms of hypoglycemia such as dizziness, headaches, blurred vision, tremendous hunger, etc., and inappropriate insulin regulation can be diagnosed or ruled out based upon a comparison of the patient's blood glucose concentration, insulin level, C-peptide level, or IGFBP-1 level before and after administration of IGF.

Thus, for example, if a healthy individual is administered a dose of IGF, his or her plasma insulin level is expected to go down after such administration, regardless of whether the individual is fasting or not. In contrast, if the individual has insulinoma, his or her insulin level is not suppressible. Administration of IGF, therefore, will not lower plasma insulin level. Accordingly, maintenance of a high insulin level after administration of IGF would indicate the presence of inappropriate insulin regulation in that individual. On the other hand, if plasma insulin level goes down after administration of IGF, this result would rule out inappropriate insulin regulation as a cause of hypoglycemia in that individual.

This invention, therefore, provides a method for diagnosis or exclusion as described above, a kit and a pharmaceutical composition for effecting this method, the kit containing IGF and a pharmaceutically acceptable carrier.

The term "inappropriate insulin regulation," as used herein, encompasses conditions in which there are unphysiologically or inappropriately high insulin levels. One such example is patients with insulinoma, when there is non-suppressible insulin hypersecretion and the patients present with signs and symptoms of hypoglycemia. Insulin regulation in the patient is appropriate, for example, when plasma concentration of insulin and C-peptide fall during fasting or when insulin level can be lowered by administration of IGF. In patients with insulinoma, for example, inappropriate insulin regulation can be demonstrated by unphysiologically high insulin and C-peptide levels that do not fall during fasting or high insulin levels that cannot be suppressed by IGF administration.

The term "administering" includes administration by a variety of methods as conventionally known in the art suitable to attain the desired result, including for example, subcutaneously, topically, orally, intramuscularly, and intraperitoneally. Preferably, IGF herein is administered subcutaneously in a single dose per test. The dose to administer is from about 40 μg/kg to about 100 μg/kg, which may be administered more than once, if needed. For administration of IGF, one may incorporate or encapsulate IGF in a suitable carrier. A thorough discussion of pharmaceutically acceptable excipients is available in REMINGTON'S PHARMACEUTICAL SCIENCES, 18th ed., 1990 (Mack Pub. Co., Easton, PA).

A "diagnostic amount" is that amount that is effective for production of a desired diagnostic result which, in the case of the present invention, is testing whether insulin secretion can be suppressed in a patient. The amount of IGF to be administered as a diagnostic amount varies depending upon the health and physical condition of the individual to be treated, the formulation, the attending physician's assessment of the medical situation, the age, size, and condition of the subject, the nature and severity of the disorder to be treated, and other relevant factors. It is expected that the amount will fall within a relatively broad range that can be determined through routine trials by a qualified physician or veterinarian. Thus, for example, a diagnostic amount for an insulin suppression test can be in the range of about 40 μg/kg to 100 μg/kg, preferably about 55 μg/kg to 95 μg/kg, more preferably about 65 μg/kg to 90 μg/kg, most preferably about 80 μg/kg. In general terms, an effective diagnostic amount of IGF will range from about 25 μg/kg - 45 μg/kg, 30 μg/kg - 50 μg/kg, 40 μg/kg - 55 μg/kg, 35 μg kg - 65 μg/kg, 60 μg/kg - 80 μg/kg, 75 μg/kg - 90 μg/kg, 70 μg/kg - 95 μg/kg, 85 μg/kg - 100 μg/kg, 105 μg/kg - 120 μg/kg, and 110 μg/kg - 130 μg/kg.

The term "insulin-like growth factor" or "IGF" is used to encompass both IGF-I and IGF-II, preferably, IGF-L in its substantially purified, native, recombinantly produced, or chemically synthesized forms. This term includes non-native IGF polypeptides that are biologically active fragments, analogs, muteins, including C-terminal deletion muteins, and derivatives thereof that retain IGF activity and/or ability to bind the IGF receptors, as described in, for example, EP 0 135 094, WO 85/00831, U.S. Patent No. 4,738,921, WO 92/04363, U.S. Patent No. 5,158,875, EP 0 123 228, and EP 0 128 733. The non-native IGF polypeptides are suitable for use herein to the extent that they produce the same diagnostic effect described herein as the native, or recombinantly produced, or synthetic IGF.

An analog of IGF or an analog of an IGF fragment includes native IGF that has been modified by one or more amino acid insertion, deletion, or substitution that does not substantially affect its properties. For example, the analog can include conservative amino acid substitutions. An IGF analog also includes peptides having one or more peptide mimics ("peptoids"), such as those described in WO 91/04282. An IGF mutein is polypeptide variant with one or more amino acids altered to produce a desired characteristic, such as to replace a cysteine residue with a non-disulfide bond forming amino acid. Muteins, analogs and derivatives may be generated using conventional techniques. For example, PCR mutagenesis can be used. An example of a PCR technique is described in WO 92/22653. Another method for making analogs, muteins, and derivatives, is cassette mutagenesis based on the technique described by Wells, Gene, (1985) 34:315. Description of IGF analogs, derivatives, or muteins and their methods of preparation can be found in the literature, for example, Ballard et al. (1987), Biochem. Biophys. Res. Commun. J 49:39S-404; Bayne etal. (1988), J. Biol. Chem. 263:6233- 6239; Cascieri etal. (1988), Endocrinol. 723:373-381; Clemmons etal (1990), J. Biol. Chem. 265: 12210-16; and Cara etal. (1990), J. Biol. Chem. 265: 17820-17825.

IGF, for use herein, can be made by a variety of known techniques. Thus, IGF can be isolated and purified from serum or plasma or produced by recombinant DNA techniques in microbial hosts such as bacteria or yeast or in cell cultures such as insect cell or animal cell cultures, or chemically synthesized in accordance with conventional techniques. For example, IGF can be isolated in small quantities from large volumes of plasma or serum, as described in Phillips, NewEngl. J. Med., (1980) 302:371-380. IGF can also be synthesized by the solid phase method as described in Li, PNAS (USA), (1983) 50:2216-2220. In this method, the polypeptide sequence for IGF-I can be assembled by coupling the amino acid residues.

The term "hypoglycemia" refers to a syndrome characterized by symptoms of sympathetic nervous system stimulation or of CNS dysfunction that are provoked by an abnormally low plasma glucose level which has many potential causes, as defined in THE MERCK MANUAL, 16th edition, 1992, ed. Berkow et al, (Merck Research Laboratories, Rahway, N.J.).

The term "pharmaceutically acceptable carrier" refers to a carrier suitable for administration of IGF into mammals, including humans, and refers to any pharmaceutical carrier that does not itself induce the production of antibodies harmful to the individual receiving the composition, and that may be administered without undue toxicity. Suitable carriers may be large, slowly metabolized macromolecules such as proteins, polysaccharides, polylactic acids, polyglycolic acids, polymeric amino acids, amino acid copolymers, and inactive virus particles. Such carriers are well known to those of ordinary skill in the art. Pharmaceutically acceptable salts can be included therein, for example, mineral acid salts such as hydrochlorides, hydrobromides, phosphates, sulfates, and the like; and the salts of organic acids such as acetates, propionates, malonates, benzoates, and the like. A thorough discussion of pharmaceutically acceptable excipients is available in REMINGTON'S PHARMACEUTICAL SCIENCES (Mack Pub. Co., N.J. 1991). Pharmaceutically acceptable carriers may contain liquids such as water, saline, glycerol and ethanol. Additionally, auxiliary substances, such as wetting or emulsifying agents, pH buffering substances, and the like, may be present in such vehicles. Preferably, the diagnostic compositions are prepared as injectables, either as liquid solutions or suspensions; solid forms suitable for solution in, or suspension in, liquid vehicles prior to injection may also be prepared.

The term "kit" refers to a package containing the specified material or materials and includes printed instructions for use of such materials. For example, the kit of the present invention contains a sufficient amount of IGF for administering a diagnostic amount to a patient. The kit may also contain, for example, reagents and tools, such as a prefilled syringes, for administering the IGF.

The term "instructions" refers to printed instructions which may be written or printed on paper or other media, or committed to electronic media such as magnetic tape, computer-readable disks or tape, CD-ROM, and the like.

The IGF herein can generally be expressed in any unicellular organism, including, for example, yeast cells, bacterial, insect, and mammalian cells. Thus, IGF can be made by conventional recombinant DNA techniques, as described in Biochem. andBiophys.

Res. Comm., (1990) 769:832-839 (IGF π) and Cell Regulation, (1990) 7:197-213, (IGF H), and Biotechnology News, (1983) 3: 1-3 (IGF-I and II). For example, IGF can be produced in Ecoli as a fusion protein with the trpE gene under the control of a modified tryptophan operon, as described in U.S. Patent No. 4,738,921. Alternatively, IGF can be synthesized in E. coli under the control of the Vesicular Stomatitis Virus (VSV) promoter and protector sequences, as described in EP 478 333. TheE. coli expression systems used for expression herein can be modified, as described in U.S. Patent No. 5,158,875, to include a modified positively charged leader sequence to enable proper folding of the IGF protein.

Moreover, IGF can be produced in methylotrophic yeast transformants with the

IGF coding sequence linked to a signal sequence which direct secretion and proteolytic processing of the protein product. The signal sequence suitable herein includes the S. cerevisiae alpha mating factor pre-pro sequence in protease deficient P. pastoris strains, as described in WO 92/04363.

DNA constructs for production of IGF-II can be made and expressed inTi. coli as described in WO 89/03423. Synthesis of recombinant IGF-II can also be achieved by following the protocol described in EP 0434 605, which relates to the production of recombinant IGF-II with a covalently attached foreign moiety and lacking the N-terminal attached methionine.

IGF can also be made in yeast, as described in EP 0 123 228 and U.S. Serial No.

06/922,199. Another method of producing IGF using recombinant DNA techniques that is suitable herein is described in Biotechnology News, (1983) 70:1-3. IGF-I or IGF-II coding sequences can be inserted into viral or circular plasmid DNA vectors to form hybrid vectors, and the resulting hybrid vectors can be used to transform host microorganisms such as bacteria or yeast cells. The transformed microorganisms can be grown under appropriate nutrient conditions to express IGF, as described in EP 0 135 094.

In another context, human IGF-I and IGF-II can be expressed and secreted using a leader sequence that contains a portion of the yeast α-factor signal sequence, as described in EP 0 128 733.

Yeast cells in which IGF-I can be expressed include Saccharomyces cerevisiae (Hinnen, PNAS (USA), (1978) 75:1929; Ito, J. Bacteriol., (1983) 153: 163;

Saccharomyces carlsbergeneis; Candida albicans, Kurtz, Mol. Cell. Biol, (1986) 6:142; Candida maltosa, Kunze, J. Basic Microbiol, (1985) 25:141; Hansenula polymorpha (Gleeson, J. Gen. Microbiol, (1986) 32:3459; Roggenkamp, Mol Gen. Genet., (1986) 202:302; Kluyveromyce fragϊlis, Das, J. Bacteriol, (1984) 75ό':l 165; Kluyveromyces lactis, De Louvencourt, J. Bacteriol, (1983) 154:737; Van den Berg, Bio/Technology, (1990) 8:135; Pichia guillerimondii, Kunze, J. Basic Microbiol, (1985) 25:141; Pichia pastoris, Cτegg,Mol Cell Biol, (1985) 5:3376; U.S. Patent Nos. 4,837,148 and 4,929,555; Schizosaccharomyces pombe, Beach, Nature, (1981) 300:706; and Yarrowia lipolytica, Davidow, Curr. Genet., (1985) 70:380471; Gaillardin, Curr. Genet., (1985) 70:49; Neurospora crassa, Case, PNAS (USA), (1979) 76:5259; and filamentous fungi such as, Neurospora, Penici/lium, Tolypocladium, WO 91/00357, and Aspergillus hosts such as A. nidulans, Ballance, Biochem. Biophys. Res. Comm., (1983) 772:284; Tilburn, Gene, (1983) 26:205, Yelton, PNAS (USA), (1984) 1981:1470, and A Niger, Kelly, EMBOJ., (1985) 4:475-479. IGF herein can be expressed in bacterial cells including, for example,

Streptococcus spp., and Streptomyces spp., eubacteria, such as Gram-negative or Gram- positive organisms, for example, E. coli, Bacilli such as B. subtilis, Pseudomonas species such as P. aeruginosa, Salmonella typhimurium, or Serratia marcescans.

IGF herein can further be expressed in insect cells with a baculovirus expression system, including, for example, numerous baculoviral strains and variants and corresponding permissive insect host cells from hosts such as Spodopterafrugiperda (caterpillar), Aedes aegypti (mosquito), Aedes albopictus (mosquito), Drosophila melanogaster (fruitfly), and Bombyx mori host cells, as described in Luckow, Bio/Technology, (1988) 6:47; Miller et al, in GENETIC ENGINEERING (Setlow, J.K. et al eds.), Vol. 8 (Plenum Publishing, 1986), pp. 277-279, and Maeda et al, Nature, (1985) 375:592-594. A variety of such viral strains are publicly available, e.g., the LI variant of Autographa californica NPV and the Bm5 strain of Bombyx mori NPV. Such viruses may be used as the virus for transfection of host cells such as Spodoptera frugiperda cells. Many baculovirus genes may be employed to advantage in a baculovirus expression system. These include immediate-early (α), delayed-early (β), late (γ), or very late (V), according to the phase of the viral infection during which they are expressed. The expression of these genes occurs sequentially, probably as the result of a "cascade" mechanism of transcriptional regulation. One relatively well defined component of this regulatory cascade is IEI, a preferred immediate-early gene of Autographo californica nuclear polyhedrosis virus (AcMNPV). IEI encodes a product that stimulates the transcnption of several genes of the delayed-early class, including the preferred 39K gene, as described in Guarino and Summers, J. Virol. (1986) 57:563-571 andJ. Virol. (1987) 67:2091-2099 as well as late genes, as described in Guanno and Summers, Virol. (1988) 762:444-451.

The polyhedrin gene is classified as a very late gene. Therefore, transcription from the polyhedrin promoter requires the previous expression of an unknown, but probably large number of other viral and cellular gene products. Because of this delayed expression of the polyhedrin promoter, state-of-the-art BEVs, such as the exemplary BEV system described by Smith and Summers in, for example, U.S. Pat. No., 4,745,051 will express foreign genes only as a result of gene expression from the rest of the viral genome, and only after the viral infection is well underway. This represents a limitation to the use of existing BEVs. The ability of the host cell to process newly synthesized proteins decreases as the baculovirus infection progresses. Thus, gene expression from the polyhedrin promoter occurs at a time when the host cell's ability to process newly synthesized proteins is potentially diminished for certain proteins. As a consequence, the expression of secretory glycoproteins in BEV systems is complicated due to incomplete secretion of the cloned gene product, thereby trapping the cloned gene product within the cell in an incompletely processed form. IGF can also be produced in mammalian host cells including, for example, expression in monkey cells, as described in Reyes., Nature, (1982) 297:598, cultured mouse and rabbit cells, mouse NIH-3T3 cells many immortalized cell lines available from the American Type Culture Collection (ATCC), including, for example, Chinese hamster ovary (CHO) cells, as described in Urlaub, PNAS (USA), (1980) 77:4216, HeLa cells, baby hamster kidney (BHK) cells, monkey kidney cells (COS), human hepatocellular carcinoma cells (e.g., Hep G2), human embryonic cell line as described in Grisham, J. Gen. Virol, (1977) 36:59, mouse sertoli cells as described in Mather, Biol Reprod., (1980) 23:243, African green monkey cells, canine kidney cells, buffalo rat liver cells, human lung cells, human liver cells, and mouse mammary tumor cells, among others. For the purpose of the present invention, IGF is administered to a mammal, such as a human patient, who is in need of a diagnosis or exclusion of inappropriate insulin regulation. Such patients generally present with signs and symptoms typical of hypoglycemia. In the practice of the present method of diagnosis or exclusion, the patient may either be fasting or non-fasting. A blood sample is taken from the patient before administration of IGF so that a baseline level of blood glucose, insulin activity and/or C- peptide level and IGFBP-1 level can be determined. A diagnostic dose of IGF is then administered to the patient, preferably, subcutaneously, in a single dose. The dose can be established by routine testing so as to produce a diagnostic effect to differentiate an individual with normal insulin regulation from inappropriate insulin regulation. Such a dose can be selected from a range, in micrograms per kilogram of patient weight, of about from 25-130, preferably 30-100, more preferably 50-90, and most preferably 60-80. Alternatively, the ranges can be, in micrograms per kilogram, from about 25-45, 30-50, 40-55, 35-65, 75-90, 70-95, 85-100, 105-120, or 110-130.

In a preferred embodiment, the IGF is given in a volume, in microliters, in a range of about 100-200, 150-250, 200-300, 250-350, 300-400, 350-450, 400-500, 450-550 or 500-600. Preferably, the injected volume is less than 1 ml, more preferably, less than 0.75 ml, and most preferably, about 0.5 ml.

Thus, the IGF to be administered can be provided with a pharmaceutically acceptable carrier suitable for injection subcutaneously. This IGF can be provided in a kit format, preferably, in the form of a prefilled syringe. The concentration of IGF in the kit can be a concentration appropriate for direct injection. This concentration can be easily determined by conventional testing. For example, the IGF concentration in a range, selected from a group of ranges, in microgram/ml, consisting of 2-5, 3-8, 4-9, 6-10, 7-30,

15-25, 20-50, 35-45, 40-60, and 55-70. Accordingly, a pharmaceutical composition containing IGF and a pharmaceutically acceptable carrier can be made to contain the above-mentioned concentration ranges in a volume range as described above.

After administration of the IGF to the individual for diagnostic purposes, a certain amount of time is permitted to elapse to allow the IGF to exert its effect. This amount of time can be adjusted depending on the dose of the IGF given, the health of the patient, and other factors conventionally taken into consideration. For example, this amount of time can be anywhere within the range of half an hour to four hours. In one embodiment of the invention, this time can be about half an hour, preferably, about one hour, more preferably, about two hours, most preferably, about three hours. After the desired amount of time has elapsed, another blood sample can be drawn from the patient and the plasma levels of insulin, glucose, and/or C peptide, and or IGFBP-1 can again be determined.

A diagnosis of inappropriate insulin regulation can be made when the level of insulin activity remains inappropriately high after IGF administration. Inappropriate insulin regulation can be excluded in instances where insulin activity drops in accordance to that of a normal individual after IGF administration.

The following example is given by way of illustration to facilitate a better understanding of the invention and is not intended to limit the invention in any way.

Example 1 Procedure for Diagnosis or Exclusion of Inappropriate Insulin Regulation The test for inappropriate insulin regulation in accordance with the present invention can be administered in accordance with the following protocol:

This visit takes place in the morning. The patient must be over-night fasted (no food intake smce 9:00 p.m. of the preceding day, calory-free drinks are allowed). The patient remain in a chair throughout the test and no food intake is allowed until after the last blood sample is drawn. Reading, watching TV etc., and drinking of calory-free fluids is allowed. Patients may go to the bathroom if necessary.

1. A short catheter is placed in an antecubital vein and left in position throughout the test. Baseline venous blood is drawn for measurement of blood glucose, insulin, C-peptide and serum IGF-I (free and total) between 7:00 a.m. and 9:00 a.m.

2. Blood pressure and heart rate are recorded in the sitting position prior to study drug injection and at 1, 2, and 3 hours.

3. A subcutaneous injection of IGF is administered in the abdomen within 15 minutes after the baseline blood draw.

4. Follow-up blood samples for blood glucose, insulin, C-peptide, and IGF-I (total and free) are drawn at exactly 30 minutes, 45 minutes, 60 minutes, 120 minutes, and 180 minutes after the study drug was injected.

Claims

WHAT IS CLAIMED IS:

1. A method for diagnosis or exclusion of inappropriate insulin regulation in a mammal, comprising administering thereto a diagnostic amount of insulin-like growth factor and monitoring its effect in the mammal.

2. The method of claim 1, wherein the IGF is IGF-I or IGF-II.

3. The method of claim 1, wherein the monitoring of the effect of IGF comprises comparing insulin activity in the mammal before and after the administration of IGF.

4. The method of claim 1, wherein the monitoring of the effect of IGF further comprises comparing level of at least one selected from the group consisting of: blood glucose, insulin, C-peptide, and IGFBP-1 in the mammal before and after IGF administration.

5. The method of claim 1, wherein the monitoring of the effect of IGF administration is performed before the administration of IGF and after the administration of IGF at a time selected from the group consisting of approximately 1/2 hour, 1 hour, 2 hours, 3 hours, and 4 hours after administering the IGF.

6. The method of claim 1, wherein IGF-I is administered subcutaneously.

7. The method of claim 1, wherein the diagnostic amount of IGF-I, in μg/kg is in a range selected from the group of ranges consisting of about 25-45, 30-50, 40-55, 35-65, 60-80, 75-90, 70-95, 85-100, 105-120, and 110-130.

8. A kit for diagnosis or exclusion of inappropriate insulin regulation comprising IGF and a pharmaceutically acceptable carrier, wherein the IGF is at a concentration that is suitable for direct injection for diagnosis or exclusion of inappropriate insulin regulation.

9. The kit of claim 8, further comprising a prefilled syringe containing the IGF.

10. The kit of claim 8, wherein the IGF is in a volume range, in μl, selected from the group of ranges consisting of about 100-200, 150-250, 200-300, 250-350, 300- 400, 350-450, 400-500, 450-550, and 500-600.

11. The kit of claim 8, wherein the concentration of IGF-I is in a range selected from the group of ranges consisting of, in μg/ml, 2-5, 3-8, 4-9, 6-10, 7-30, 15- 25, 20-50, 35-45, 40-60, and 55-70.

12. The kit of claim 8, further comprising instructions for use thereof.

13. The kit of claim 8, wherein IGF is either IGF-I or IGF-II.

14. A pharmaceutical composition comprising IGF and a pharmaceutically acceptable carrier, wherein the IGF is in a concentration range, in μg/ml, selected from the group of ranges consisting of about 2-5, 3-8, 4-9, 6-10, 7-30, 15-25, 20-50, 35-45, 40-60, and 55-70.

15. The pharmaceutical composition of claim 14, wherein the IGF is in a volume range, in μl, selected from the group of ranges consisting of 100-200, 150-250, 200-300, 250-350, 300-400, 350-450, 400-500, 450-550, and 500-600.

16. The pharmaceutica composition of claim 14, wherein the IGF is IGF-I or

IGF-Π.