JPH085799B2 - Antidiabetic - Google Patents

Description

TECHNICAL FIELD The present invention relates to a preventive agent for diabetes.

[Prior Art and Its Deficiencies] WHO classifies diabetes into two types, type I diabetes and type II diabetes, based on clinical symptoms and epidemiological study results. The currently conjectured cause of type I diabetes is the genetic background (HLA: Hu:
Man Leukocyte Antigen) is based on abnormal autoimmune disease. As a result, a new direction has emerged in terms of therapy, by suppressing this immune reaction, it is possible to prevent its onset. For example, various immunosuppressive therapies for type I diabetes such as insulin-dependent diabetes mellitus and lean diabetes have already been reported, but the effects are still unsatisfactory.

[Problems to be Solved by the Invention] The present invention has a superior effect to conventional drugs used for immunosuppressive therapy for type I diabetes, especially diabetes I
The purpose is to provide a preventive drug for type 2 diabetes.

[Means for Solving Problems] That is, the present invention provides a diabetes preventive agent containing cholera toxins as an active ingredient.

[Effect of the Invention] According to the present invention, a diabetes preventive agent having an excellent preventive effect can be obtained.

[Detailed Description of the Invention] Cholera toxin, which is a typical example of the active ingredient of the antidiabetic agent of the present invention, has a molecular weight of about 84,000 consisting of one subunit A having a molecular weight of about 27,000 and five subunit B having a molecular weight of about 11600.
The amino acid sequences of these subunits have been deduced based on the sequence of the cloned DNA (JJ Mekalanos et al., Nature (306).
p.551-557 (1983)). This substance is produced by the gram-negative bacterium Vibrio cholerae, but the cholera toxin used in the present invention is not necessarily limited to that produced by this bacterium, and for example, by genetic engineering means according to a conventional method. It may be produced by other microorganisms or cultured cells. Generally, in a protein having physiological activity, the structure showing the physiological activity is not specified in a general manner,
It is widely recognized by those of skill in the art that a range of structural differences are acceptable to exhibit substantially the same bioactivity. Therefore, the cholera toxins as the active ingredient of the antidiabetic agent of the present invention include, in addition to the above-mentioned cholera toxin,
A protein in which the structure of Escherichia coli enterotoxin or the cholera toxin is partially modified, for example, a protein in which some amino acids are replaced with other amino acids, some amino acids are removed, or some amino acids are added. In addition, those having a diabetes preventive effect equivalent to that of the toxin are also included.

The antidiabetic agent of the present invention has a preventive effect on type I diabetes caused by abnormal autoimmune diseases.

The route of administration is preferably a parenteral route, for example, intravenous injection, intraperitoneal injection, intramuscular injection, subcutaneous injection and the like. The single dose varies depending on the degree of diabetes mellitus, the condition of the patient, etc. and is appropriately determined by the judgment of the doctor for each clinical case, but is usually 0.5 μg / kg to 50 μg / kg. Similarly, the number of administrations and the administration period are appropriately determined by the judgment of the doctor.

The toxicity of cholera toxin to mammals is, for example, LD ₅₀ of 5 μg / mouse in mice.

The antidiabetic agent of the present invention may be a cholera toxin preparation itself, or an excipient commonly used in parenteral medicine, such as a diluent, buffer, osmotic pressure adjusting agent, stabilizer, It may be a mixture with a preservative or the like. For example, 0.1 to 2.0 mg of cholera toxin in physiological saline or phosphate buffer.
The mixture mixed at a concentration of / ml is used as an injection.

Next, the effects of the diabetes preventive agent of the present invention will be specifically described with reference to Examples.

[Example] In this example, NOD mice were used. NOD mouse is ICR
It is a spontaneous type I diabetic mouse isolated from a mouse. Insulinitis appears from the age of 30 days after birth, and β-cell collapse occurs in females from the age of 90 days, resulting in overt diabetes. And, due to the absolute lack of insulin, it will die in about one month. From a number of experimental results in NOD mice and BB rats, which are typical models of IDDM (insulin-dependent diabetes mellitus), genetic (thymus → T cells) → isletitis → islet β cell destruction → overt diabetes mellitus Is understood.

(1) Cholera toxin and its administration method The cholera toxin used in the experiment was separated and purified from cholera.

The administration method was as follows: 0.2 ml of a phosphate buffer containing 1 μg of cholera toxin was injected into the NOD mouse of 60-day-old, a test mouse, by tail vein injection.

(2) Reagent for measuring blood glucose level and method thereof As a glucose measuring reagent used in the experiment, a Glucose C-Test kit manufactured by Wako Pure Chemical Industries, Ltd. was used.

As a measuring method, blood samples were collected from test mice, and the serum obtained by centrifugation was used as a sample. After mixing and heating with a coloring reagent, the absorbance was measured with a spectrophotometer to determine the glucose content.

(3) Results The results are shown in the figure. In the figure, white circles show the results for the control (n = 8), and black circles show the results for the administration of cholera toxin (n = 7). As is clear from the figure, untreated NOD mice began to have an elevated blood glucose from around the age of 130, and showed an average blood glucose level of 350 mg / dl at the age of 160 days, whereas cholera toxin-treated NOD mice showed No increase in blood sugar was observed up to the age of 160 days, indicating that the antidiabetic agent of the present invention has an excellent effect of preventing the development of insulin-dependent diabetes.

[Brief description of drawings]

The figure is a graph showing the blood glucose levels of NOD mice to which the antidiabetic agent of the present invention was administered and NOD mice to which it was not administered over time.

Claims (1)

[Claims] 1. A diabetes preventive agent comprising cholera toxins as an active ingredient.