[The effect of a short-term reducing diet on the effect of insulin in type 2 diabetes mellitus].

BACKGROUND

Insulin resistance is in addition to impaired beta-cell function decisive for the development of type 2 diabetes. It is also known that obesity creates conditions for the development of insulin resistance. The authors tried therefore to influence insulin sensitivity by short-term reducing diets in obese type 2 diabetics.

METHODS AND RESULTS

The group of patients comprised 12 obese type 2 diabetics, BMI: 40.3 +/- 8.9 kg/m2, age 50 +/- 8 years. The control group was formed by 12 healthy non-obese subjects. The following parameters of glucose tolerance were assessed: total glucose consumption to maintain euglycaemia (M) during an isoglycaemic hyperinsulinaemic clamp on a Biostator, index of tissue sensitivity to insulin (M/I), metabolic glucose clearance (MCRG), number of insulin receptors on erythrocytes (Ro) and the insulin affinity for receptors (Ko). A reducing diet, 600 kcal/day, was served for 7 days during hospitalization. The body weight of diabetics dropped by 3.2 +/- 1.5 kg, p < 0.001, there was a significant decline of the basal blood sugar level (G(o)) from 11.4 +/- 3.6 to 8.4 +/- 3.0 mmol/l, p < 0.01; 2 there was a significant reduction of the serum insulin level (Io) from 30 +/- 18 to 27 +/- 19 mU/l, p < 0.02, whereby glucose uptake M increased from 24.0 +/- 7.5 to 29.5 +/- 8.9 mumol/kg/min, p < 0.01 and at the same time the metabolic glucose clearance increased from 2.3 +/- 0.9 to 4.0 +/- 2.5 ml/kg/min, p < 0.01, while the index of tissue sensitivity to insulin M/I increased less significantly from 16.3 +/- 7.4 to 18.0 +/- 10.5 mumol/kg/min per mU x 100). There was a decline in the number of insulin receptors on erythrocytes from 245 +/- 66 to 192 +/- 61 pmol/l, p < 0.02, whereby their affinity improved: 12.8 +/- 3.9 as compared with 17.3 +/- 5.4 10(8) l/mol, p < 0.01 but the insulin bond remained unchanged.

CONCLUSIONS

A short-term reducing diet leads to improvement of the majority of investigated indicators which is manifested in particular by improved action of insulin, above all at a postreceptor level. Significant reduction of the number of insulin receptors was partly compensated by improved affinity, while the insulin bond did not change in a marked way.