Insulin secretion in Down's syndrome.

Insulin secretion after oral (100 g) and i.v. glucose (0.33 g/kg b.w.) was studied in 14 patients with 21-trisomy (Down's syndrome) and in 18 normal subjects. Plasma immunoreactive insulin (IRI), fasting and at predetermined time intervals during each glucose load, was measured by a double antibody method (Hales-Randle). Tolerance to oral glucose in Down's patients was found to be normal though a flat, late peaked glycaemic response was characteristic of the group. Fasting IRI and insulin levels after oral glucose in patients did not significantly differ from those in the normal group. After i.v. glucose, the patients showed a slower decline of the blood sugar, maintaining significantly higher levels than the normals at 30, 40, 50 and 60 min after the glucose load. However, the peripheral glucose uptake expressed by the K index (Conard) did not significantly differ from the normal despite the lower K values in the patients. Insulin release after i.v. glucose showed some differences between both groups. - The present study cannot support a causal relationship between D.M. and the 21-trisomy through an altered insulin secretion. [ABSTRACT FROM AUTHOR]