The effect of gliclazide on plasma insulin, intact and 32/33 split proinsulin in South Asian subjects with Type 2 diabetes mellitus.
OBJECTIVE
Previous studies have shown that in Caucasian subjects with Type 2 diabetes mellitus (DM), the sulphonylurea glibenclamide increased insulin secretion without causing an increase in 32/33 split proinsulin secretion. South Asian subjects with Type 2 DM are thought to be more insulin resistant and the effect of sulphonylureas may be different. We therefore investigated the effect of sulphonylurea therapy with gliclazide on beta-cell function in South Asian subjects with newly diagnosed Type 2 DM.


METHODS
Glucose, insulin, and intact and 32/33 split proinsulin were measured at diagnostic oral glucose tolerance test (OGTT). After 8-12 weeks on a conventional diet, subjects with a fasting glucose > 6 mmol/l (n = 16) were commenced on gliclazide.


RESULTS
At diagnosis, those requiring gliclazide were more hyperglycaemic but there was no difference in weight or fasting insulin concentration than in the diet group. Following diet, in the gliclazide group, weight fell (P < 0.04) with no change in fasting glucose concentration. Fasting intact proinsulin, insulin and 32/33 split proinsulin remained unchanged. After gliclazide therapy weight remained unchanged, but fasting glucose fell (P < 0.003). Fasting insulin and intact proinsulin remained unchanged but 32/33 split proinsulin fell (P < 0.05). Fasting insulin to glucose ratio significantly improved after gliclazide (P < 0.006).


CONCLUSIONS
In South Asian subjects treated with gliclazide the reduction in fasting glucose concentrations appears to be due to an improvement in insulin sensitivity as well as in beta-cell function.
Ammari
F
F
Diabetes Care, Leicester General Hospital, UK.
Davies
M J
MJ
Koppiker
N
N
Gregory
R
R
Burden
A C
AC
D000328:Adult; D000368:Aged; D001210:Asia, Southeastern / Q000208:ethnology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D005260:Female; D005907:Gliclazide / Q000627:therapeutic use*; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011384:Proinsulin / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism; D006113:United Kingdom
D007004:Hypoglycemic Agents; D007328:Insulin; D011498:Protein Precursors; C070703:proinsulin, des(31,32)-; D011384:Proinsulin; D005907:Gliclazide