Glucose and insulin responses to intravenous glucose challenge in relatives of Nigerian patients with non-insulin-dependent diabetes mellitus.
We analysed blood insulin and glucose concentrations before and during frequently sampled intravenous glucose tolerance tests (FSIGT) in 2 groups of Nigerian subjects: (A) Control group (n = 18), without a positive family history of diabetes mellitus, and (B) Experimental group (n = 16), comprising age-, sex- and body mass-matched first-degree relatives of patients with non-insulin-dependent diabetes mellitus (NIDDM). In comparison with Group A subjects, those in Group B had: (i) higher fasting plasma glucose level (mean +/- S.E.M. 4.1 +/- 0.1 vs. 3.8 +/- 0.11 mmol/l, P < 0.05); (ii) similar fasting serum insulin levels (6.7 +/- 5.0 vs. 5.8 +/- 5.6 mU/l, P = NS); (iii) lower mean incremental area under the first-phase (t = 0-10 min) post-glucose challenge insulin curve (376.9 +/- 8.8 vs. 435.6 +/- 5.6 mU/min l-1, P < 0.05); (iv) increased incremental area under the second-phase (t = 10-182 min) post-glucose challenge insulin curve (432.9 +/- 11.5 vs. 161.3 +/- 8.7 mU/min l-1, P < 0.05); (v) reduced KG rate constant of glucose elimination (0.97 +/- 0.12 vs. 1.41 +/- 0.12%/min, P < 0.05). These results suggest that the subjects with a positive family history of NIDDM have a reduced beta-cell insulin secretory reserve (from reduced first-phase insulin response), tendency to rebound hyperinsulinemia during the latter phase of the insulin secretory response, a degree of tissue insulin insensitivity (as evident from high fasting plasma glucose despite similar insulin levels) and a diminished glucose disposal rate, in comparison with subjects without a family history of NIDDM. These features predict subsequent development of diabetes and suggest that as in Caucasians, first-degree relatives of Nigerian patients with NIDDM are at greater risk for future development of the disease.
Ezenwaka
C E
CE
Department of Chemical Pathology, University College Hospital, Ibadan, Nigeria.
Akanji
A O
AO
Osei
K
K
Adejuwon
C A
CA
O'Dorisio
T M
TM
Cottrell
D A
DA
Akinlade
K S
KS
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology / Q000235:genetics*; D005190:Family; D005260:Female; D005951:Glucose Tolerance Test; D006801:Humans; D007328:Insulin / Q000097:blood*; D008297:Male; D009549:Nigeria; D012016:Reference Values; D012307:Risk Factors
D001786:Blood Glucose; D007328:Insulin