Plasma concentrations of glucagon during hyperglycemic clamp with or without somatostatin infusion in obese subjects.
The aim of the present study was to evaluate whether the inhibitory effect on pancreatic A-cell exerted by hyperglycemic hyperinsulinemia and/or by somatostatin administration is impaired in human obesity. For this purpose plasma glucagon concentrations were measured in 8 obese and 8 nonobese nondiabetic subjects during a 4-h hyperglycemic clamp. Synthetic cyclic somatostatin-14 was infused at the rate of 2.5 nmol/min during the third hour of the study. Fasting plasma glucagon was higher in obese than in nonobese subjects (242 +/- 32 vs 163 +/- 15 pg/ml, p less than 0.05) (mean +/- SEM). In the last 20 min of the glucose infusion period preceding somatostatin administration (100-120 min of the study) plasma glucagon averaged 195 +/- 26 pg/ml in obese and 122 +/- 13 pg/ml in nonobese subjects (p less than 0.05), with a reduction of 19 +/- 3% in the former and 28 +/- 4% in the latter (p = n.s.). In both groups somatostatin infusion did not result in a further decrease in plasma glucagon, which averaged 192 +/- 27 pg/ml in obese and 123 +/- 16 pg/ml in nonobese subjects (p less than 0.05) in the 160-180 min period of the study. Also after discontinuing somatostatin infusion plasma glucagon levels did not change. These results suggest that in human obesity hyperglycemic hyperinsulinemia has a normal inhibitory effect on pancreatic A-cell and that somatostatin administration has no additive effect on hyperglycemia and hyperinsulinemia in either obese or nonobese nondiabetic subjects.
Bonora
E
E
Cattedra di Malattie del Metabolismo, Università di Verona, Italy.
Moghetti
P
P
Cacciatori
V
V
Zenere
M
M
Tosi
F
F
Travia
D
D
Zoppini
G
G
Perobelli
L
L
Muggeo
M
M
D000328:Adult; D000704:Analysis of Variance; D005260:Female; D005934:Glucagon / Q000097:blood*; D006801:Humans; D006943:Hyperglycemia / Q000097:blood*; D008297:Male; D009765:Obesity / Q000097:blood*; D013004:Somatostatin / Q000494:pharmacology*; D013223:Statistics as Topic
D013004:Somatostatin; D005934:Glucagon