Insulin secretion, clearance and action before and after gastroplasty in severely obese subjects
Letiexhe, M.R.; Scheen, A.J.; Gérard, P.L.; Desaive, C.; Lefèbvre, P.J.
International Journal of Obesity and Related Metabolic Disorders Journal of the International Association for the Study of Obesity 18(5): 295-300
1994
ISSN/ISBN: 0307-0565 PMID: 8061722 Document Number: 427929
This study investigated the effects of a drastic weight reduction on insulin secretion rate (ISR), insulin metabolic clearance rate (MCR-I) and insulin sensitivity (S-I) in severely obese subjects. A frequently sampled intravenous glucose tolerance test (FSIVGTT, 0.3 g/kg) was performed before and 8 +- 1 months after a vertical ring gastroplasty in 12 overnight-fasted obese non-diabetic subjects; the results were compared to those obtained in 12 lean controls matched for age and sex. ISR was derived by deconvolution of plasma C-peptide levels; MCR, was obtained by dividing the area under the curve (AUC-180 min) of ISR by the corresponding AUC of plasma insulin levels (IRI); the S, and the glucose effectiveness index (S-G) were calculated by Bergman's minimal model. Before gastroplasty, obese subjects showed significantly higher ISR (P lt 0.02), lower MCR, (P lt 0.001), lower S-I (P lt 0.001) but similar S, when compared to lean controls. After gastroplasty (reduction of body weight from 104.8 +- 3.8 to 73.4 +- 3.6 kg and of BMI from 37.9 +- 0.8 to 26.5 +- 0.9 kg/m-2; p lt 0.001), ISR only decreased from 53 125 +- 7968 to 42 302 +- 3716 pmol/180 min (not significant) while AUC-IRI dramatically fell from 53 626 +- 6378 to 21 111 +- 2584 pmol.min/l; P lt 0.001); consequently, MCR, markedly increased from 526 +- 96 to 1257 +- 150 ml/min/m-2; p lt 0.01). S-I significantly rose from 3.12 +- 0.45 to 7.10 +- 1.20 times 10-4 l/mU/min (P lt 0.005) while S-G remained unchanged. Except for ISR (still higher in the obese subjects; P lt 0.05), no significant differences in MCR-I, S-I, or S-G were observed between lean controls and obese subjects after gastroplasty. In conclusion, in severely obese non-diabetic subjects, a considerable post-gastroplasty weight loss slightly reduces insulin secretion but markedly improves insulin clearance, the result being an almost complete correction of the peripheral hyperinsulinemia together with a near-normalization of the sensitivity to insulin.