Race affects insulin and GLP-1 secretion and response to a long-acting somatostatin analogue in obese adults.

OBJECTIVE

This study investigated (1) the effect of octreotide-LAR (Sandostatin-LAR Depot; Novartis) on the enteroinsular axis in a biracial cohort of severely obese adults, (2) whether octreotide suppression of insulin secretion occurs by both a direct beta-cell effect and through mediating a glucagon-like peptide 1 (GLP-1) response, and (3) whether differences in GLP-1 concentrations could explain racial differences in insulin concentrations.

DESIGN

Prospective, open-label trial using a pre-post test design.

SETTING

Single university, clinical research center.

SUBJECTS

In all, 42 healthy, severely obese Caucasian and African-American (AA) adults (93% female, 64% Caucasian, age=37.8+/-1.2 y, weight=123+/-4.2 kg, BMI=44.5+/-1 kg/m(2)), recruited through physician referral and newspaper ads, participated in the study.

INTERVENTIONS

Indices of beta-cell activity, insulin and GLP-1 response before and during a 75-gm oral glucose tolerance test were determined before and after 24 weeks of octreotide-LAR.

RESULTS

AA exhibited higher beta-cell activity, and insulin and GLP-1 concentrations than Caucasians. Octreotide-LAR suppressed the insulin and GLP-1 levels in both groups.