Endocrine Abstracts (2006) 11 P270

Hormonal profile associated with the insulin sensitive obese subjects

DH St-Pierre1, AK Karelis1, JF Henry1, FM Malita1, J Fontaine1, D Mignault1, M Brochu2, JP Bastard3, E Doucet4, K Cianflone5 & R Rabasa-Lhoret1

1Université de Montréal, Montréla, Québec, Canada; 2Université de Sherbrooke, Sherbrooke, Québec, Canada; 3Université Pierre et Marie Curie, Paris, France; 4University of Ottawa, Ottawa, Ontario, Canada; 5Université Laval, Québec, Québec, Canada.

Recently, several groups have described a subset of obese women, who despite having excessive total body fat, are insulin sensitive (ISO for Insulin Sensitive Obese), normotensive and present a favorable lipid profile. Adiponectin, ghrelin and leptin play important roles in the regulation of energy metabolism and food intake. Moreover, all three hormones have been reported to be closely linked to insulin resistance and regulated by insulin. Therefore, we propose to investigate whether ISO and “Insulin Resistant Obese” (IRO) individuals display differing adiponectin, ghrelin and leptin profiles during a hyperinsulinemic state.

Materials and methods: Eighty-nine non-diabetic obese post-menopausal women underwent a series of tests to evaluate their insulin sensitivity (euglycemic / hyperinsulinemic clamp; EHC), body composition, blood lipid profile, blood pressure and an inflammatory marker (hsCRP). Ghrelin (acylated and non-acylated), adiponectin, and leptin profile were assessed in the fasting state and during an EHC (0, 60, 160, 170 and 180 min). Subjects within the highest tertile of insulin sensitivity were described as ISO, while those within the lowest tertile of insulin sensitivity were considered as IRO.

Results: Total adiponectin profile and AUC along with maximal insulin-regulated inhibition of ghrelin, were significantly greater (P < 0.05) in ISO than in IRO. The AUC for leptin, active ghrelin and % active ghrelin along with end of EHC circulating active ghrelin were significantly decreased (P < 0.05) in ISO individuals. Adiponectin AUC (r=0.39, P < 0.05) as well as total and active ghrelin maximal inhibition during the EHC (r=−0.31, P < 0.05 and r=−0.29, P < 0.05 respectively) were significantly correlated with insulin sensitivity.

Conclusion: In a hyperinsulinemic state, total adiponectin concentrations, maximal inhibition of total ghrelin, AUC and end of EHC % active ghrelin are different between ISO and IRO subjects. These findings suggest a potential regulatory involvement of the different forms of leptin, adiponectin and the different forms of ghrelin in the ISO profile.