Impaired insulin clearance, initial regulator of obesity-associated hyperinsulinemia, study finds

China: Hyperinsulinemia in obese patients may be due to decreased insulin clearance rather than increased insulin secretion, reveals a recent study in the journal Diabetes Care. Further, it was found that changes in circulating conjugated bile acids (BAs) may be an important player in regulating insulin clearance. 

In the study, Hongwen Zhou, Department of Endocrinology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China, and colleagues aimed to examine the roles of insulin clearance and insulin secretion in the development of hyperinsulinemia in obese patients and to reveal the association between insulin clearance and bile acids.

In cohort 1, the researchers evaluated insulin secretion, sensitivity, and endogenous insulin clearance using a glucose tolerance test in 460 recruited participants. In cohort 2, they assessed insulin secretion, endogenous and exogenous insulin clearance, and insulin sensitivity in 2, 81 participants who underwent an intravenous glucose tolerance test and a hyperinsulinemic-euglycemic clamp. Obese participants without diabetes were further divided into 10 quantiles in cohort 1 and into tertiles in cohort 2 based on insulin resistance levels ranging from mild to severe. In order to examine the association between BAs and insulin clearance, forty serum BAs were measured in cohort 2.