Lower total fasting plasma adiponectin concentrations are associated with higher metabolic rates.

CONTEXT

The possible role of adiponectin, a protein uniquely produced by the adipose tissue and significantly reduced in obesity and other insulin-resistant states, in the regulation of energy expenditure (EE) is still poorly understood.

OBJECTIVE

The objective of the study was to investigate the relationship between total fasting plasma adiponectin concentrations and the various components of EE measured in a metabolic chamber in Pima Indians and to test whether body fat distribution may have a role in this association.

DESIGN

This was a cross-sectional study.

SETTING

The study was an inpatient clinical research unit.

PARTICIPANTS

Sixty nondiabetic Pima Indians (45 males and 15 females), aged 18-45 yr, spanning a wide range of adiposity (body mass index 19.6-46.2 kg/m(2)) participated in the study.

MAIN OUTCOME MEASURES

Total fasting plasma adiponectin concentrations, EE (24-h respiratory chamber), insulin sensitivity (euglycemic-hyperisulinemic clamp), body composition (dual-energy x-ray absorptiometry), and body fat distribution (waist to thigh ratio) were the main outcome measures.

RESULTS

Total fasting plasma adiponectin concentrations are negatively associated with sleep EE adjusted for sex, age, fat-free mass, and fat mass. This correlation is still significant, although attenuated, after inclusion of insulin-stimulated glucose disposal among the regressors and further attenuated when adjusted also for waist to thigh ratio.

CONCLUSIONS

The decrease in total fasting plasma adiponectin concentrations that accompanies fat accumulation may be a mechanism to prevent further weight gain by decreasing insulin sensitivity and increasing energy expenditure.