Endocrine Abstracts

Introduction: Neonatal events may contribute to the development of disorders such as type 2 diabetes and obesity at adult age. We have previously shown that neonatal testosterone (T) programming of female rats is followed by insulin resistance and changes in adipose tissue distribution with centralization of body fat. Therefore, the aim of this study was to examine the effects of neonatal injection of T, estradiol (E) or dihydrotestosterone (DHT) on insulin sensitivity and size distribution of adipocytes in intra-abdominal and subcutaneous adipose tissue in female rats.

Methods: Pups received one injection of T, E, DHT or vehicle within 3 hours after birth. At 14 wks of age the rats were exposed to a euglycemic hyperinsulinemic clamp. Intra-abdominal (mesenteric) and subcutaneous (inguinal) adipose tissues were dissected and weighed. Adipocyte size was analysed using a computerized image analysis system.

Results: All groups receiving steroids were insulin resistant in comparison with controls. The mesenteric adipocyte size distribution was shifted to the right in T- and E-rats compared with controls while adipocyte size in the inguinal depot was not affected. T-rats also displayed increased mesenteric adipose tissue weight.

Analysis of all groups together showed a negative correlation between mesenteric adipocyte size and glucose infusion rate.

Conclusions: Sex hormone exposure in early life may predispose to disturbances in insulin sensitivity and adipose tissue at adult age. Directly after birth, in particular the mesenteric adipose tissue depot seems to be vulnerable to T- and E exposure which is seen as a shift to the right of the adipocyte size distribution in adulthood.