THE EFFECTS OF OOPHORECTOMY AND FEMALE SEX STEROIDS ON GLUCOSE KINETICS IN THE RAT

In order to clarify the roles played by female sex steroids on glucose metabolism, basal glucose kinetics were studied in control sham opera ted (C), oophorectomised (O), 17-beta-oestradiol treated oophorectomis ed (1.5 mu g/day) (E) and progesterone treated oophorectomised (1.5 mg /day) (P) female rats. Hormone (or vehicle only) delivery was via osmo tic pumps which were inserted at the time of oophorectomy (or sham ope ration) 7 days prior to metabolic testing. In fasted anaesthetised rat s, hepatic glucose production (HGP), plasma glucose metabolic clearanc e rate (MCR) and glucose uptake indices (GUI) of selected peripheral t issues were measured using radioactive tracer methodology. Following s urgery, the O rats significantly gained and the E rats significantly l ost weight compared to the C rats. Plasma insulin and glucose were not different between groups. HGP and MCR were increased by 24-29% (P < 0 .005) and 19-28% (P < 0.001), respectively, in the O compared to the C , E and P rats. The GUI of brown adipose tissue was significantly redu ced in the P compared to the C rats (3 +/- 1 vs 25 +/- 10 mu mol/100 g /min). In conclusion, female sex steroid hormones significantly influe nce rat body weight, hepatic glucose metabolism and the metabolism of brown adipose tissue.