The effects of oophorectomy and female sex steroids on glucose kinetics in the rat

Abstract

In order to clarify the roles played by female sex steroids on glucose metabolism, basal glucose kinetics were studied in control sham operated (C), oophorectomised (O), 17-β-oestradiol treated oophorectomised (1.5 μg/day) (E) and progesterone treated oophorectomised (1.5 mg/day) (P) female rats. Hormone (or vehicle only) delivery was via osmotic pumps which were inserted at the time of oophorectomy (or sham operation) 7 days prior to metabolic testing. In fasted anaesthetised rats, hepatic glucose production (HGP), plasma glucose metabolic clearance rate (MCR) and glucose uptake indices (GUI) of selected peripheral tissues were measured using radioactive tracer methodology. Following surgery, the O rats significantly gained and the E rats significantly lost 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 reduced in the P compared to the C rats (3 ± 1 vs 25 ± 10 μmol/100 g/min). In conclusion, female sex steroid hormones significantly influence rat body weight, hepatic glucose metabolism and the metabolism of brown adipose tissue.