Effects of Follicle Stimulating Hormone on Adipose Tissue Metabolic Health After Loss of Ovarian Function
Loss of ovarian function imparts increased susceptibility to obesity and metabolic disease. These effects are largely attributed to decreased estradiol (E2), but the role of increased follicle stimulating hormone (FSH) in modulating energy balance has not been fully investigated. Previous work that inhibited FSH activity in mice suggested this hormone may play a part in modulating body weight and energy expenditure after ovariectomy.  We used an alternate approach to experimentally isolate the individual and combined contributions of FSH and E2 in mediating energy imbalance and changes in tissue-level metabolic health.  Female Wistar rats were ovariectomized and given the GnRH antagonist degarelix to suppress FSH production. E2 and FSH were then added back individually and in combination for a period of 3 weeks.  Energy balance, body mass composition, and transcriptomic profiles of individual tissues were obtained.  In contrast to previous studies, ablation and replacement of FSH in our paradigm had no effect on body weight, body composition, food intake, or energy expenditure.  We did, however, observe organ-specific effects of FSH that produced unique transcriptomic signatures of FSH in retroperitoneal white adipose tissue. These included reductions in biological processes related to lipogenesis and carbohydrate transport.  Additionally, rats administered FSH had reduced liver triglyceride concentration (p<0.001), which correlated with FSH-induced changes at the transcriptomic level.  While not appearing to modulate energy balance after loss of ovarian function in rats, FSH may still impart tissue-specific effects in the liver and white adipose tissue that might affect the metabolic health of those organs. Overall design: RNA was extracted from snap-frozen retroperitoneal white adipose tissue from individual ovariectomized rats receiving either degarelix-only (n=6) or degarelix+FSH (n=5) and subjected to RNA sequencing.