The effect of gonadotropin releasing hormone (GnRH) antagonism on feeding behavior in female rats

Abstract

Estrogen replacement in ovariectomized rats reduces food intake specifically during the light phase, suggesting that estrogen exerts an anorectic action by modifying circadian feeding rhythm. Ovariectomy is known to elevate levels of gonadotropin releasing hormone (GnRH) and luteinizing hormone (LH) via the negative feedback system of the hypothalamic‐pituitary‐gonadal (HPG) axis. However, the contribution of GnRH and/or LH to the hypophagia induced by ovariectomy remains unknown. To elucidate the role of GnRH and/or LH in the feeding regulation, we examined the effect of GnRH antagonism on feeding behavior in female rats. Female Wistar rats were injected subcutaneously with either 1mg/kg degarelix, a GnRH antagonist, (De group) or 5% mannitol (Veh group), and were provided free access to water and a standard rodent chow. We found that daily food intake and body weight gain were significantly greater in the De group than the Veh group. Food intake during the light phase was not different between the groups, while food intake during the dark phase was greater in the De group than the Veh group. These results suggest that estrogen regulates daily energy intake, and GnRH and/or LH possibly modulate diurnal pattern of feeding behavior.Support or Funding InformationJPSP KAKENHI #15K12355 and 24500975 to Akira TakamataThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.