Effects of Short Term Administration of Genistein on Hypothalamic and Anterior Pituitary Hormones in Ovariectomized Gilts

Abstract

Administration of genistein to barrows increased anterior pituitary (AP) concentrations of IGF-I and LH and increased expression of AP IGF receptor. Whether similar changes occur in gilts remains to be determined. The objective of this experiment was to determine if short term administration of genistein increased expression of components of the AP IGF system and hypothalamic hormones and receptors involved in gonadotropin synthesis and/or release in the gilt. Sixteen crossbred gilts of similar weight (97.7 kg) were ovariectomized and assigned to either control (C; n = 8) or genistein (G; n = 8) groups. Genistein pigs received 800 mg of genistein in DMSO while C pigs received an equal volume of DMSO i.m. on day 0, 1, 2, and 3. Blood samples were obtained on day 0, 1, 2, and 3. Pigs were slaughtered on d 4 when blood, AP, and medial basal hypothalami (MBH) were collected. No difference was detected (P > 0.05) in AP concentrations of IGF-I or serum concentrations of IGF-I in C and G pigs. Anterior pituitary concentrations of LH were greater (P 0.05) in C and G pigs. Relative expression of AP IGFBP-5 and GnRHR was increased (P < 0.05) in G pigs compared with C pigs. Relative expression of AP LHβ did not differ between C and G pigs. Relative expression of MBH kisspeptin was greater (P < 0.01) in G pigs than C pigs. These data provided evidence that short term administration of genistein increased expression of hypothalamic and hypophyseal hormones in gilts which could influence subsequent reproduction.