Estradiol potentiation of gonadotropin-releasing hormone responsiveness in the anterior pituitary is mediated by an increase in gonadotropin-releasing hormone receptors

摘要: In order to investigate the mechanism by which 17 beta-estradiol potentiates action of gonadotropin-releasing hormone on anterior pituitary in vitro, cultured cells from immature female rats were used as model system. Cultures exposed estradiol at concentrations ranging 10(-10) 10(-6) mol/L exhibited a significant augmentation luteinizing release response 4-hour (10 mumol/L) challenge dose 10(-9) compared that control cultures. The was also dependent duration exposure. When these cultures incubated with tritium-labeled L-leucine, an increase incorporation radiolabeled amino acid into total proteins greater than controls observed. A parallel stimulatory effect iodine 125-labeled D-Ala6 binding different and various lengths time showed capacity this abrogated cycloheximide. Analysis data activity due change number sites rather affinity. These results suggest (1) treatment increases receptors for hormone, (2) augmentary level might be mediated, least part, (3) new protein synthesis may involved estradiol-mediated receptor induction.