LH-RH interaction with the pituitary plasma membrane is affected by sex steroids

摘要: Variation of pituitary responsiveness to synthetic LH-RH was observed during different phases the menstrual cycle [l-3] . Recently changes in vitro response were reported for pituitaries male and female rats, respectively, at ages [4,5] Furthermore, stimulated release gonadotropins could be provoked by estrogen pretreatment females suffering from amenorrhoea who did not respond prior steroid application [6] Additionally, stimulated-LH strikingly higher normal pubertal children than prepubertal [7] These fmdings suggested that hypophyseal affected estradiol and/or progesterone. Additional evidence this suggestion obtained recent experiments, which showed 17 Sestradiol progesterone modulate responses adenohypophyses [8] Very recently shown bound isolated plasma membranes rat anterior [9]. LH-RH-receptor interaction with membrane characterized found a temperature pH dependent process [lo] Data currently available strongly suggest two distinct binding sites are present receptor system intact rats. But, one site no longer detected if experiments performed chronically ovariectomized rats [ 1 l] This observation data on stimulation gonadotropin