The effect of oestrogen pretreatment on subsequent response to luteinizing hormone releasing hormone in normal women.
Twenty-two normal, regularly menstruating female subjects had an LHRH test performed before and after pretreatment with 0.5 mg, 1 mg. or 2.5 mg of oestradiol benzoate during the follicular phase of their menstrual cyclees (days 4-8). Two further women acted as controls and received no oestrogen; they showed identical responses for both LH and FSH release when LHRH tests were performed at intervals of 48 h. Oestrogen pretreatment induced a biphasic effect upon subsequent LHRH response. Four subjects retested 20 h after 0.5 mg oestradiol benzoate showed either no change or a slight suppression of LH and FSH release. Fifteen of the eighteen women pretreated with oestradiol benzoate and retested 44 h later showed significantly increased LH release and fourteen significantly increased FSH release when compared to their control responses. The responses appeared to be dose related with a positive correlation between sum of LH increments and basal oestradiol levels (R = 0.61; P less than 0.001) and a similar correlation (r = 0.67; P less than 0.001) between sum of FSH increments and basal oestradiol levels. The physiological significance of this biphasic action of oestrogen upon pituitary sensitivity is discussed in relation to the control of the menstrual cycle.
D000328:Adult; D001565:Benzoates; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000097:blood / Q000494:pharmacology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood*; D008598:Menstruation; D011863:Radioimmunoassay
D001565:Benzoates; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone