Modulating actions of estradiol on gonadotropin-releasing hormone-stimulated prolactin secretion in postmenopausal individuals.
The temporal aspects of estrogen treatment on serum prolactin concentrations basally and in response to a 10 micrograms intravenous injection of gonadotropin-releasing hormone were assessed in eight postmenopausal women. The response of prolactin to gonadotropin-releasing hormone stimulation was compared with that of follicle-stimulating hormone and luteinizing hormone obtained simultaneously. Basal serum prolactin increased significantly (p less than 0.001) in response to estrogen treatment, and a positive correlation was found between the serum concentrations of estradiol and prolactin (r2 = 0.266; p = 0.0011). Gonadotropin-releasing hormone induced a significant increase in serum prolactin concentrations, which was greater after 5 to 10 days of estrogen treatment compared with that in the estrogen-depleted state (p = 0.031). No correlation was found between gonadotropin-releasing hormone-stimulated prolactin and luteinizing hormone or follicle-stimulating hormone release. These data demonstrate that estrogen treatment of previously hypoestrogenemic postmenopausal women potentiates gonadotropin-releasing hormone-stimulated prolactin release. Furthermore, our data suggest that the previously described paracrine interaction between the gonadotropins and lactotropes exerted by gonadotropin-releasing hormone does not appear to be mediated via increased gonadotropin release.
D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D006801:Humans; D007986:Luteinizing Hormone / Q000378:metabolism; D008593:Menopause / Q000187:drug effects / Q000502:physiology*; D008875:Middle Aged; D010906:Pituitary Hormone-Releasing Hormones / Q000494:pharmacology*; D011388:Prolactin / Q000378:metabolism*; D013268:Stimulation, Chemical; D013997:Time Factors
D010906:Pituitary Hormone-Releasing Hormones; D004958:Estradiol; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone