Prolactin-releasing action of LRF: a central catecholamine mediated event?
Decline of plasma dopamine (DA), norepinephrine (NE), and epinephrine (EP) levels after iv administration of a 100 microgram bolus of LRF has been reported in normal men. This finding has been used to support the concept of a central dopamine mediated mechanism for LRF-induced PRL release. In the present study (including 5 postmenopausal women and 4 normal men), no detectable changes were found in plasma levels of DA, NE, EP and the DA metabolite, 3,4-dihydroxyphenylacetic acid (DOPAC) following LRF (100 microgram iv) administration. These results pertain to both groups of subjects, although the PRL increment was 2-fold greater in the postmenopausal women than in the normal men. It is concluded that peripheral administration of LRF causes no acute decline of plasma catecholamines, and that the LRF-induced release of PRL may be based on the recent demonstration in vitro of a paracrine effect, gonadotrope to lactotrope.
D015102:3,4-Dihydroxyphenylacetic Acid / Q000097:blood; D000328:Adult; D002395:Catecholamines / Q000097:blood*; D004298:Dopamine / Q000097:blood; D004837:Epinephrine / Q000097:blood; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008593:Menopause; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood; D011388:Prolactin / Q000097:blood*
D002395:Catecholamines; D015102:3,4-Dihydroxyphenylacetic Acid; D007987:Gonadotropin-Releasing Hormone; D011388:Prolactin; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine