Cadmium exposure inhibits the prolactin secretory response to thyrotrophin releasing hormone (TRH) in vitro.
In vitro dose response (0.1-100 microM) and time course studies were performed on anterior pituitary cells isolated from female Sprague-Dawley rats in the diestrous stage of the estrous cycle. All doses of TRH produced a significant increase in prolactin release by 5 min which was sustained for 30 min. Pretreatment with 25 or 50 microM Cd for 2 or 4 h produced a significant decrease in prolactin secretion during Cd exposure and in the prolactin secretory response to 1 microM TRH. These results suggest that Cd pretreatment alters the subsequent ability of the lactotrophs to respond to the physiological secretagogue TRH. This alteration does not appear to be due to a rebound phenomenon since basal prolactin release was the same in Cd-pretreated and control cells once the metal was removed. These results suggest that Cd pretreatment produces a significant decrease in prolactin release from the anterior pituitary lactotrophs in response to subsequent TRH stimulation in vitro.
Winstel
C
C
Department of Zoology, Miami University, Oxford, OH 45056.
Callahan
P
P
D000818:Animals; D002104:Cadmium / Q000633:toxicity*; D002478:Cells, Cultured; D005260:Female; D007700:Kinetics; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical; D013973:Thyrotropin-Releasing Hormone / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D013997:Time Factors
D002104:Cadmium; D013973:Thyrotropin-Releasing Hormone; D011388:Prolactin