Prolactin secretion in anterior pituitary cells: effect of eicosanoids.
Ovariectomized Fischer 344 rats were implanted with silastic capsules containing estradiol for approximately 4 weeks to increase the number of lactotrophs in the anterior pituitary gland. Anterior pituitary cells were enzymatically dispersed and cultured for 1 day and challenged with eicosanoids or other prolactin (PRL) secretagogues. The isolated pituitary cells from estradiol-pretreated animals exhibited an increase in the ability to secrete PRL in the presence of maximally effective concentrations of thyrotropin releasing hormone (TRH), arachidonic acid or 5,6-epoxyeicosatrienoic acid (5,6-EET). Anterior pituitary cells from estradiol-pretreated animals also showed an increased activity of cytochrome P-450. The possible involvement of cytochrome P-450 in PRL secretion from anterior pituitary animal cells isolated from animals pretreated with estradiol was shown by the fact that these anterior pituitary cells increased the synthesis of 5,6-EET, a potent PRL releasing agent. TRH and 5,6-EET increased the mobilization of both cyclic AMP and cytoplasmic calcium to about the same extent. The data suggest that cytochrome P-450 is important in the release of PRL from anterior pituitary cells isolated from estradiol-pretreated Fischer 344 rats and that a product of cytochrome P-450-catalyzed epoxidation of arachidonic acid, 5,6-EET, plays a significant role in the release of PRL.
Cashman
J R
JR
Department Pharmaceutical Chemistry School of Pharmacy, University of California San Francisco 94143-0446.
Snowdowne
K W
KW
D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007700:Kinetics; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344; D013739:Testosterone / Q000378:metabolism
D065607:Cytochrome P-450 Enzyme Inhibitors; D013739:Testosterone; D004958:Estradiol; C040776:5,6-epoxy-8,11,14-eicosatrienoic acid; D011388:Prolactin; D003577:Cytochrome P-450 Enzyme System; D000242:Cyclic AMP; D015126:8,11,14-Eicosatrienoic Acid; D002118:Calcium