Transforming growth factor-beta and activin inhibit basal secretion of prolactin in a pituitary monolayer culture system.
Incubations of rat anterior pituitary cells with transforming growth factor (TGF)-beta 1 for 48 hr suppressed the secretion of basal prolactin (PRL) in a dose-dependent manner (ED50, 100 pg/ml). Activin, a gonadal hormone processing cysteine distribution similar to TGF beta, also suppressed basal PRL secretion, but it was less effective (ED50, 4 mg/ml). Treatment with TGF beta 1 significantly suppressed basal PRL secretion from the pituitary after 24 hr and up to 72 hr of incubation. TGF beta 1 also inhibited thyrotropin-releasing hormone-mediated PRL secretion and activin inhibited thyrotropin-releasing hormone-mediated PRL secretion slightly, but significantly. In addition, we also measured the secretion of growth hormone by cultured pituitary cells treated with TGF beta 1 or activin for 24 to 72 hr. TGF beta 1 and activin showed an opposite effect on growth hormone secretion; TGF beta stimulated and activin inhibited basal secretion of growth hormone. These results suggest that TGF beta 1 is a potent inhibitor of basal secretion of PRL by the pituitary, and both TGF beta 1 and activin play a multifunctional role in basal secretion of pituitary hormones.
Murata
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Department of Anatomy and Cell Biology, University of Southern California School of Medicine, Los Angeles 90033.
Ying
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SY
D028341:Activins; D000818:Animals; D002478:Cells, Cultured; D004261:DNA Replication / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism; D013006:Growth Hormone / Q000378:metabolism; D066298:In Vitro Techniques; D007265:Inhibins / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000187:drug effects* / Q000378:metabolism; D011388:Prolactin / Q000187:drug effects*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D011994:Recombinant Proteins / Q000494:pharmacology; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D028341:Activins; D007265:Inhibins; D011388:Prolactin; D005640:Follicle Stimulating Hormone; D013006:Growth Hormone