Downregulation of TGF-beta 1 gene expression in anterior pituitary cells treated with forskolin.
Transforming growth factor beta 1 (TGF-beta 1) has recently been shown to inhibit the growth of lactotropes by an autocrine/paracrine mechanism. Because the growth and function of lactotropic cells in the anterior pituitary are under control by hormones that modulate intracellular cAMP levels, the effect of a cAMP elevating agent forskolin on TGF-beta 1 and TGF-beta 1 gene expression in primary cultures of anterior pituitary cells was tested. Treatment with a dose of forskolin (5 microM), known to induce PRL gene transcription, significantly inhibited TGF-beta 1 levels in culture medium and TGF-beta 1 mRNA levels in cellular extracts. Nuclear run-off transcription analysis revealed that the forskolin effect on TGF-beta 1 mRNA expression is due to reduced transcription initiation rates. These data suggest that the transcription of TGF-beta 1 may be regulated by cAMP dependent mechanisms in anterior pituitary cells.
Pastorcic
M
M
Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman 99164-6520, USA.
Sarkar
D K
DK
D000818:Animals; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology*; D015536:Down-Regulation / Q000187:drug effects; D005260:Female; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger; D051381:Rats; D017207:Rats, Sprague-Dawley; D014158:Transcription, Genetic / Q000187:drug effects; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism
D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D005576:Colforsin