Phorbol ester stimulates prolactin release but reduces prolactin mRNA in the human B-lymphoblastoid cell line IM-9-P3

• Published in: Molecular and cellular endocrinology Vol. 66; no. 2; p. 153
• Main Authors: Gellersen, B, DiMattia, G E, Friesen, H G, Bohnet, H G
• Format: Journal Article
• Language: English
• Published: Ireland 01-10-1989
• Subjects: 1-Methyl-3-isobutylxanthine - pharmacology; B-Lymphocytes - metabolism; Blotting, Northern; Bucladesine - pharmacology; Cell Line; Cyclic AMP - physiology; Dose-Response Relationship, Drug; Humans; Prolactin - metabolism; Protein Kinase C - antagonists & inhibitors; RNA, Messenger - drug effects; RNA, Messenger - metabolism; Tetradecanoylphorbol Acetate - pharmacology
• ISSN: 0303-7207
• DOI: 10.1016/0303-7207(89)90027-0

The phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) stimulated prolactin (PRL) release from the PRL producing human B-lymphoblastoid cell line IM-9-P3 within 30 min with an EC50 of 5 x 10(-9) M. Increased release was entirely attributable to a loss from intracellular PRL pools. No change in hPRL mRNA was observed during 8 h of exposure to TPA. Prolonged exposure of the cells to 2 x 10(-7) M TPA, however, led to a maximal reduction of hPRL mRNA levels after 24 h and a subsequent recovery by 72 h. Secretory rates followed a corresponding kinetic. The relative abundance of c-myc mRNA was not affected, although a persistent inhibition of cellular proliferation occurred upon chronic exposure to TPA. The addition of dibutyryl cAMP caused a minor transient increase in hPRL secretion by 35% after 1 h.