Prolactin-induced protein kinase C activity in a mouse mammary cell line (NOG-8).
The normal mouse mammary epithelial cells, NOG-8, respond to the mitogenic signal of prolactin with a 2.5-fold increase in cell number within 3 days in vitro. When prolactin is added to subconfluent cells for 5-15 min, there is a 5-fold increase in protein kinase C activity. Upon longer exposure (24 h) to the hormone, the enzyme activity returns to that of control. The potent protein kinase C inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H7), blocks both the prolactin-induced enzyme activity and subsequent increase in cell number. Prior to prolactin treatment, 90% of the protein kinase C activity resides in the cytosol with only 10% associated with the membranes. After only 5 min of prolactin treatment, 70% of the enzyme activity is now localized to the membranes. These data suggest that prolactin uses the protein kinase C pathway for signal transduction in NOG-8 cells thus leading to enhanced cell growth.
Banerjee
R
R
Laboratory of Tumor Immunology and Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892.
Vonderhaar
B K
BK
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D004075:Diglycerides / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D004847:Epithelial Cells; D005260:Female; D007546:Isoquinolines / Q000494:pharmacology; D008321:Mammary Glands, Animal / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D010879:Piperazines / Q000494:pharmacology; D011388:Prolactin / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
D004075:Diglycerides; D007546:Isoquinolines; D008565:Membrane Proteins; D010879:Piperazines; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D011388:Prolactin; D011493:Protein Kinase C