Mitogenic effect of a factor from rat somatomammotrophs on mammary epithelial cells

Piotr Chomczynski, Tomasz Kuryl, Anoop Brar

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We have previously established a somatomammotroph cell line (rPCO) derived from normal rat pituitary that secretes GH and PRL. In this study we report that conditioned medium from rPCO cells (CM-rPCO) exhibited a stimulatory effect on the growth of rat mammary epithelial cells in culture. Fractionation of CM-rPCO revealed that the growth-promoting activity of CM-rPCO was associated with a fraction eluting from a diethylaminoethyl-Sephacel column at 0.5 M NaCl. The growth-promoting activity of this fraction was abolished by trypsin and was resistant to dithiothreitol treatment. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the predominant components of the 0.5-M NaCl fraction were proteins migrating at the 14-18K region of the gel. The 0.5-M NaCl fraction did not contain immunodetectable GH or PRL. Further fractionation of CM-rPCO on a heparin-agarose column showed that the growth-promoting activity eluted at 0.9 M NaCl. The two predominant proteins in this fraction had apparent mol wt of 14.5K and 18.2K. Based on the structural and biological properties, several known hormones and growth factors were excluded from consideration as potential candidates responsible for the growth-promoting effect of the 14-18K proteins. It is postulated that this group of 14-18K proteins contains a new factor(s) that affects the growth of mammary epithelial cells.

Original languageEnglish
Pages (from-to)228-234
Number of pages7
Issue number1
StatePublished - Jul 1992


Dive into the research topics of 'Mitogenic effect of a factor from rat somatomammotrophs on mammary epithelial cells'. Together they form a unique fingerprint.

Cite this