The effect of the pituitary hormone prolactin on in vitro proliferation of human keratinocytes has been studied. Cell proliferation was determined by [3H] thymidine incorporation and cell enumeration in culture. Physiologic concentrations of prolactin markedly stimulated proliferation of newborn foreskin keratinocytes in serum-free medium. In addition, it was able to replace almost completely the growth-promoting effects of bovine pituitary extract, a commonly added supplement for keratinocyte culture. This activity was also evident in the absence of epidermal growth factor, but required the presence of insulin. Radioligand binding studies confirmed the expression of specific prolactin binding sites (Kd 8.9 nM; 1350 sites per cell) on freshly procured keratinocyte membranes. These results extend its hormonal influences to include regulation of in vitro proliferation of human keratinocytes, and suggest the possibility of a completely defined growth medium for keratinocytes.
- epidermis/pituitary hormones/serum-free culture/receptors
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology