Stimulatory effects of prolactin and anti-prolactin receptor serum on prolactin binding sites in rat liver cells in suspension culture
Rosa, A.A.; Djiane, J.; Houdebine, L.M.; Kelly, P.A.
Biochemical and Biophysical Research Communications 106(1): 243-249
1982
ISSN/ISBN: 0006-291X PMID: 6285915 Document Number: 195035
The effects of prolactin [PRL] and a serum containing anti-PRL receptor antibodies on PRL binding sites were investigated in a suspension culture of rat liver cells. In this model, PRL binding sites decline rapidly with time, with 90% of the sites lost at 24-48 h of culture. The inclusion of 10-100 nM ovine PRL in the incubation medium, results in a 6-fold increase in prolactin binding compared to control cultures. Anti-PRL receptor serum is capable of preventing this PRL-induced increase in its receptors. However, when incubated alone, these antibodies at lower concentrations (0.5-5%) mimic the up-regulatory effect of PRL on its own binding site. In rat liver cells, as has been observed for rabbit mammary gland, the PRL molecule is not required beyond the initial binding to its receptors for its action to be attained.