Epidermal growth factor stimulates the prolactin synthesis and secretion in rat pituitary cells in culture (GH4C1 cells) by increasing the intracellular concentration of free calcium.

Epidermal growth factor (EGF) stimulated the prolactin (PRL) synthesis and release from the GH 4 C 1 cells in a dose-dependent manner. The ED 50 was between 10 -11 and 10 -10 mol/l. The minimal effect was obtained at 10 -9 mol/l EGF for the release, and 10 -8 mol/l EGF for the synthesis. EGF stimulated the release of PRL from cell perfusion columns after a lag period of about 30 s. The minimal secretion of PRL occurred about 60 s after the start of stimulation. The PRL secretion declined to basal levels within 2 min