[Role of calcium and potassium in regulating prolactin and somatotropic hormone release in cell cultures of rat adenohypophysis].

Influence of calcium, potassium and some other ions on prolactin (PRL) and growth hormone (GH) release was studied in primary monolayer cell cultures of rat adenohypophysis. In Ca2-depleted medium the rate of basal secretion of PRL (but not of GH) was decreased. Increase in calcium concentration in the medium up to 5 mM did not influence the PRL release and slightly lowered the rate of GH secretion. Potassium (30 or 55 mM) stimulated PRL and GH release. The effect of potassium was observed only in the presence of calcium. Cobalt (2 mM) strongly inhibited PRL and GH release. In the absence of bicarbonate anions basal PRL and GH secretion was decreased, but calcium-dependent effect of high potassium level (55 mM) on PRL release persisted.