Ouabain stimulation of ⁴⁵ca⁺⁺ accumulation in the rat pituitary

Anterior pituitary tissue from rats was incubated at 37 C in Krebs’ Ringer’s bicarbonate in an atmosphere of 95% O₂ and 5% CO₂ with hourly changes of the incubation media. After a one hour preincubation, ⁴⁵Ca⁺⁺ was added to the media and its uptake by the pituitary tissue was determined. The digitalis glycoside, ouabain, in concentrations of 5 X 10^-4 and 1 × 10^-3M significantly augmented pituitary ⁴⁵Ca⁺⁺. This effect was dose and time dependent. Ouabain did not alter the washout kinetics for ¹⁴C inulin or affect pituitary weights suggesting that the observed changes in ⁴⁵Ca⁺⁺ content were the result of increased ⁴⁵Ca⁺⁺ accumulation. The effect of ouabain on calcium flux may be related to the stimulation of ACTH and GH release by ouabain.