Hormonal relase by dispersed pituitary cells.

Abstract

Dispersed anterior pituitary cells were prepared by treatment of hog pituitaries with collagenase. The cell yield based on DNA recovered in intact cells after collagenase treatment was 5–10%. Ninety percent of the cells appeared intact by phase contrast microscopy. The three major cell types were identifiable by Mallory-Heidenhain staining. The dispersed cells incorporated glucose carbon into CO2 and leucine into protein more rapidly than corresponding slices. Increasing the glucose concentration of the medium caused a progressive rise in cellular growth hormone (GH) content and in leucine incorporation into protein. The dispersed cells were capable of releasing immunoreactive GH and bioassayable thyroid-stimulating hormone (TSH). Crude acid extracts of stalk-median eminence had variable effects on the release of these hormones. Some extracts enhanced GH release while having a minimal effect on TSH release; others had the reverse effect. Stimulation of adenyl cyclase activity paralleled TSH release, but not GH release. In addition, during short incubations dibutyryl cyclic AMP and inhibitors of phosphodiesterase activity had no effect on GH release, but enhanced TSH release. Other cyclic nucleotides did not stimulate the release of either hormone. Prostaglandin E1 stimulated GH and TSH release as well as adenyl cyclase activity. These results suggest that the mechanisms controlling GH and TSH release differ, and that cyclic AMP may not be involved in GH release.