Responsiveness of Intermediate Lobe Cells to Neural Mediators in Culture

Summary

Immunologically and biologically active ACTH, as well as biologically active α-MSH were secreted by monolayer cultures of rat pituitary intermediate lobe cells. The release of the immunoreactive ACTH and the bioactive a-MSH was inhibited by dopamine and by the dopamine agonist bromocriptine. The inhibition is probably mediated by specific dopaminergic receptors, since simultaneously added haloperidol prevented the dopamine induced hormone release inhibition. Pro-Leu-Gly-NH₂, a potent inhibitor of the α-MSH secretion, had no effect on the release of ACTH. Synthetic ovine CRF stimulated the release of both immunoreactive ACTH and bioactive α-MSH in dose-dependent fashion. Corticosterone was without effect on hormone release in the cultures derived from both adrenalectomized and sham-operated animals.

Key words

Pars intermedia - cell culture - ACTH - MSH - dopamine