Episodic GH secretion: evidence for a hypothalamic dopaminergic mechanism.

Abstract

With the development of specific radioimmunoassays for human anterior pituitary (AP) hormones, it became apparent that concentrations of the various hormones in random blood samples often varied widely. It was subsequently recognized by frequent sampling, that blood levels of the AP hormones fluctuated abruptly. This phenomenon, originally described for growth hormone (GH) and adrenocorticotrophic hormone (ACTH) is also demonstrated by other AP hormones, and is presumed to be due to intermittent rather than continuous hormonal secretion. Abrupt changes in hormonal clearance rate, peripheral storage, or excretion which might contribute to such a phenomenon have not been sought extensively, but would appear to be unlikely factors.