Endocrine Abstracts

Pituitary hormones are released into the bloodstream in a pulsatile fashion in response to stimuli from their hypothalamic regulators. For efficient generation of hormone pulses, both the hypothalamic mechanisms and the pituitary target cells must exhibit a high degree of coordinated secretory activity. This is particularly important for the growth hormone (GH) axis since the target tissue responses are critically dependent on the temporal pattern of GH exposure, as well as th...

Animal and clinical models of GHRH excess suggest that GHRH provides an important trophic drive to pituitary somatotrophs. Mice in which GHRH neurons have been ablated using a novel viral ion channel transgene (GHRH-M2 mice) show marked anterior pituitary hypoplasia and GH deficiency although GH cells are present. GHRH-M2 mice are also deficient in prolactin which is surprising as GHRH has little or no direct effect on PRL synthesis or release (Le Tissier, Mol Endo 19). In mic...