Failure of growth hormone (GH) to feed back at the level of the pituitary to alter the response of the somatotrophs to GH-releasing factor.

GH feeds back at the level of the central nervous system to alter the release of somatostatin and GRF, resulting in altered GH release. The purpose of this study was to see whether the concentration of GH, impinging directly on the somatotrophs of the adenohypophysis, would alter the responsiveness of the somatotrophs to GRF. Using a perifusion system and dispersed pituitary cells, we found that the GH response to a pulse of GRF is unaltered over a wide range of GH concentrations. We conclude that GH does not feed back at the level of the adenohypophysis to alter the responsiveness of the somatotrophs to GRF.