Endocrinology, Vol 127, 2085-2089, Copyright © 1990 by Endocrine Society

ARTICLES

Arginine vasopressin and corticotropin releasing factor: binding to ovine anterior pituitary membranes

PJ Shen, IJ Clarke, BJ Canny, JW Funder and AI Smith
Prince Henry's Institute of Medical Research, Prince Henry's Hospital, Melbourne, Australia.

In the sheep, in contrast to the rat, arginine vasopressin (AVP) is a more potent stimulus to ACTH secretion from the anterior pituitary (AP) than CRF. To further explore this difference, we have compared [3H]AVP and [125I]-[Nle21 Tyr32]ovine CRF binding in membranes prepared from rat and sheep AP. Between species, no difference in affinity of binding was found for either ligand. In contrast, the concentration of AVP receptors in sheep AP was twice that in rat, whereas that of CRF receptors was only one tenth. AVP receptor concentration in sheep AP was not altered by chronic (10 day) dexamethasone administration, but fell to 60% of control after chronic (60 day) hypothalamo-pituitary- disconnection. The increased level of AVP receptors and the much lower level of CRF receptors in sheep compared with rat may thus provide an explanation for our previous findings of increased sensitivity to AVP and a very poor response to CRF in stimulating ACTH release from the sheep AP. In addition the finding that AVP receptor numbers are reduced in the hypothalamo-pituitary-disconnected sheep suggests that hypothalamic factors may play a role in regulating AVP receptor concentration in the ovine AP gland.

This article has been cited by other articles:

				J. L. Green, J. P. Figueroa, G. A. Massmann, J. Schwartz, and J. C. Rose Corticotropin-Releasing Hormone Type I Receptor Messenger Ribonucleic Acid and Protein Levels in the Ovine Fetal Pituitary: Ontogeny and Effect of Chronic Cortisol Administration Endocrinology, August 1, 2000; 141(8): 2870 - 2876. [Abstract] [Full Text] [PDF]

				D. Engler, E. Redei, and I. Kola The Corticotropin-Release Inhibitory Factor Hypothesis: A Review of the Evidence for the Existence of Inhibitory as Well as Stimulatory Hypophysiotropic Regulation of Adrenocorticotropin Secretion and Biosynthesis Endocr. Rev., August 1, 1999; 20(4): 460 - 500. [Abstract] [Full Text] [PDF]

				F. M. Perez, J. Schwartz, and J. C. Rose Developmental Changes in Ovine Corticotrophs in Vitro Endocrinology, March 1, 1997; 138(3): 916 - 921. [Abstract] [Full Text] [PDF]