AJP - Regulatory, Integrative and Comparative Physiology, Vol 262, Issue 6 1121-R1130, Copyright © 1992 by American Physiological Society

ARTICLES

Models of neurohypophyseal homeostasis

M. D. Fitzsimmons, M. M. Roberts, T. G. Sherman and A. G. Robinson
Department of Medicine, University of Pittsburgh, Pennsylvania 15261.

Rats subject to prolonged (3-6 days) hypernatremia show significantly decreased pituitary vasopressin content as well as increased levels of hypothalamic vasopressin mRNA; these values return to baseline levels after the stimulus is removed. In this paper, we tested whether a single cellular mechanism for regulation of synthesis could account for the experimental observations of both pituitary hormone depletion-repletion and hypothalamic mRNA content. We developed several "minimal" models of vasopressin synthesis in which control of hormone synthesis was regulated exclusively by transcription, translation, or mRNA decay and tested each model to see which best emulated the dynamics of neuro-hypophyseal vasopressin content and hypothalamic vasopressin mRNA. Experimental data provided parameters for pituitary content, baseline and stimulated release rates, mRNA decay, transcription, and translation. Models based exclusively on translation and mRNA decay failed to produce predictions similar to experimental observations. Of the models tested, the transcription model provided predictions most consistent with laboratory data, although some quantitative differences remain. The results of the computer modeling strongly suggest that transcription represents the predominant means by which magnocellular neurons regulate vasopressin synthesis.

This article has been cited by other articles:

				J. P. H. Burbach, S. M. Luckman, D. Murphy, and H. Gainer Gene Regulation in the Magnocellular Hypothalamo-Neurohypophysial System Physiol Rev, July 1, 2001; 81(3): 1197 - 1267. [Abstract] [Full Text] [PDF]

				J. A. Maurer and S. Wray Luteinizing Hormone-Releasing Hormone (LHRH) Neurons Maintained in Hypothalamic Slice Explant Cultures Exhibit a Rapid LHRH mRNA Turnover Rate J. Neurosci., December 15, 1997; 17(24): 9481 - 9491. [Abstract] [Full Text] [PDF]