Endocrinology, Vol 125, 1161-1167, Copyright © 1989 by Endocrine Society

ARTICLES

Abnormalities in the hypothalamo-pituitary-adrenal axis in spontaneously hypertensive rats during development of hypertension

K Hashimoto, S Makino, R Hirasawa, T Takao, M Sugawara, K Murakami, K Ono and Z Ota
Third Department of Internal Medicine, Okayama University Medical School, Japan.

Abnormalities in the hypothalamo-pituitary-adrenal axis in spontaneously hypertensive rats (SHR) during development of hypertension were investigated using in vivo and in vitro methods. Plasma ACTH responses to hemorrhage and ether stress were significantly smaller in 7-week-old SHR than in age-matched Wistar-Kyoto rats (WKY), while plasma corticosterone baseline levels and its response to stress were greater in SHR than in WKY. There was no significant difference in the plasma ACTH response to ether stress between bilaterally adrenalectomized SHR and WKY replaced with a 25% corticosterone pellet for 6 days. Adrenalectomy prevented the development of hypertension in SHR; however, corticosterone replacement restored hypertension. Plasma ACTH showed a smaller response to iv CRH injection in SHR than in WKY, while the ACTH response to arginine vasopressin was not different between SHR and WKY. CRH concentrations in the median eminence, posterior pituitary, and cerebral cortex were lower in SHR than in WKY, while the CRH concentration in the median eminence was not different in SHR and WKY when they were adrenalectomized with or without corticosterone replacement. Basal in vitro CRH release from hypothalamic tissue was reduced in SHR, while CRH release in response to 56 mM KCl was not different in SHR and WKY. These results suggest that adrenocortical function is enhanced in young SHR, that reduced ACTH response to stress and exogenous CRH in SHR may be ascribed to higher plasma corticosterone levels, and that corticosterone is essential for the development of hypertension in SHR.

This article has been cited by other articles:

				K. T. Higa-Taniguchi, F. C. P. Silva, H. M. V. Silva, L. C. Michelini, and J. E. Stern Exercise training-induced remodeling of paraventricular nucleus (nor)adrenergic innervation in normotensive and hypertensive rats Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2007; 292(4): R1717 - R1727. [Abstract] [Full Text] [PDF]

				J. Quadrilatero and J. W. E. Rush Increased DNA fragmentation and altered apoptotic protein levels in skeletal muscle of spontaneously hypertensive rats J Appl Physiol, October 1, 2006; 101(4): 1149 - 1161. [Abstract] [Full Text] [PDF]

				A. G. Bechtold and D. A. Scheuer Glucocorticoids act in the dorsal hindbrain to modulate baroreflex control of heart rate Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2006; 290(4): R1003 - R1011. [Abstract] [Full Text] [PDF]

				D. A. Scheuer, A. G. Bechtold, S. S. Shank, and S. F. Akana Glucocorticoids act in the dorsal hindbrain to increase arterial pressure Am J Physiol Heart Circ Physiol, January 1, 2004; 286(1): H458 - H467. [Abstract] [Full Text] [PDF]

				F. Aguilar, M. Lo, B. Claustrat, J. M. Saez, J. Sassard, and J. Y. Li Hypersensitivity of the Adrenal Cortex to Trophic and Secretory Effects of Angiotensin II in Lyon Genetically-Hypertensive Rats Hypertension, January 1, 2004; 43(1): 87 - 93. [Abstract] [Full Text] [PDF]

				S. S. Shank and D. A. Scheuer Glucocorticoids reduce responses to AMPA receptor activation and blockade in nucleus tractus solitarius Am J Physiol Heart Circ Physiol, May 1, 2003; 284(5): H1751 - H1761. [Abstract] [Full Text] [PDF]

				D. A. Scheuer and S. W. Mifflin Glucocorticoids modulate baroreflex control of renal sympathetic nerve activity Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2001; 280(5): R1440 - R1449. [Abstract] [Full Text] [PDF]

				B. K. Taylor, R. E. Roderick, E. St. Lezin, and A. I. Basbaum Hypoalgesia and hyperalgesia with inherited hypertension in the rat Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2001; 280(2): R345 - R354. [Abstract] [Full Text] [PDF]

				H. Suzuki, F. A. Delano, N. Jamshidi, D. Katz, M. Mori, K. Kosaki, R. A. Gottlieb, H. Ishii, and G. W. Schmid-Schonbein Enhanced DNA fragmentation in the thymus of spontaneously hypertensive rats Am J Physiol Heart Circ Physiol, June 1, 1999; 276(6): H2135 - H2140. [Abstract] [Full Text] [PDF]

				F. Gomez, E. R. De Kloet, and A. Armario Glucocorticoid negative feedback on the HPA axis in five inbred rat strains Am J Physiol Regulatory Integrative Comp Physiol, February 1, 1998; 274(2): R420 - R427. [Abstract] [Full Text] [PDF]

				S. Komatsu, J. Panes, J. M. Russell, D. C. Anderson, V. R. Muzykantov, M. Miyasaka, and D. N. Granger Effects of Chronic Arterial Hypertension on Constitutive and Induced Intercellular Adhesion Molecule-1 Expression In Vivo Hypertension, February 1, 1997; 29(2): 683 - 689. [Abstract] [Full Text]

				H. Suzuki, B. W. Zweifach, and G. W. Schmid-Schonbein Glucocorticoid Modulates Vasodilator Response of Mesenteric Arterioles in Spontaneously Hypertensive Rats Hypertension, January 1, 1996; 27(1): 114 - 118. [Abstract] [Full Text]