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AJP - Regulatory, Integrative and Comparative Physiology, Vol 265, Issue 4 858-R862, Copyright © 1993 by American Physiological Society
ARTICLES |
C. E. Wood, T. A. Cudd, C. Kane and K. Engelke
Department of Physiology, University of Florida College of Medicine, Gainesville 32610-0274.
This study was performed to test the hypothesis that thromboxane A2 stimulates increases in fetal adrenocorticotropic hormone (ACTH), vasopressin, or renin secretion and affects fetal cardiovascular function by an action on the fetal central nervous system. We infused a stable synthetic analogue of thromboxane A2, U-46619, into one common carotid artery or inferior vena cava or infused saline into one common carotid artery in chronically catheterized fetal sheep between 127 and 140 days gestation. We found that intracarotid but not intravenous infusions of U-46619 at a rate of 750 ng/min stimulated increases in fetal plasma ACTH concentration. Infusions of U-46619 at both sites increased fetal blood pressure; the infusion into the carotid arterial blood produced a more rapid increase in blood pressure and a significant decrease in central venous pressure. None of the infusions altered plasma vasopressin concentration or plasma renin activity, blood gases, hematocrit, or plasma cortisol concentration. We conclude that thromboxane A2 stimulates fetal ACTH, but not vasopressin or renin, secretion via an action within the area perfused by carotid arterial blood. Thromboxane A2 increases blood pressure via an action at the fetal central nervous system, as well as via a direct vasoconstrictor action in the systemic circulation.
This article has been cited by other articles:
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M. Keller-Wood and C. E. Wood Regulation of maternal ACTH in ovine pregnancy: does progesterone play a role? Am J Physiol Endocrinol Metab, October 1, 2008; 295(4): E913 - E920. [Abstract] [Full Text] [PDF] |
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F. Li, C. E. Wood, and M. Keller-Wood Adrenalectomy alters regulation of blood pressure and endothelial nitric oxide synthase in sheep: modulation by estradiol Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2007; 293(1): R257 - R266. [Abstract] [Full Text] [PDF] |
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E. Jensen, C. E. Wood, and M. Keller-Wood Chronic alterations in ovine maternal corticosteroid levels influence uterine blood flow and placental and fetal growth Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2005; 288(1): R54 - R61. [Abstract] [Full Text] [PDF] |
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M. Keller-Wood and C. E. Wood Pregnancy alters cortisol feedback inhibition of stimulated ACTH: studies in adrenalectomized ewes Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2001; 280(6): R1790 - R1798. [Abstract] [Full Text] [PDF] |
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C. E. Wood and H. Tong Central nervous system regulation of reflex responses to hypotension during fetal life Am J Physiol Regulatory Integrative Comp Physiol, December 1, 1999; 277(6): R1541 - R1552. [Abstract] [Full Text] [PDF] |
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H. Tong and C. E. Wood Indomethacin attenuates the cerebral blood flow response to hypotension in late-gestation fetal sheep Am J Physiol Regulatory Integrative Comp Physiol, November 1, 1999; 277(5): R1268 - R1273. [Abstract] [Full Text] [PDF] |
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H. Tong, F. Lakhdir, and C. E. Wood Endogenous prostanoids modulate the ACTH and AVP responses to hypotension in late-gestation fetal sheep Am J Physiol Regulatory Integrative Comp Physiol, September 1, 1998; 275(3): R735 - R741. [Abstract] [Full Text] [PDF] |
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M. Keller-Wood ACTH responses to CRF and AVP in pregnant and nonpregnant ewes Am J Physiol Regulatory Integrative Comp Physiol, June 1, 1998; 274(6): R1762 - R1768. [Abstract] [Full Text] [PDF] |
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T. A. Cudd Thromboxane A2 acts on the brain to mediate hemodynamic, adrenocorticotropin, and cortisol responses Am J Physiol Regulatory Integrative Comp Physiol, May 1, 1998; 274(5): R1353 - R1360. [Abstract] [Full Text] [PDF] |
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M. Keller-Wood ACTH responses to hypotension and feedback inhibition of ACTH increased by chronic progesterone treatment Am J Physiol Regulatory Integrative Comp Physiol, January 1, 1998; 274(1): R81 - R87. [Abstract] [Full Text] [PDF] |
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