HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 287/1/R209    most recent 00701.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (10) Citing Articles via Google Scholar Google Scholar Articles by Adachi, K. Articles by Ducsay, C. A. Search for Related Content PubMed PubMed Citation Articles by Adachi, K. Articles by Ducsay, C. A.

DEVELOPMENT AND TISSUE PLASTICITY

Long-term hypoxia alters ovine fetal endocrine and physiological responses to hypotension

¹Departments of Physiology/Pharmacology and ²Pediatrics, School of Medicine, Center for Perinatal Biology, Loma Linda University, Loma Linda, California 92350

Submitted 8 December 2003 ; accepted in final form 8 March 2004

Exposure to long-term hypoxia (LTH) results in altered cortisol responses in the ovine fetus. The present study was designed to test the hypothesis that LTH alters adrenal responsiveness to fetal hypotension. Pregnant ewes were maintained at high altitude (3,820 meters) from day 30 of gestation. Normoxic control and LTH fetuses were catheterized on day 132 of gestation. In the LTH group, maternal PO₂ was maintained comparable to that observed at altitude (60 mmHg) by nitrogen infusion through a tracheal catheter. On day 137, fetuses received a 5-h saline infusion followed by infusion of sodium nitroprusside to reduce fetal arterial pressure by 30–35% for 10 min. The study was repeated on day 139 of gestation with a continuous cortisol infusion (10 µg/min). Hypothalamic and pituitary tissues were collected from additional fetuses for assessment of glucocorticoid receptors. During the saline infusion in response to hypotension, plasma ACTH increased over preinfusion mean values in both groups (P < 0.05). Plasma cortisol concentrations increased in both groups concomitant with increased ACTH secretion. However, peak values in the LTH fetuses were significantly higher compared with controls (P < 0.05). During the cortisol infusion, the ACTH response was eliminated in both groups, with ACTH levels significantly lower in the LTH group (P < 0.05). Glucocorticoid receptor binding was not different between groups. These results demonstrate an enhanced cortisol response to hypotension in LTH fetuses that does not appear to be the result of an increase in negative feedback sensitivity of the hypothalamic-pituitary-adrenal axis.

adrenocorticotropin hormone; cortisol; nitroprusside

This article has been cited by other articles:

				C. A. Ducsay, M. Mlynarczyk, K. M. Kaushal, K. Hyatt, K. Hanson, and D. A. Myers Long-term hypoxia enhances ACTH response to arginine vasopressin but not corticotropin-releasing hormone in the near-term ovine fetus Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2009; 297(3): R892 - R899. [Abstract] [Full Text] [PDF]

				C. E. Wood, M. Powers Fraites, and M. Keller-Wood Blockade of PGHS-2 inhibits the hypothalamus-pituitary-adrenal axis response to cerebral hypoperfusion in the sheep fetus Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2009; 296(6): R1813 - R1819. [Abstract] [Full Text] [PDF]

				B. Root, J. Abrassart, D. A. Myers, T. Monau, and C. A. Ducsay Expression and Distribution of Glucocorticoid Receptors in the Ovine Fetal Adrenal Cortex: Effect of Long-term Hypoxia Reproductive Sciences, May 1, 2008; 15(5): 517 - 528. [Abstract] [PDF]

				D. A. Myers, K. Hanson, M. Mlynarczyk, K. M. Kaushal, and C. A. Ducsay Long-term hypoxia modulates expression of key genes regulating adipose function in the late-gestation ovine fetus Am J Physiol Regulatory Integrative Comp Physiol, April 1, 2008; 294(4): R1312 - R1318. [Abstract] [Full Text] [PDF]

				C. A. Ducsay, K. Hyatt, M. Mlynarczyk, B. K. Root, K. M. Kaushal, and D. A. Myers Long-term hypoxia modulates expression of key genes regulating adrenomedullary function in the late gestation ovine fetus Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2007; 293(5): R1997 - R2005. [Abstract] [Full Text] [PDF]

				C. A. Ducsay, K. Hyatt, M. Mlynarczyk, K. M. Kaushal, and D. A. Myers Long-term hypoxia increases leptin receptors and plasma leptin concentrations in the late-gestation ovine fetus Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2006; 291(5): R1406 - R1413. [Abstract] [Full Text] [PDF]

				D. A. Myers, K. Hyatt, M. Mlynarczyk, I. M. Bird, and C. A. Ducsay Long-term hypoxia represses the expression of key genes regulating cortisol biosynthesis in the near-term ovine fetus Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2005; 289(6): R1707 - R1714. [Abstract] [Full Text] [PDF]

				D. A. Myers, P. A. Bell, K. Hyatt, M. Mlynarczyk, and C. A. Ducsay Long-term hypoxia enhances proopiomelanocortin processing in the near-term ovine fetus Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2005; 288(5): R1178 - R1184. [Abstract] [Full Text] [PDF]