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) 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 PubMed Alert me to new issues of the journal My Folders Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Young, S. F. Articles by Rose, J. C. Search for Related Content PubMed PubMed Citation Articles by Young, S. F. Articles by Rose, J. C. Agricola Articles by Young, S. F. Articles by Rose, J. C.

Attenuation of Corticotropin-Releasing Hormone and Arginine Vasopressin Responsiveness During Late-Gestation Pregnancy in Sheep¹

^a Department of Physiology/Pharmacology ^b Department of Obstetrics/Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157

Responsiveness of the hypothalamo-pituitary-adrenal axis is decreased during pregnancy. Therefore, the objective of the present study was to determine if responsiveness at the level of individual corticotrophs to corticotropin-releasing hormone (CRH) or arginine vasopressin (AVP) is decreased during pregnancy in sheep. Anterior pituitaries (APs) were collected from pregnant and nonpregnant ewes. Half of the APs were dispersed, and cells were placed on immobilon and treated with vehicle, CRH (10 nM), or AVP (100 nM) for 2 h. Cells were then fixed and incubated with ACTH or pro-opiomelanocortin (POMC) antibodies. The percentage of cells staining positive for immunoreactive (ir) ACTH or POMC, the percentage of cells secreting irACTH or POMC, and the area of irACTH or POMC secretion were measured. RNA was extracted from the other half of the APs to quantify CRH type 1 (CRH-R1) and vasopressin type 1b (V1b) receptor mRNA by ribonuclease protection assay. CRH treatment increased the percentage of corticotrophs with relatively large areas of irACTH and POMC secretion in nonpregnant, but not in pregnant, ewes. AVP treatment significantly increased the percentage of irACTH- and POMC-secreting cells in nonpregnant, but not in pregnant, ewes. V1b receptor mRNA, but not CRH-R1 receptor mRNA, was significantly decreased during pregnancy. These results suggest that corticotroph responsiveness to CRH and AVP is decreased during pregnancy in sheep. Therefore, reduced corticotroph responsiveness may contribute to stress hyporesponsivity during pregnancy.

First decision: 31 October 2001.

¹ Supported by National Institutes of Health grant HD-11210.

² Correspondence: James C. Rose, Department of Obstetrics/Gynecology, Wake Forest University School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157. FAX: 336 716 6937; jimrose{at}wfubmc.edu

This article has been cited by other articles:

				K. Farrand, I. C. McMillen, S. Tanaka, and J. Schwartz Subpopulations of Corticotrophs in the Sheep Pituitary during Late Gestation: Effects of Development and Placental Restriction Endocrinology, October 1, 2006; 147(10): 4762 - 4771. [Abstract] [Full Text] [PDF]

				S. F. Young, S. B. Tatter, N. K. Valego, J. P. Figueroa, J. Thompson, and J. C. Rose The role of hypothalamic input on corticotroph maturation in fetal sheep Am J Physiol Regulatory Integrative Comp Physiol, June 1, 2003; 284(6): R1621 - R1630. [Abstract] [Full Text] [PDF]

				S. F. Young, J. L. Smith, J. P. Figueroa, and J. C. Rose Ontogeny and effect of cortisol on vasopressin-1b receptor expression in anterior pituitaries of fetal sheep Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2003; 284(1): R51 - R56. [Abstract] [Full Text] [PDF]