Myometrial contracture-related increases in plasma adrenocorticotropin in fetal sheep in the last third of gestation are abolished by maintaining fetal normoxemia

B. R. Woudstra, C. Kim, J. G. Aarnoudse, P. W. Nathanielsz

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Low amplitude, long-lasting epochs of myometrial activity, contractures, occur throughout the majority of pregnancy in all species studied to date. Contractures are associated with a fall in fetal oxygenation and changes in fetal behavioral state. In the present study we observed that contractures produced by the administration of 70 mU oxytocin iv to the pregnant ewe at 125-139 days gestational age (term 145-150 days) result in a fall in fetal carotid arterial PO2 of approximately 2.5 mm Hg and are followed by a rise in fetal carotid arterial plasma ACTH of 16.3 ± 9.6 pg·ml-1 (mean ± SEM). When the contracture-induced fall in fetal arterial PO2 was prevented by administration of oxygen to the ewe, fetal ACTH did not rise after the contracture. In conclusion, these observations demonstrate that the relatively small fall in fetal PO2 that accompanies a contracture can be sensed by the fetus and is an essential part of the stimulus to the increased secretion of fetal ACTH that accompanies a contracture. These findings support the view that myometrial activity is one of the factors that influence fetal ACTH secretion.

Original languageEnglish (US)
Pages (from-to)1709-1713
Number of pages5
JournalEndocrinology
Volume129
Issue number4
DOIs
StatePublished - Oct 1991
Externally publishedYes

ASJC Scopus subject areas

  • Endocrinology

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