Endocrine effects of ventilation, oxygenation and cord occlusion in near-term fetal sheep

F G Smith; B A Smith; J L Segar; J E Robillard

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Journal article

Endocrine effects of ventilation, oxygenation and cord occlusion in near-term fetal sheep

F G Smith, B A Smith, J L Segar and J E Robillard

Journal of developmental physiology, Vol.15(3), pp.133-138

03/01/1991

PMID: 1834728

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Abstract

The transition from fetal to newborn life is associated with significant endocrine changes. Some of these changes may be triggered by the effects of spontaneous respiration, increased oxygenation and removal of the placental circulation at birth. We, therefore, studied endocrine function during in utero ventilation, oxygenation and cord occlusion, in nine chronically-instrumented fetal sheep aged 137 to 140 days of gestation. During the sequential effects of in utero ventilation and oxygenation, plasma renin activity (PRA) and angiotensin II (AII) remained at control levels of 6.3 +/- 1.9 ng/ml per h and 66 +/- 15 pg/ml. After cord occlusion, PRA increased to 10.3 +/- 2.2 ng/ml per hr and AII increased to 86 +/- 24 pg/ml, the latter being non-significant. Plasma cortisol levels also increased from control levels of 3.5 +/- 1.0 to 6.7 +/- 0.8 g/dl during cord occlusion (P = 0.02). During the sequential effects of ventilation, oxygenation and cord occlusion, plasma epinephrine increased from control levels of 87 +/- 17 to 492 +/- 142 pg/ml (P = 0.04), and plasma norepinephrine levels increased slightly from 620 +/- 112 to 850 +/- 214 pg/ml. These data provide evidence that many of the changes in endocrine function seen at birth result from factors other than spontaneous respiration, oxygenation and umbilical cord occlusion.

Pregnancy

Air

Angiotensin II - blood

Animals

Arginine Vasopressin - blood

Atrial Natriuretic Factor - blood

Blood Gas Analysis - veterinary

Blood Pressure

Carbon Dioxide - blood

Dopamine - blood

Endocrine Glands - physiology

Epinephrine - blood

Female

Fetus - physiology

Heart Rate, Fetal

Hydrocortisone - blood

Hydrogen-Ion Concentration

Norepinephrine - blood

Oxygen - blood

Oxygen - pharmacology

Renin - blood

Sheep - embryology

Umbilical Cord - physiology

Details

Title: Subtitle: Endocrine effects of ventilation, oxygenation and cord occlusion in near-term fetal sheep
Creators: F G Smith - University of Iowa
B A Smith
J L Segar
J E Robillard
Resource Type: Journal article
Publication Details: Journal of developmental physiology, Vol.15(3), pp.133-138
PMID: 1834728
ISSN: 0141-9846
Grant note: HD-20576 / NICHD NIH HHS HL-14388 / NHLBI NIH HHS DK-38302 / NIDDK NIH HHS
Language: English
Date published: 03/01/1991
Academic Unit: Molecular Physiology and Biophysics; Nephrology, Dialysis and Transplantation; Stead Family Department of Pediatrics; Medicine Administration
Record Identifier: 9984774212502771

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