AJP - Regulatory, Integrative and Comparative Physiology, Vol 250, Issue 3 365-R369, Copyright © 1986 by American Physiological Society
Endogenous hormones and regulation of uterine blood flow during pregnancy
D. Caton and P. S. Kalra
Fourteen pregnant sheep were prepared for measurements of blood flow
through a major uterine artery (UBF) and of arterial concentrations of
estrone, estradiol, and progestagen. Five of the animals were
ovariectomized. Measurements were made daily (n = 12) or every 4 h for 24 h
(n = 4). Statistically significant (P less than 0.01) correlation
coefficients were detected between UBF and hormone, either alone or in
combination; the closest and most consistent associations were those in
which estrogen and progestagen concentrations were summed or multiplied.
Ewes with higher hormonal concentrations were those that had the higher
rates of UBF. Correlation coefficients were statistically significant more
often among ovariectomized animals. No associations were detected within
one animal that delivered a growth-retarded fetus nor from any of the 24-h
data. Estrogens and progestagen accounted for as much as 25% of the daily
variation of UBF among and within sheep during the last half of pregnancy.
