AJP - Regulatory, Integrative and Comparative Physiology, Vol 268, Issue 3 614-R624, Copyright © 1995 by American Physiological Society
Sex hormone modulation of flow velocity in the parametrial artery of the pregnant rat
G. I. Gorodeski, L. A. Sheean and W. H. Utian
Department of Reproductive Biology, Case Western Reserve University, Cleveland, Ohio.
The objective of the study was to correlate the disparate distal/proximal
state of maturation of uterine segments in the rat with the hemodynamics of
the parametrial uterine artery. Flow velocity was determined by the
methylene blue photometric analysis. In nonpregnant animals, the velocity
in the distal (VD-->P) and proximal (VP-->D) portions of the
parametrial artery were similar, but in late pregnancy, VD-->P was
higher than VP-->D. The difference was associated with an increased
width of the distal part of the parametrial artery. In addition, the
distance from the proximal end of the parametrial artery where the D-->P
and P-->D streams collided decreased in animals in late pregnancy,
compared with nonpregnant animals. Treatment with estradiol and RU-486
reversed the pregnancy-related hemodynamic changes. The pregnancy-related
shift in flow velocity in the parametrial artery is crucial to rat fetal
survival in utero and may be a mechanism in vivo for promoting maturation
of distal, compared with proximal, segments of the uterine horn.
