AJP - Endocrinology and Metabolism, Vol 265, Issue 2 E203-E209, Copyright © 1993 by American Physiological Society
Effect of hypophysectomy on plasma catecholamines and enkephalins in fetal sheep
C. L. Coulter, I. R. Young, G. Simonetta and I. C. McMillen
Department of Physiology, Monash University, Clayton, Victoria, Australia.
The aim of this study was to determine the effect of fetal hypophysectomy
on the plasma concentrations of catecholamines and enkephalins in the fetal
sheep between 120 and 140 days gestation under basal and hypoxic
conditions. During basal conditions, there was no difference in the plasma
concentrations of norepinephrine and epinephrine between intact and
hypophysectomized groups. Fetal plasma norepinephrine concentrations were
significantly increased during hypoxia in intact fetal sheep (7.2 +/- 2.2
pmol/ml, -15 min; 20.2 +/- 7.7 pmol/ml, 30 min) between 130 and 140 days,
but after fetal hypophysectomy there was no significant norepinephrine
response to hypoxia at this gestational age (4.7 +/- 1.3 pmol/ml, -15 min;
8.8 +/- 2.8 pmol/ml, 30 min). In contrast, fetal plasma epinephrine
concentrations were significantly increased during hypoxia in both the
intact (1.5 +/- 0.5 pmol/ml, -15 min; 3.3 +/- 1.7 pmol/ml, 30 min) and
hypophysectomized groups (1.8 +/- 0.6 pmol/ml, -15 min; 6.8 +/- 4.1
pmol/ml, 30 min) between 130 and 140 days. During basal conditions, plasma
concentrations of free Met-Enk were significantly less in hypophysectomized
fetal sheep (170.8 +/- 34.3 pg/ml; 120-140 days) than in intact fetal sheep
(305.6 +/- 47.3 pg/ml). There were no differences, however, in the fetal
plasma concentrations of total Met-Enk between the intact (18.0 +/- 1.9
ng/ml) and hypophysectomized (16.9 +/- 2.6 ng/ml) groups. During hypoxia,
there were no changes in the fetal plasma concentrations of either free or
total Met-Enk in the intact or hypophysectomized groups.(ABSTRACT TRUNCATED
AT 250 WORDS)
