AJP - Endocrinology and Metabolism, Vol 268, Issue 1 E28-E32, Copyright © 1995 by American Physiological Society
Effect of corticosteroids on free and sulfoconjugated catecholamines at birth in premature newborn sheep
H. M. Stein, A. Martinez, K. Oyama, L. Blount and J. F. Padbury
Department of Pediatrics, Georgetown University Medical Center, Washington, District of Columbia 20007.
We previously demonstrated that prenatal corticosteroids attenuated the
expected exponential increase in circulating catecholamines at birth. The
present studies were undertaken to determine if alteration in
sulfoconjugation could account for this attenuation. Catheterized fetal
lambs received saline (n = 6) or corticosteroids (n = 8) intravenously for
60 h. The lambs were delivered by cesarean section at 130 +/- 1 days
gestation. Ventilatory and cardiovascular responses and plasma
catecholamine concentrations were measured for 2 h after birth. Although
plasma free catecholamines levels were higher in controls than in
corticosteroid-treated fetuses, the sulfoconjugated levels were similar in
the two groups. Thus the corticosteroid-treated fetuses had a higher
proportion of plasma sulfoconjugated catecholamines consistent with the
possibility that sulfoconjugation was augmented during intrauterine life.
After birth, the corticosteroid-treated animals showed an attenuated
increase in plasma free catecholamine levels compared with controls but a
similar increase in sulfoconjugated catecholamine levels to the control
animals. The proportion of plasma sulfoconjugated catecholamines was higher
in the corticosteroid-treated animals; however, the increase in
sulfoconjugated catecholamines was insufficient to account for the
attenuated overall increase in total catecholamines in the
corticosteroid-treated animals.
