Jm. Bassett et C. Hanson, CATECHOLAMINES INHIBIT GROWTH IN FETAL SHEEP IN THE ABSENCE OF HYPOXEMIA, American journal of physiology. Regulatory, integrative and comparative physiology, 43(6), 1998, pp. 1536-1545
To evaluate contributions of catecholamines to inhibition of growth du
ring chronic hypoxemia or severe undernutrition, epinephrine (Epi; 0.2
5-0.35 mu g.kg(-1).min(-1)) or norepinephrine (NE; 0.5-0.7 mu g.kg(-1)
.min(-1)) was administered to normoxemic fetuses in twin-pregnant ewes
for 8-12 days, from 125 to 127 days of gestation. Both had similar ef
fects and decreased fetal weight by similar to 20% relative to control
twins (P < 0.01). Weight gain ceased during infusion of Epi or NE (-2
1 +/- 14.8 or 14 +/- 20.9 g/day), whereas controls gained 93 +/- 13.2
g/day (P < 0.01). Effects on tissues and organs varied, spleen and thy
mus being most retarded, whereas brain weight and skeletal measures we
re affected little. Selected muscles from infused fetuses weighed 72%
of those in controls. Growth ceased during infusion (P < 0.001). Weigh
t gain of hindlimb bones was negligible, but length increased at 56% o
f control rates. Arterial blood CO2 and plasma insulin were decreased
(P < 0.001), but plasma glucose, growth hormone, and blood oxygenation
increased (P < 0.001). Actions of Epi and NE could underlie asymmetri
cal growth retardation occurring in many adverse physiological situati
ons during fetal development.