AJP - Endocrinology and Metabolism, Vol 247, Issue 5 693-E697, Copyright © 1984 by American Physiological Society
Enhancement of adrenomedullary catecholamine release by adrenal cortex in fetus
C. Y. Cheung
Catecholamines (CA) release from ovine fetal adrenomedullary cells was
greatly enhanced by coincubation with adrenocortical cells. Total CA
release was significantly elevated at 2 and 6 h of preincubation by seven-
and twofold, respectively. With continuous coincubation of the two cell
types, the enhancement of release was found to occur as early as 30 min and
maintained for at least 6 h. A similar enhancement effect was observed when
adrenomedullary cells were incubated in adrenocortical cell incubation
medium (ACM). The stimulation of release was demonstrated for each of the
three CA: dopamine, norepinephrine, and epinephrine. The effect of
adrenocortical cells differed from that of adrenal steroids, because
cortisol selectively stimulated the release of epinephrine only by one- to
threefold after a latency of 6 to 9 h, whereas dehydroepiandrosterone had
no effect on the release of the three CA at any time tested. Finally, the
CA stimulatory activity in ACM was acid and heat stable, not extractable by
ether but inactivated by proteolytic digestion. These results suggest that
the adrenal cortex of the near-term ovine fetus secretes a factor that
stimulates the release and perhaps synthesis of CA from the adrenal
medulla.
