AJP - Endocrinology and Metabolism, Vol 241, Issue 4 305-E309, Copyright © 1981 by American Physiological Society
Pubertal endocrinology of the baboon: adrenarche
V. D. Castracane, G. B. Cutler Jr and D. L. Loriaux
The concentration of the adrenal steroids dehydroepiandrosterone (DHA) and
dehydroepiandrosterone sulfate (DHA-S) was measured by radioimmunoassay in
plasma of 134 baboons (Papio cynocephalus) from 0 to 17 yr of age. Plasma
androstenedione (delta 4-A) was also measured in 289 baboons encompassing
the same age range. The concentration of DHA was persistently high from
birth to adulthood, exceeding 700 ng/dl at all ages. This differs markedly
from the human pattern in which DHA concentrations fall below 50 ng/dl
following regression of the fetal adrenal. Plasma DHA-S declined rapidly
during the first 2 yr of life, causing a significant age-related decline in
the ratio of DHA-S:DHA, a pattern not seen in man. Plasma delta 4-A
declined during the first 3 yr, but remained greater than 100 ng/dl. delta
4-A then rose sharply at age 4, the time of gonadal maturation in the
baboon. Thus, the baboon differs from man primarily in the persistent
elevation of plasma DHA and delta 4-A prior to puberty. It remains to be
determined whether this difference reflects fundamentally different
mechanisms regulating adrenal androgen secretion or merely the closer
temporal juxtaposition of fetal adrenal regression and adrenarche due to
the more rapid sexual maturation of the baboon.
