Se. Oberfield et al., ALTERED SENSITIVITY TO LOW-DOSE DEXAMETHASONE IN A SUBSET OF PATIENTSWITH PREMATURE ADRENARCHE, The Journal of clinical endocrinology and metabolism, 79(4), 1994, pp. 1102-1104
During adrenarche, levels of adrenal androgens increase. Although the
regulatory mechanisms of adrenarche and premature adrenarche (PA) are
not fully understood, it has been suggested that, unlike the cortisol
(F) response to glucocorticoid suppression, which is not age dependent
, before adrenarche the major adrenal androgen, dehydroepiandrosterone
sulfate, is not suppressible by glucocorticoid. As these studies were
performed using long term, high dose glucocorticoids, we sought to ev
aluate the F and adrenal androgen or androgen precursor suppression in
response to low dose glucocorticoids [a single evening dose of dexame
thasone (DEX), 0.3 mg/m(2)]. Twenty-four children (aged 1.3-8.75 yr; 4
males and 20 females) known to have PA, as determined by their respon
se to ACTH-(1-24) (Cortrosyn; 0.25 mg, given by iv bolus), were studie
d The children with PA could be divided into two groups, as defined by
their morning F level after DEX administration: group I (n = 12), F l
evels below 5 mu g/dL; and group II (n = 12), F levels of 5 mu g/dL or
more. Although the mean baseline values of F, testosterone, dehydroep
iandrosterone, Delta(4)-androstenedione, 17-hydroxyprogesterone, and D
elta(5)-17-hydroxypregnenolone did not differ between groups I and II,
the mean levels in group I vs. group II of dehydroepiandrosterone, De
lta(4)-androstenedione, and Delta(5)-17-hydroxypregnenolone were signi
ficantly greater in response to ACTH and lower in response to DEX (P <
0.05). Although no clinical difference was noted between the 2 groups
, the mean so for bone age adjusted for chronological age was greater
and approached significance in group I, suggesting a greater degree of
biological maturity in this group. These results suggest an increased
sensitivity of the hypothalamic-pituitary-adrenal axis to changes in
ACTH secretion in this subgroup of patients with PA.