Altered sensitivity to low dose dexamethasone in a subset of patients with premature adrenarche.

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 evaluate the F and adrenal androgen or androgen precursor suppression in response to low dose glucocorticoids [a single evening dose of dexamethasone (DEX), 0.3 mg/m2]. Twenty-four children (aged 1.3-8.75 yr; 4 males and 20 females) known to have PA, as determined by their response to ACTH-(1-24) (Cortrosyn; 0.25 mg, given by iv bolus), were studied. 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 levels below 5 micrograms/dL; and group II (n = 12), F levels of 5 micrograms/dL or more. Although the mean baseline values of F, testosterone, dehydroepiandrosterone, delta 4-androstenedione, 17-hydroxyprogesterone, and delta 5-17-hydroxypregnenolone did not differ between groups I and II, the mean levels in group I vs. group II of dehydroepiandrosterone, delta 4-androstenedione, and delta 5-17-hydroxypregnenolone were significantly 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 SD 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.

Long-term endocrine sequelae after treatment of medulloblastoma: prospective study of growth and thyroid function.

Endocrine evaluations were performed prospectively in 22 patients with medulloblastoma (ages 2 1/2 to 23 1/2 years at diagnosis), after craniospinal radiation with or without adjuvant chemotherapy. The mean craniospinal hypothalamic-pituitary). and thyroid radiation doses were 3600 and 2400 rads, respectively. Fourteen (73%) of 19 patients who had not yet completed their growth experienced a decrease in growth velocity. However, only three of 10 of these children, who underwent growth hormone stimulation tests, had evidence of deficient growth hormone responses, suggesting that growth hormone secretory or regulatory dysfunction, rather than absolute growth hormone deficiency, is present in the majority of these children. Elevated thyroid-stimulating hormone levels were noted in 15 of 22 patients; one patient had hypothalamic hypothyroidism. Thus, the late effects of therapy for medulloblastoma include frequent endocrine morbidity involving hypothalamic-pituitary and thyroid dysfunction.

Recovery of adrenal function after treatment of adrenocortical carcinoma with o,p'-DDD.

The adrenolytic agent, 2,2-bis[2-chlorophenyl-4-chlorophenyl] 1,1 dichloroethane (o,p'-DDD), was used over a 20-month period following surgery in a 2 3/12-year-old girl for treatment of adrenocortical carcinoma. The child remained free of disease and was maintained on glucocorticoid and mineralo-corticoid supplements for 7 years. Hormonal evaluation was undertaken at 9 9/12 years of age to determine remaining adrenal steroidogenic capacity. Following discontinuation of both hydrocortisone and 9 alpha-fludrocortisone, she remained stable and asymptomatic. Immediately after discontinuing 9 alpha-fludrocortisone, the adrenal glomerulosa was able to respond to stimulation by the renin-angiotensin system as shown by the ability to achieve renal sodium conservation on a restricted sodium intake (less than 10 mEq/d for 5 d). The response of the adrenal fasciculata to ACTH stimulation showed a slower recovery. Baseline levels of cortisol were in the low normal range, but there was no increase in plasma cortisol or urinary 17-hydroxysteroids following stimulation with ACTH. The responses of cortisol, deoxycorticosterone, and corticosterone to ACTH stimulation gradually improved to achieve normal stimulated levels 18 months after stopping medications. Serum testosterone and delta 4-androstenedione were initially increased for level of puberty, while levels of dehydroepiandrosterone were prepubertal. Testosterone and delta 4-androstenedione did not suppress with dexamethasone (2 mg/d for 2 d; 4 mg/d for 2 d), and dehydroepiandrosterone decreased only slightly. However, administration of norethindrone (Norlutin) (10 mg orally, three times a day for 3 d) resulted in suppression while human chorionic gonadotrophin (hCG; 5000 U i.m. daily for 3 d) produced stimulation of testosterone, delta 4-androstenedione and dehydroepiandrosterone. Thus the androgens were felt be predominantly of ovarian origin. Dehydroepiandrosterone rose to low normal levels by 18 months after discontinuation of hydrocortisone. We thus demonstrate for the first time that both the adrenal glomerulosa and fasciculata have the capacity to recover normal function following treatment with o,p'-DDD. Further, we suggest that early exposure to excess adrenal androgens may result in mild alteration of gonadal function.