Hypothalamic-pituitary-thyroidal axis dysfunction and cortisol secretion in patients with nonclassical congenital adrenal hyperplasia.

OBJECTIVE

The purpose of this study was to evaluate thyroid function and TSH and cortisol (F) secretion in hyperandrogenemic women with nonclassical congenital adrenal hyperplasia (NC-CAH) due to 21-hydroxylase deficiency (Group A) when compared with women with hyperandrogenemic symptoms (menstrual irregularities, hirsutism, acne, seborrhea and sterility) of other etiologies (Group B).

METHODS

Seventy-two women were subjected to stimulation of the adrenal cortex with i.v. ACTH administration in the early proliferative phase of the menstrual cycle. Basal plasma TSH, T3, T4, and FTI as well as basal and ACTH-stimulated plasma F and 17-hydroxyprogesterone levels were determined.

RESULTS

According to internationally accepted criteria and HLA haplotyping, we diagnosed 28 NC-CAH patients as well as affected heterozygotes of the disease. No significant difference was found in the plasma T3, T4, or FTI or F concentrations between the women of the two groups. On the contrary, plasma TSH levels were significantly lower in patients with 21-hydroxylase deficiency when compared to the women with hyperandrogenemic symptoms of other etiologies.

CONCLUSION

The results of this study support a dysfunction of the hypothalamic-pituitary-thyroidal axis due to altered ACTH secretion patterns.