Effect of cortisol treatment on hormonal relationships in congenital adrenal hyperplasia

The temporal relationship between administration of cortisol and serum 17alpha-hydroxyprogesterone was investigated in five patients aged 9-19 years with congenital adrenal hyperplasia due to 21-hydroxylase deficiency. There was marked variability in the 17alpha-hydroxyprogesterone response (determined hourly for 24 h) of individual patients to administration of cortisol. Mean concentration was less than 0.030 micronmol/l in one patient but 0.519 micronmol/l in another. Levels were higher in all patients while off treatment, and were greatest in those with salt-losing adrenal hyperplasia. Growth hormone secretion was not suppressed by treatment with cortisol. Withdrawal of cortisol for 3 days resulted in a significant decrease in the mean serum FSH/LH ratio and a rise in serum testosterone in all subjects. Episodic release of gonadotrophins persisted in the adolescent patients.