The metyrapone test in pituitary dwarfs-determination of serum Cortisol and 11-deoxycortisol by high performance liquid chromatography (HPLC)

Children with growth hormone deficiency may also have deficiencies of other pituitary hormones. The pituitary reserve of corticotropin (ACTH) may be evaluated in the metyrapone test. The purpose of the present study was to investigate the pituitary adrenal axis in a two day oral metyrapone test with simultaneous measurement of serum cortisol (F) and 11 deoxycortisol (S) level by HPLC in thirty children aged 5 - 16, with diagnosed growth hormone deficiency. Blood samples were collected before and after metyrapone administration. After metyrapone serum S levels over 8,7 μg/dl and F below 7 μg/dl excluded ACTH deficiency in 19 patients. Nine patients demostrated absent or subnormal ACTH reserve - fail to rise of S with F below 7 μg/dl. Two patients had no changes in serum levels of both S and F during the test, probably due to inadequate effect of metyrapone. To ensure that sufficient inhibition of cortisol production has occured, it is important to measure F in the serum as well as S. HPLC is therefore a very useful method of corticosteroid analysis especially for metyrapone test.