Regulation of plasma oestrogens in normal adult males. II. Response of oestradiol, oestrone, testosterone and cortisol to dexamethasone and ACTH administration.

The response of plasma oestradiol (Oe-2), oestrone (Oe-1), testosterone (T) and cortisol to dexamethasone and ACTH administration in normal adult males was ascertained. After an oral dose of 1.5 mg dexamethasone Oe-1 decreased from 2. 51 to 1.85 ng/100 ml (74% of the control level, mean of 15 subjects) over night and after continuing the dexamethasone administration for two more days (twice daily 1.5 mg) Oe-1 decreased to 1.30 ng/100 ml (52%). Oe-2 (control level 1.71 ng/100 ml) and T (678 ng/100 ml) did not change over night, but at the end of the test Oe-2 decreased to 84% and T to 91% of the control level. After a single im injection of 2 mg beta 1-24 cortrophin Oe-1 increased 1.9 times (meanof 13 subjects) without further increase during two more days of treatment (twice daily 1 mg), while Oe-2 did not change over night and decreased to 75% of the control level at the end of the test. Under ACTH T decreased to 66% of the control level over night and to 50% at the end of the test indicating a suppression of the testicular hormone secretion. From these results and those reported previously it was concluded that the testicular hormone secretion influences mainly Oe-2 in peripheral plasma, while Oe-1 depends mainly on the adrenal hormone secretion.