Dexamethasone suppressibility of plasma pregnenolone (3 beta-hydroxy-5-pregnen-20-one) in normal men.
In order to examine the dexamethasone suppressibility of plasma pregnenolone, 9 a.m. and overnight suppression tests were performed in normal adult subjects and plasma pregnenolone levels were radioimmunoassayed. The results were as follows: 1) In the 9 a.m. test, plasma pregnenolone was suppressed to the lowest level at the time between 30 min and 2 hr after dexamethasone; 2) there was no significant difference in dexamethasone suppressibility of plasma pregnenolone between the 9 a.m. test and overnight test; 3) there was no significant difference from each other among the plasma pregnenolone levels after dexamethasone administration (0.5 mg to 3 mg) in both tests; 4) after dexamethasone administration, plasma pregnenolone was not suppressed below 40% of the basal level in both tests; 5) discussions were made about the results, comparing with those of the suppressibility of cortisol which were previously reported from this laboratory.
D000328:Adult; D003864:Depression, Chemical; D003907:Dexamethasone / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D011284:Pregnenolone / Q000097:blood*; D011863:Radioimmunoassay
D011284:Pregnenolone; D003907:Dexamethasone