血漿中cortisol代謝産物

-ヒトおよび犬における比較分析-

抄録

To investigate cortisol metabolism in humans and dogs, radioactive cortisol was administered intravenously to 14 healthy volunteers and 2 male dogs. Blood was obtained 2.5 hours later and the metabolites in the plasma were separated by high voltage electrophoresis and paper chromatography, identified by reverse isotope dilution and quantified. The results obtained were as follows.
1) In the human plasma, the unconjugated fraction contained 45%, of total plasma radioactivity, the glucuronide fraction 47%, and the sulfate fraction 4%. In the dog plasma, free metabolites accounted for less (<30%), and conjugated metabolites more (>60%) of plasma radioactivity.
2) In the human plasma, cortisol and cortisone were the major free metabolites and tetrahydrocortisol and tetrahydrocortisone constituted the main bulk of glucuronide conjugates. In the dog plasma, on the other hand, cortols and cortolones were the most abundant metabolites in all fractions, and 20-dihydrocortisol and 20-dihydrocortisone were predominant over cortisol and cortisone.
3) In the human plasma, small amounts of 6-hydroxy-metabolites (6-hydroxycortisol, 6-hydroxycortisone and their C-20 reduced metabolites) were found. In the dog plasma, all fractions contained substantial amounts of 6-hydroxy-20-dihydro compounds. The major one was assumed to be 6-hydroxycortol or 6-hydroxycortolone and others were 6-hydroxy-20-dihydrocortisol and 6-hydroxy-20-dihydrocortisone. No 6-hydroxycortisol or 6-hydroxycortisone was detected.
It is suggested that metabolic disposal of cortisol is quantitatively different in the different species ; i. e. more extensive C-20 ketone reduction and 6-hydroxylation occur in the dog.