BIOSYNTHESIS TRANSPORT AND METABOLISM OF ADRENOCORTICAL HORMONES ::;
All the hormones of adrenal cortex have a common basic structure cyclo pentanoper hydrophenan threne or steroid ring Cholesterol is the major precursor of all steroid hormones It is formed from acetate Cholesterol under the influence of ACTH is converted into pregnenolone after hydroxylation and side chain clevage Pregnenolone after dehydrogenation is converted into progesterone It may also be converted into 17 hydroxypregnenolone by the enzyme 17-<-hydroxylase
From progesterone 11-deoxycorticosterone and corticosterone are formed Corticosterone may be converted into aldosterone In another pathway 17-hydroxpregnenolone is converted into 17-hydroxyprogesterone and cortisol (a glucocorticoid ) From 17-hydroxypregnenolone androgens and estrogen the sex steroids are formed
Cortisol is the main glucocorticoid in human blood it is transported after being bound to a specific <-globulin transcortin Aldosterone is also present in plasma in very small quantity it is mainly bound to albumin Estrogen and progesterone are also bound to albumin Steroids are metabolised in liver and excreted in urine
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