Deoxycorticosterone hydroxylation

If the defect is in 11-hydroxylation, large amounts of deoxycorticosterone are produced, and because this steroid has mineralocorticoid activity, hypertension with or without hypokalemic alkalosis ensues. When 17-hydroxylation is defective in the adrenals and gonads, hypogonadism is also present. However, increased amounts of 11-deoxycorticosterone are formed, and the signs and symptoms associated with mineralocorticoid excess—such as hypertension and hypokalemia—are also observed. 

Aldosterone production is initiated by 21-hydroxylation of pregnenolone in the adrenal glomerulosa, where there is no 17-hydroxylase activity. The product of hydroxylation of pregnenolone by P450c21 is 21-hydroxy-progesterone, also known as deoxycorticosterone (DOC). The quantity of aldosterone produced by the adrenal is only 1% of that of cortisol for this reason, not all patients with classic P450c21 deficiency manifest with salt wasting. 

The pattern of inhibition of 17a-hydroxylase exhibited by metyrapone lends further support to the hypothesis that cytochrome P450 is involved in the enzyme system319 whilst the effect of administration of spironolactone on the cytochrome P450 content and 17a-hydroxylase activity in adrenal tissue has shown that decreases in both of these factors occur only in animals that produce predominantly cortisol rather than corticosterone.320 18-Hydroxylation of deoxycorticosterone has been demonstrated in rat and bovine mitochondrial preparations and in reconstituted systems obtained from these fractions.321 In all cases, 18-hydroxylation was accompanied by 11/8-hydroxylation, and the study indicated that very similar types of cytochrome P450 were involved in both hydroxylation systems. 

The ll-/3-hydroxylase found in the adrenal cortex catalyzes the hydroxylation of 11-deoxycorticosterone to corticosterone. The enzyme requires NAD as a cofactor and contains heme as the prosthetic group. 

The substrate, 11-deoxycorticosterone, was separated from the two reaction products, corticosterone (11-jS-hydroxylation) and 18-hydroxyl-ll-deoxycorticosterone (18-hydroxylation), on reversed-phase HPLC (MicroPak... 

Microbial 15x-hydroxylation of steroids was discovered with Gibherella baccatu on deoxycorticosterone (l)139, then noted with Colletotrichum antirrhini on progesterone141. 

In addition to the usual suffixes and prefixes just discussed, a few special prefixes are usually used for the semi-trivial names of the compounds. Thus the prefix dehydro- is used to indicate the loss of two hydrogen atoms from adjacent carbon atoms with the formation of a double bond (e.g, dehydroepiandrosterone). The prefix dihydro- or tetrahydro- indicates the addition of two or four hydrogen atoms to the molecule, respectively, as in dihydrocortisol and tetrahydrocortisol. The replacement of a hydroxyl group by hydrogen (COH CH) is denoted by the prefix deoxy- (or desoxy- [e.g., 11-deoxycorticosterone]). 

Aldosterone is a by-product of the 21-hydroxylation of pregnenolone to form deoxycorticosterone. The oxidation of 18-hydroxycorticosterone to aldosterone is a unique feature of the zona glomerulosa, explaining why aldosterone is not affected during disease processes limited to the fasciculata and/or reticularis. 

The separation of endogenous 17- or 18-hydroxylated corticosteroids of the 21-hydroxylated 4-pregnen series was obtained by capillary electrophoresis of their charged borate chelate complexes (323). Aldosterone, 18-hydroxycorti-costerone, 18-hydroxy-deoxycorticosterone, cortisone, cortisol and 11-deoxycor-tisol are separated and resolved with 400 mM borate buffer at pH 9.0. The corticosteroid/borate chelation complex as indicated by CE data correlated well with 11 B-NMR. The separation of corticosteroids and benzothiazin analogs were studied by MEKC and a comparison with CZE was made (324). Bile salts, which have a similar carbon skeleton to the corticosteroids, were used for the separation of these steroids. A short analysis time, 15 min, and a high number of theoretical plates (150,000-350,000) were obtained. Sodium cholate was found to be very effective. The MEKC method was applied to the determination of the drug substance in tablets and cream formulations. An internal standard method was used for quantitation. The purity of the drug substance was also determined. 

Progesterone is synthesized from either cholesterol or alkylated plant sterols by a pathway similar to that in animals. Hydroxylation at C-20 and C-22 is a prerequisite for removal of the C-6 residue of the side chain (A, B, C, Fig. 16). The product pregnenolone is then reduced to progesterone (D, Fig. 16). Traces of oestrone, testosterone, deoxycorticosterone and closely related compounds have been found in plants but nothing is known of their biosynthesis. 

The glucocorticoids mainly influence carbohydrate metabolism and, to a certain extent, protein and lipid metabolism (see Table 14 and Figure 55). The main glucocorticoid is cortisol, with a daily secretion of 15 mg. Cortisol is synthesized through the 11-beta-hydroxylation of 11-deoxy-cortisol. Besides cortisol, the adrenal gland also synthesizes and releases a small amount of corticosterone, whose synthesis from 11-deoxycorticosterone is catalyzed by 11-beta-hydroxylase. A deficiency of 11-beta-hydroxylase causes ... 

Similar strategies have been used to develop inhibitors that target the C-18 hydroxylation involved in the biosynthesis of aldosterone . Thus, aldosterone analogs with C-18 iodomethyl, chloromethyl, allyl, propargyl, vinyl, and methyl-thiomethyl functionalities have been synthesized and some have been found to irreversibly inactivate the enzyme. An active site-directed 18-acetylenic deoxycorticosterone [21 -hydroxy-13(-2-)propy-... 

P450 11B2 catalyzes the three-step conversion of 11-deoxycorticosterone to aldosterone, with 1 ip-hydroxylation, 18-hydroxylation, and 2-electron oxidation of the 18-carbinol (Figures 10.13 and 10.14). No other substrates are known. Information about the processivity of the human enzyme (i.e., extent of release of intermediate products) is not available at this time. 

In the pathway of cortisol synthesis, the 17-hydroxylation of progesterone yields 17-a-hydroxyprogesterone, which, along with progesterone, is transported to the smooth endoplasmic reticulum. There the membrane-bound P450c2i (21-a-hydrox-ylase) enzyme catalyzes the hydroxylation of C21 of 17-a-hydroxyprogesterone to form 11-deoxycortisol (and of progesterone to form deoxycorticosterone [DOC], a precursor of the mineralocorticoid, aldosterone see Fig. 34.23). 

Chlorthion, malathion and parathion inhibit the hydroxylation of testosterone by liver microsomes in vitro, and administration of chlorthion to rats in vivo was found to inhibit the hepatic metabolism of oestradiol-17/ , progesterone, deoxycorticosterone and testosterone [126],... 

While Merck, beginning in 1949, and Sobering, in 1951, manufactured cortisone from deoxycholic acid, Peterson and Murray, biochemist and microbiolc st, respectively, with the Upjohn Company, chose to attack the problem of the introduction of 11-oxygen by the potentially more direct, microbiological method. They have said (P-723) that they were stimulated to enter this fi d by the successes of the Mamoli school. They were also encouraged, early in their work, by the report of Hechter and collaborators that perfusion of deoxycorticosterone through isolated adrenal glands resulted in the formation of corticosterone by enzymatic 11/3-hydroxylation. 

If a 17o -20-ketopregnane (e.g., 17a-deoxycorticosterone) is subjected to the action of a 17a-hydroxylating organism (e.g., Trickothecium roseum) the isolation of either a 17a-hydroxy-20-ketopr nene (e.g.. Compound S) or a 17/3-20 -ketopregnane (e.g., deoxycorticosterone) would give important evidence for the enolization hypothesis. Since the formation of the former would be an apparent violation of the rule for... 

Q -Hydroxylation. The earliest example of 14a-hydroxylation was reported by Murray and Peterson (M-601) withHelicostylumpiriforme on Compound S. This transformation is quite common with progesterone, deoxycorticosterone and Compound S. Mucor sp. are among the more effective 14a-hydroxylators (E-204, M-614, M-635, T-980). 

ISa-Hydroxylation. This hydroxylation was discovered by Fried and colleagues with Colletotrichum antirrhini on progesterone (F-285, F-287, F-288) and by Meystre, Vischer, and Wettstein with Gt66ereZZa feaccata on deoxycorticosterone (M-585, U-1043, W-1087). It can be accomplished efficiently with a variety of substrates (B-58, C-139, D-158, G-319, T-980). 

Ap-58 Okada, M., Yamada, A., and Ishidate, J. Pharm. Soc. Japan 816 (1965). 7a-Hydroxylation of dehydroepiandrosterone with Gibberella saubinetti. 15a-Hydroxy-lation of progesterone, deoxycorticosterone, and testosterone with the same organism. 

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