Max L. Sweat

The synthesis and metabolism of progesterone in the human and bovine ovary

Abstract 1. 1. The biosynthesis of progesterone from [1-14C]acetate has been demonstrated. 2. 2. By means of in vitro incubations of [4-14C]progesterone and [4-14C]androstenedione in human ovarian tissue, a continuous spectrum of intermediate compounds leading to the synthesis of estrogens has been demonstrated. Presumption evidence has been obtained for the following products: 6β-hydroxyprogesterone, pregnanedione, allopregnanedione, 20a-hdyroxypregnene-3-one, 20β-hydoxypregnene-3-one, 17-hydroxyprogesterone, 17α-20ζ-dihydroxypregnene-3-one, 20ζ-hydroxypregnane-3-one, androstenedione, estrone, and estradiol-17β.

Studies of the oxidation state of partially purified adrenal cortex mitochondrial cytochrome P-450 and difference spectra induced by deoxycorticosterone and metopirone.

Abstract Cytochrome P-450 prepared from extracts of adrenal gland cortex mitochondrial acetone powder exists in the oxidized state as it will not complex with carbon monoxide. Both deoxycorticosterone and Metopirone will induce spectra in the preparation in the absence of oxygen and reductase components. Metopirone displaces the deoxycorticosterone-induced difference spectrum of the cytochrome P-450 preparation, but excess deoxycorticosterone does not influence the Metopirone-induced spectrum suggesting different complexing mechanisms for the two compounds. The observations are consistent with the concept that the steroid-induced spectrum is the result of a direct complexing with ferric cytochrome P-450, or a closely associated companion pigment dependent upon the ferric state of cytochrome P-450. Current observations indicate experimentally separable reaction steps in the overall system of 11β-hydroxylation.

Is mevalonic acid a precursor of the corticosteroids

Abstract Bovine adrenal tissue preparations (whole homogenates or a combination of microsomal and supernatant fractions) readily convert acetate-1-C 14 to corticosteroids, 14 of which have been isolated and identified. In parallel experiments with aliquots of the same adrenal tissue preparations, mevalonate-2-C 14 was not found to be incorporated into any of these corticosteroids.

The role of phosphopyridinenucleotides in the metabolism of cortisol by peripheral tissue

Abstract 1. 1. Cortisol incubated with muscle tissue is metabolized to cortisone, dihydrocortisol, corticosterone, 11-β-hydroxyandrostenedione, Reichsteins substances E and U, dihydrocortisone, Kendalls Compound A and adrenosterone. 2. 2. The reaction, cortisol → cortisone is TPN specific. DPN appears to inhibit the reaction. No evidence was obtained for the presence of a transhydrogenase in muscle tissue. Reduction at C-4, 5, and C-20 appears to be TPNH specific. 3. 3. Studies of the metabolism of cortisone in muscle and liver indicate that the major product in liver is cortisol. The major product in muscle is Reichsteins substance U.

Comparative metabolism of progesterone in proliferative human endometrium and myometrium

Abstract In contrast to hepatic metabolism of progesterone, which gives rise to 5β-pregnane derivatives, both endometrium and myometrium are unique in that they reduce the Δ 4 bond of progesterone to form predominantly allo (5α) pregnane products. Differences in progesterone metabolism also exist between endometrium and myometrium. These metabolic differences may relate to the different hormonal effects of progesterone (secretory activity in the endometrium; inhibition of muscle contraction in the myometrium). The major product in endometrium is an unknown dihydroxy compound. 4-Pregnen-20α-ol-3-one is the major product of myometrium. Six additional products have been identified in endometrium; 3 in myometrium. The metabolic pathways of progesterone observed are evaluated in light of possible progesterone hormonal mechanisms.

Preparation of a soluble progesterone 17α-hydroxylating system

Abstract Examination of differentially centrifuged homogenates of bovine adrenocortical tissue reveals that the steroid 17α-hydroxylating system resides primarily in the particle-free cytoplasm. Preparations are relatively labile. Higher activity is noted in fresh unfrozen glands than from frozen ones. 17-Hydroxylation is inhibited less in higher pH media and in media containing p -chloromercuribenzoate than is 21-hydroxylation.

Comparison of cortisol metabolism by two variants of cultured fibroblasts

Abstract Fibroblasts, strain U12-79, convert 4-pregnene-11β,17α,21-triol-3,20-dione (cortisol) to 4-pregnene-11β,17α, 20β, 21-tetrol-3-one, 4-pregnene-17α,21-diol-3,11–20-trione, 4-pregnene-11β,21-diol-3,20-dione, 4-androstene-11β-ol-3,17-dione, and an unidentified steroid. Tbc same pattern of cortisol metabolism was observed in a variant strain of U12-79, designated U12-35, which is 250 times as resistant to the growth inhibitory action of cortisol as the parent U12-79 line. Cortisol, however, is metabolized at least twice as fast by the steroid-resistant cells. These data are discussed with regard to mechanism of resistance and are compared with the results obtained in other studies of steroid-resistant cells.

Steroid 17α-hydroxylation in the rat adrenal gland

Abstract A 17α-hydroxylating system has been demonstrated conclusively for the first time in normal rat adrenal tissue. The system is precipitated from extracts of adrenal tissue at 40% saturation of ammonium sulfate. When this fraction is incubated with protein components precipitated at 80% saturation of ammonium sulfate, only 11β-hydroxylation occurs. It is concluded that the normal rat adrenal gland has the capacity to 17α-hydroxylate progesterone, but that this reaction as studied in vitro is inhibited in the presence of the 11β-hydroxylating system. To what extent this inhibition occurs in situ is not known.

Low magnitude transformation of estradiol to estrone in human endometrium

Abstract 1. 1. The human endometrium estradiol dehydrogenase has been shown to function at magnitudes significantly lower than those in which estradiol binding has been examined. Quantities as low as 0.0075 fmole have been shown to be transformed to 0.006 fmole of estione in 1 min by 1 mg of tissue. 2. 2. In sonicated preparations, transformation of estradiol to estrone is enhanced by NAD + and NADP + . NADPH does not influence the reverse reaction. 3. 3. The dehydrogenase appears to be cold sensitive, conforming to the observations of Jarabak et al. (Jarabak, J., Seeds, A. S., Jr and Talahay, P., (1966) Biochemistry 5, 1269) with the placental estrogen dehydrogenase.

Conversion of pregnenolone to progesterone by human endometrium in vitro

Abstract Pregnenolone-4-14C was incubated in vitro with human endometrium. One of the products isolated by reverse isotope dilution and paper chromatographic techniques was shown to be progesterone. It is concluded from this observation that the endometrium possesses a functional 3β-ol-dehydrogenase-isomerase enzymic system.