[Isolation and identification of two new epimer from the mother liquid of megestrol acetate].

AIM: To study the impurity in the drug megestrol acetate. METHODS: Chromatography methods were used to separate the chemical constituents. Their structures were determined by NMR and MS spectral analysis. RESULTS: Two new epimers were isolated from the mother liquid of the drug megestrol acetate. CONCLUSION: These new epimers were identified as 17alpha-acetoxy-2beta,6alpha-dimethylprega-4-ene-3,20-dione (1) and 17alpha-acetoxy-2alpha,6alpha-dimethylprega-4-ene-3,20-dione (2).

Pregnane-type steroids from the inedible mushroom Thelephora terrestris.

Chromatographic fractionation of the methanol extract of fruiting bodies of the inedible Japanese mushroom Thelephora terrestris (Thelephoraceae) has led to the isolation and characterization of two unusual new pregnane-type steroids, 2beta,3alpha-dihydroxypregna-4,7,16-trien-12,20-dione (2) and 1alpha,2beta,3alpha-trihydroxypregna-4,7,16-trien-12,20-dione (3) named terresterones A and B (2, 3), as well as the previously known compound stizophyllin, now assigned as 2beta,3alpha,12beta-trihydroxypregna-4,7,16-trien-20-one (1). Elucidation of their structures and the revision of the stereochemical assignment of stizophyllin were achieved by means of extensive 1D and 2D NMR, UV, CD, IR, MS and molecular modeling experiments. This paper presents the first report on the isolation of true pregnane-type steroids from the Fungi kingdom.

Defensive steroids from a carrion beetle (Silpha americana).

The defensive anal effluent discharged by Silpha americana in response to disturbance contains a mixture of steroids stemming from a glandular annex of the rectum. The compounds have been characterized as 15 beta-hydroxyprogesterone (1, principal component), 5 beta-pregnan-15 beta-ol-3,20-dione (2), 5 beta-pregnan-3 alpha, 15 beta-diol-20-one (3), 5 beta-pregnan-7 beta, 15 beta-diol-3,20-dione (4), 5 beta-pregnan-3 alpha, 7 beta, 15 beta-triol-20-one (5), 5 beta-pregnan-16 alpha-ol-3,20-dione (6), and 5 beta-pregnan-3 alpha, 16 alpha-diol-20-one (7), none previously found in insects. Bioassays with jumping spiders showed compounds 1 and 6 to be feeding deterrents at the 1 microgram level.

5 alpha-Reductase activity in human placenta.

The concentration of 5 alpha-pregnane-3,20-dione in peripheral blood of pregnant women is higher than that found in blood obtained from nonpregnant women throughout the luteal phase of the ovulatory cycle. The in vitro synthesis of 5 alpha-reduced pregnanes from [3H]progesterone by placental tissue was investigated using tissue minces and homogenates in the presence of added nicotinamide-adenine dinucleotide phosphate. The metabolites, [3H]5 alpha-pregnane-3,20-dione and [3H]3 beta-hydroxy-5 alpha-pregnan-20-one, were isolated and characterized employing a combination of chromatographic techniques, derivative formation, and crystallization with authentic [14C]5 alpha-pregnane-3,20-dione and [14C]3 beta-hydroxy-5 alpha-pregnan-20-one to constant 3H:14C ratios. In short-term incubations with placenta homogenates, the apparent pH optimum for the synthesis of 5 alpha-pregnane-3,20-dione was 8.8. There was no evidence for the formation of 5 beta-reduced pregnanes from [3H]progesterone by placental tissue. The in vitro metabolism of [3H]progesterone by minces of five term placentas, during 1 hour incubations at pH 7.4, was studied. The rate of formation of 5 alpha-pregnane-3,20-dione varied from 109 to 197 pmoles/gm placental tissue/hr.

Temporal changes in activities of enzymes reducing ring-A of progesterone in the fetus and placenta of the rat.

The development of delta4-5alpha-reductase and 3alpha- and 3beta-hydroxysteroid dehydrogenases in rat fetuses and placentas was detected by the production of specific metabolites during in vitro incubation with progesterone. The metabolites, 5alpha-pregnane-3,20-dione, 3alpha-hydroxy-5alpha-pregnan-20-one, and 3beta-hydroxy-5alpha-pregnan-20-one, were identified by isolation and purification by thin-layer chromatography and reverse isotope dilution, followed by recrystallization of the free compound and a derivative. The delta4-5alpha-reductase and the 3beta-hydroxysteroid dehydrogenase are associated with the particulate fraction. However, 3alpha-hydroxysteroid dehydrogenase is a soluble enzyme present in the supernatant fraction of homogenized placentas and fetuses. The activities of these enzymes were greater in the placenta than in the fetus. As pregnancy progresses, the activities increase in the fetus, but diminish in the placenta. Although the placenta secretes only marginal amounts of progesterone, it has a notable capacity to metabolize progesterone to 5alpha-reduced metabolites. The fetus has the ability to utilize progesterone as early as day 13, and its potential to convert progesterone into ring-A reduced products increases during gestation.

Isolation and characterization of 5alpha-pregnane-3,20-dione and progesterone in pepipheral blood of pregnant women. measurement throughout pregnancy.

5alpha-Pregnane-3,20-dione and progesterone were isolated from a pregnancy plasma pool and were identified by using a combination of chromatographic techniques and mass spectrometry. Antibodies to progesterone were obtained in rabbits by immunization with progesterone-1alpha-carboxyethyl-thioether-thyroglobulin. The raised antibodies were of high affinity and one of them cross-reacted (137%) with 5alpha-pregnane-3,20-dione. This property was used to develop radioimmunoassays for measuring circulating levels of both progesterone and 5alpha-pregnane-3,20-dione in pregnancy plasma. The levels of both progesterone and 5alpha-pregnane-3,20-dione increase throughout pregnancy, but a highly significant increase is observed only after the 32nd week of gestation.