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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A new class of 15-azasteroid analogues has been synthesized and tested for antimicrobial activity. The compounds 1, 10, 11, 11a-tetrahydro-7-methoxy-11a-methyl-2H-naphth (1,2-g) indol (methoxyimine) and 1,10,11,11a-tetrahydro-11a-methyl-2H-naphth (1,2-g) indol-7-ol (hydroxyimine) inhibit the growth of Bacillus subtillis and Escherichia coli at concentrations as low as 10-5 M. Addition of either compound to the growth medium casued a rapid inhibition in the transport of radioactive glucose, uracil and several amino acids. The inhibition of growth and substrate transport was reversed following removl of the steroid from the medium. The evidence is consistent with a site of steroid action at the cell periphery. Combining the methoxyimine with polyor circulin at subinhibitory concentrations produced greatly enhanced antimicrobial activity against Pseudomonas fluorescens. Similar action was observed against B. subtilis when the azasteroid was combined with vancomycin or chloramphenicol. The inhibitory action of other antibiotics such as penicillin or erythromycin was not affected by addition of the test compound. The results suggest formation of a molecular complex between the azasteroid and antibiotic which is responsible for the enhanced biological activity.
Steroids 1976 Apr
PMID:Antibacterial activity of 15-azasteroids alone and in combination with antibiotics. 17 69

In the present paper we report on an improved procedure for the preparation of free uterine cells which avoids the use of trypsin and employs very low concentration of collagenase. The cells released mechanically from the digested tissue are constantly removed from the enzyme containing medium, thus minimizing exposure to collagenase. 60%-70% of the cells which make up the intact uterus are obtained as free cells and 95% of these cells are viable for at least 15 hours at 37 degrees. Metabolic integrity was assessed by measuring the cell's ability to oxidize glucose and synthesize proteins over extended periods of time. The membrane leucine carrier protein and the membrane Na+/K+ ATPase were found to be fully functional. Electron microscopic analysis of the cells confirmed their structural integrity. Data are presented illustrating that with this system the estrogen binding protein is stable at physiological temperatures. The cells contain approximately 30,000 specific estrogen binding sites, with an apparent KA of 5--6 x 10(9) M-1. At 37 degrees 80% of the hormone receptor complexes were in the nuclear fraction, 20% in the cytoplasm. The similarity of the estrogen receptor binding parameters with those measured in the intact tissue after in vivo hormone adminsistration, together with the cells' structural and metabolic integrity make this procedure for the preparation of uterine cell suspensions in high yields particularly suitable for studies in which minimal cell injury is an essential prerequisite.
Steroids 1979 Apr
PMID:An improved procedure for the preparation of rat uterine cell suspensions. 22 Jul 54

Mechanisms whereby glucocorticoids might inhibit growth are reviewed from the perspective of glucocorticoid effects on cell metabolism and growth. Although glucocorticoids given to patients decrease levels of growth hormone and possible somatomedins, the effect of glucocorticoids on growth is not reversed when growth hormone is given. Glucocorticoids inhibit cell growth in culture. Cell inhibition correlates with binding of steroids to the glucocorticoid receptors. Some tissues are very sensitive; others are insensitive. In cell culture, changes in sensitivity can be associated with changes in binding, but this is not always the case in tissues of the animal. The mechanisms of inhibition of cell growth are not known. It could be due to steroid-induced synthesis of inhibitory proteins or to blocking by receptor-steroid complexes of the synthesis of RNA. Steroids may affect uptake of substrates, e.g., glucose or amino acids, which in turn affects growth. The inhibitory actions of glucocorticoids on individual tissues may explain why these steroids inhibit growth in the animal. It is not known, however, how the steroid inhibits linear growth in mass or which cell types are most important targets for such effects.
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PMID:Mechanisms of glucocorticoid inhibition of growth. 36 26

Glucose- 6phosphate dehydrogenase (G-6PDH) stimulation by estradiol- 17beta has been studied in oviduct and liver of Bufa arenarum. OviducalG-6PDH has been found to be stimulated by a single dose of estradiol- 17beta (100 mug/100 g body weight), the stimulation being dependent on season. Hepatic G-6PDH of females is susceptible to hormonal stimulation, without seasonal variation, while in males the enzymatic activity is not modified under the same conditions. The stimulating effect of estrogen on oviducal and hepatic G- 6PDH was inhibited by Actynomicin D. The susceptibility of G- 6PDH to estrogenic action would assure NADPH production, indispensable for the biosynthesis of lipids which are required for cell growth and for hepatic vitellogenesis.
Steroids 1977 Feb
PMID:Effect of estrogens on glucose phosphate dehydrogenase activity of liver and oviduct in the amphibian Bufo arenarum. 40 19

Matabolic fate of a new antiandrogen, 16 beta-ethyl-17 beta-hydroxy-4-estren-3-one (TSAA-291), was studied in rats. 14C-TSAA-291 intramuscularly injected as an aqueous suspension was absorbed gradually to give an increase in the plasma level which attained a plateau at 0.5 h, persisted till 8 h and then declined with an approx. half-life of 3.6 days. The drug was widely distributed in tissues, with the concns. almost equal to or higher than that in the plasma. The 14C-drug was eliminated mostly as metabolites within 10 days after dosing with higher activities found in the feces than in urine. Biliary 14C effectively underwent enterohepatic cycling. Biliary metabolites of TSAA-291 were characterized by the combined use of deuterium labeling and GLC-MS analysis. The metabolites identified were as follows: the parent drug, monohydroxy TSAA-291 having the additional hydroxy function in the steroid skeleton, 17 beta-hydroxy-16 beta-(1 xi-hydroxyethyl)-4-estren-3-one, 16 beta-ethyl-17 beta-hydroxy-5 beta-estran-3-one, 16 beta-ethyl-17 beta-hydroxy-5 alpha-estran-3-one, 16 beta-ethyl-5 beta-estrane-3 alpha, 17 beta-diol, 16 beta-ethyl-5 alpha-estrane-3 alpha, 17 beta-diol, 16 beta-ethyl-3 alpha-hydroxy-5 beta-estran-17-one and 16 beta-ethyl-3 alpha-hydroxy-5 alpha-estran-17-one. Monoketodihydroxy and/or trihydroxy metabolites were also detected in the bile.
Steroids 1979 Jan
PMID:Disposition and metabolism of 16 beta-ethyl-17 beta-hydroxy-4-estern-3-one (TSAA-291), a new antiandrogen, in rats. 45 62

The metabolism of a C26 bile alcohol (I, 24-nor-5beta-cho-lestane-3alpha, 7alpha,25-triol) was studied in the isolated perfused rabbit liver. The new bile alcohol and bile acid metabolites secreted into the bile were isolated and identified by a combination of TLC, GLC and GLC-MS. The following bile alcohols were found: II, 24-nor-5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol, III, 24-nor-5beta-cholestane-3alpha,7alpha,12alpha,25,26-pentol; IV, 24-nor-5beta-cholest-23-ene-3alpha,7alpha,12alpha-triol; and V, 24-nor-5beta-cholest-23-ene-3alpha,7alpha-diol. In the bile acid fraction, 24-nor-cholic acid and 3alpha,7alpha,12alpha-trihydroxy-24-nor-5beta-cholest-23-en-26-oic acid were present. The perfused nor-triol was not resistant to 12alpha-hydroxylation.
Steroids 1977 Oct
PMID:Metabolism of bile alcohols in the perfused rabbit liver - C26 bile alcohols. 60 60

A gas-liquid chromatographic method has been devised for the routine estimation of the hecogenin [3beta-hydroxy-(25R)-5beta-spirostan-12-one] and tigogenin [ (25R)-5beta-spirostan-3beta-ol] contents of Agave sisalana leaf and juice samples and of the crude sapogenin concentrates known as "coffee grounds". Because of partial degradation of the sapogenins in the GLC system it was found necessary to acetylate the compounds prior to their estimation. In East African samples the tigogenin proportion of the total sapogenin content is usually about 10%. At this level, the 95% inverse tolerance limits on predicted tigogenin weights are approximately +/- 7%.
Steroids 1978 May
PMID:A quantitative gas-liquid chromatographic method for the estimation of hecogenin and tigogenin in the leaves, juice and sapogenin concentrates of Agave sisalana. 67 38

Marked variations in the 3beta-hydroxysterol content of hamster spermatozoa were observed as they progress through the epididymis. Cholesterol is the major sterol of caputal spermatozoa while the concentration of precursors of cholesterol was higher than that of cholesterol in caudal spermatozoa. One of these precursors has been identified as desmosterol. A second sterol has now been identified as 5alpha-cholestra-7,24-dien-3beta-ol by GLC-MS and by NMR. Its concentration is approximately 3-fold higher than that of cholesterol. This 3beta-hydroxysterol is also found in epididymal tissue.
Steroids 1978 Dec
PMID:5alpha-Cholesta-7,24-dien-3beta-ol as a major sterol of the male hamster reproductive tract. 73 99

The action of estrogens on glucose metabolism has been proven more than 30 years ago. Estroprogestational agents do not modify sensibly glucose metabolism in normal women, but they do have a serious diabetogenic effect on women with hereditary antecedents of diabetes. These women can use oral contraception only under strict surveillance. Estroprogestinic agents should never be administered to women with latent diabetes; they can be administered to women with diabetes only if glycemia and vascular conditions are constantly checked. It is possible that minipills can cause fewer glucose metabolism complications. Steroids used as male contraceptives have no influence on lipid and glucose metabolism. Natural estrogens administered during and after menopause can improve the glucose tolerance in diabetic patients. It is still not clear what mechanism governs the diabetogenic effects of estroprogestinic agents. The article contains a detailed review of the literature on the subject, and a very useful table listing all combined oral contraceptives available in France.
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PMID:[Diabetes and estro-progestins]. 88 24

The neutral urinary excretion products of 17beta-hydroxy-2alpha, 3alpha-cyclopropano-5alpha-androstane from the rabbit, dosed orally, were investigated. Column chromatography yielded five crystalline metabolites which were identified by GLC and spectroscopic measurements. Three of these substances were hydroxylated in the 4alpha-position and one in the 6alpha-position with the cyclopropane ring intact. The fifth substance, 17beta-hydroxy-3beta-methyl-5alpha-androstan-2-one, can be derived from initial hydroxylation of the cyclopropane ring at C-2 followed by ring opening. The dosed substance and triol material was shown to be present by GLC and m.s. measurements. GLC determinations show that hydroxylation has occurred at C-4-C-6-C-2.
Steroids 1976 May
PMID:Metabolism of 17 beta-hydroxy-2alpha, 3alpha-cyclopropano-5alpha-androstane in the rabbit. 94 Nov 78


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