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1.
The in vitro and in vivo metabolism of 1,2- 3H-progesterone was studied in estrogen-stimulated and control vaginae of ovariectomized mice. Employing two-dimensional thin-layer chromatography, gas-liquid chromatography and metabolite “trapping” techniques, the major and minor pathways for progesterone metabolism were determined in vitro and shown to involve saturation of the Δ4-double bond to yield 5α-pregnane compounds and reduction of the C20 and C3 ketone groups to form 20α- and 3α- and 3β-hydroxy derivatives, respectively. The quantities of 20β-hydroxy metabolites and 5β-epimers that were detected were considered not to be significant. The major metabolites formed by untreated tissues following in vitro incubation in the presence of both high (10?6M) and low (10?8M) progesterone concentrations were 3α-hydroxy-5α-pregnan-20-one and 5α-pregnane-3,20-dione. Although these two derivatives were also found in sizable quantities in estrogen-treated tissues, a marked increase (5-fold) in the rate of C20 ketone reduction at high progesterone concentrations (10?6M) to yield 20α-hydroxy-4-pregnen-3-one was demonstrated. Following intravaginal administration of 3H-progesterone in vivo, only progesterone and 3α-hydroxy-5α-pregnan-20-one were retained in appreciable quantities through 2 hr, suggesting rapid loss of 20α-hydroxy-4-pregnen-3-one and the 5α-pregnanediols from this tissue under in vivo conditions.  相似文献   

2.
A new glutathione S-transferase from human liver has been purified to homogeneity in good yield by use of ion-exchange chromatography on DEAE-cellulose, affinity chromatography on S-hexylglutathione coupled to epoxy-activated Sepharose 6B, and chromatography on hydroxyapatite. This new enzyme, transferase μ, is present in high concentration, but only in some individuals. It has an isoelectric point at about pH 6 to 6.5 and a different substrate specificity than the previously described alkaline transferases α-ε from human liver. Especially noteworthy is the finding of high activity against benzo(α)pyrene-4,5-oxide. Glutathione S-transferase μ has about 20-fold higher activity with this substrate than have the alkaline transferases. The most pronounced difference was found with trans-4-phenyl-3-buten-2-one which was >100-fold better as substrate for transferase μ than for the previously described transferases.  相似文献   

3.
The syntheses of (±) 2α,6β-diethyl-7α-ethynyl-3α-(p-hydroxyphenyl)-trans-bicyclo[4.3.0]nonan-7β-ol (8), (±)2β,6β-diethyl-7α-ethynyl-3β-(p-methoxyphenyl)-trans-bicyclo[4.3.0]nonan-7β-ol (12) and (±) 2α,6β-diethyl-7α-ethynyl-3β-(p-hydroxyphenyl)-trans-bicyclo[4.3.0]nonan-7β-ol (18) and their derivatives, which are essentially B-seco-steroids having cis-anti-trans, cis-syn-trans and trans-anti-trans geometries have been carried out. A study of their antiimplantation activities (AI) and receptor binding affinities (RBA) show that trans-anti-trans compounds are biologically most potent, followed by the corresponding cis-anti-trans and cis-syn-trans compounds. The most potent compound 18 is active at 1 mg/kg in rats. Introduction of 7α-ethynyl group increases their AI activity; however, no significant effect on their RBA is observed.  相似文献   

4.
Cyclic AMP was not detected in whole cells, expended culture medium or culture supernatant fluid of selected strains of Bacteroides fragilis. Adenyl cyclase and c-AMP phosphodiesterase activities were also not detected in cell extracts of B. fragilis. The exogenous addition of dibutyryl-c-AMP or sodium cholate to cultures of B. fragilis growing on lactose did not significantly affect the specific activity of β-galactosidase measured in cell extracts of this organism. No diauxic growth pattern could be demonstrated in a chemically defined medium containing 5 mM glucose + 28 mM lactose.  相似文献   

5.
An invitro perifusion system was used to investigate the effect of progesterone (P4) and 20α-hydroxyprogesterone (20α-OHP) on the release of GnRH from isolated hypothalamic tissue of the adult ovariectomized estradiol-17β primed rat. Pulse delivery of P4 stimulated GnRH release not only from the isolated mediobasal hypothalamus-anterior hypothalamus-preoptic area (MBH-AHPOA) complex but also from the MBH alone. Release of GnRH from the MBH was also increased by 20α-OHP. These results suggest that the invivo increase of circulating P4 or 20α-OHP associated with the initiation of the preovulatory LH surge may play a role in regulating the timing or amplitude of this surge by directly stimulating the release of GnRH from the MBH.  相似文献   

6.
The in vitro reaction of bacteriophage T7-DNA with the radioactive diastereomeric benzo(a)pyrene-diol-epoxides, (±) [3H9, 3H10]-7β,8α-dihydroxy-9α,10β-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene, and (±) [3H9, 3H10]-7β,8α-dihydroxy-9β,19β-epoxy-7,8,9,10-tetrahydrobenzo(1)pyrene, was investigated. Chromatographic analysis of digests of the DNA allowed the distinction of characteristic deoxynucleoside adduct peaks for the two benzo(a)pyrene-diol-epoxides. Our results, together with data from the literature, allow the identification of these adducts as mostly N2-(10-7β,8α,9α-trihydroxy-7,8,9,10-tetrahydrobenzo(a)pyreney1)deoxyguanosine and N2-(10-7β,8α,9β-trihydroxy-7,8,9,10-tetrahydrobenzo(a)pyreney1)deoxyguanosine, respectively. DNA-benzo(a)pyrene adducts with the same chromatographic properties were formed in mouse embryo fibroblasts upon treatment with benzo(a)pyrene.  相似文献   

7.
The activity of cholesterol 7α-hydroxylase in rat liver microsomes was assayed by measuring the mass of 5-cholestene-3β, 7α-diol formed from endogenous cholesterol under standardized incubation conditions. After termination of incubations, a known amount of 5-[24,25,7β-2H3]cholestene-3β,7α-diol was added. A chloroform extract of the incubation mixture was subjected to thin layer chromatography and the fraction containing 5-cholestene-3β,7α-diol was converted into trimethylsilyl ether. The trimethylsilyl ether was subjected to combined gas chromatography-mass spectrometry and the amount of unlabeled 5-cholestene-3β,7α-diol in the mixture was calculated from the ratio between the relative intensitics of the peaks at me 456 (M-90) and me 459 [M-(90 + 3)]. The precision of the method was ±2.2% (SD). The results with this method of assay of cholesterol 7α-hydroxylase were compared with those obtained with a method based on conversion of a trace amount of added [4-14C]cholesterol into 5-cholestene-3β,7α-diol.  相似文献   

8.
α factor is a diffusible substance produced by S. cerevisiae cells of the α mating type which inhibits cell division (1) and the initiation of nuclear DNA synthesis (2) in cells of the a mating type. In this report, it is shown that mitochondrial DNA synthesis continues at a normal rate in a cells for at least 6 hours in the presence of α factor, resulting in a 5-fold increase in the amount of mitochondrial DNA per cell. The continued synthesis of mitochondrial DNA in the absence of nuclear DNA synthesis allows specific labeling of yeast mitochondrial DNA.  相似文献   

9.
(±)-7β,8α-Dihydroxy-9β,10β-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BP 7,8-diol-9,10-epoxide) is a suspected metabolite of benzo[a]pyrene that is highly mutagenic and toxic in several strains of Salmonellatyphimurium and in cultured Chinese hamster V79 cells. BP 7,8-diol-9,10-epoxide was approximately 5, 10 and 40 times more mutagenic than benzo[a]pyrene 4,5-oxide (BP 4,5-oxide) in strains TA 98 and TA 100 of S.typhimurium and in V79 cells, respectively. Both compounds were equally mutagenic to strain TA 1538 and non-mutagenic to strain TA 1535 of S.typhimurium. The diol epoxide was toxic to the four bacterial strains at 0.5–2.0 nmole/plate, whereas BP 4,5-oxide was nontoxic at these concentrations. In V79 cells, the diol epoxide was about 60-fold more cytotoxic than BP 4,5-oxide.  相似文献   

10.
Syn-α-chloroacetophenone oxime has been found to inactivate papain rapidly at pH 7 and 25.0O in a 1:1 stoichiometric fashion as measured by rate assays with p-nitrophenyl N-benzyloxycarbonylglycinate and sulfhydryl group titrations with 5,5′-dithiobis-(2-nitrobenzoic acid). By the use of a 14C label in the halomethyl function a similar stoichiometric reaction with papain could be demonstrated for syn-α-bromoacetophenone oxime despite the rapidity of the competitive nonenzymatic solvolysis of the latter compound under the conditions employed. These results indicate that a new class of reactive modifying agents, α-haloalkyl oximes, can be used for the selective alkylation of catalytically essential functional groups in enzyme active sites.  相似文献   

11.
A compound was isolated from female Phthorimaea operculella (Lepidoptera: Gelechiidae) abdominal tip extracts and identified as trans-4, cis-7-tridecadienyl acetate. The synthetic compound elicits male P. operculella wing fanning and upwind orientation in the laboratory, and is attractive to males in the field. The corresponding alcohol also appeared to be present in the female extracts, but this compound was not found to increase male responses in the laboratory or the field. Another EAG active component was isolated but not identified.  相似文献   

12.
The addition of cholic acid to growing cultures of Eubacterium species V.P.I. 12708 caused a 25 and 46-fold increase in 7α-dehydroxylation activity using cell extracts or whole cell suspensions, respectively. Bile acid conversion rates using either [14C]-cholic acid or [14C]-chenodeoxycholic acid as substrates increased at approximately the same rate when either cholic or chenodeoxycholic acid was added to growing cultures as inducer. The induction of 7α-dehydroxylase activity was highly specific requiring a free C-24-carboxyl group and an unhindered 7α-hydroxy group on the B ring of the steroid nucleus. Unexpectedly, cholic acid also rapidly induced NADH:flavin oxidoreductase activity in growing cultures of this bacterium.  相似文献   

13.
HL-60, a human promyelocytic leukemia cell line, is induced to differentiate by retinoic acid to mature granulocytes. We have now found that after the addition of 1 μM retinoic acid to HL-60 cultures an increase in NAD+-glycohydrolase (NADase) activity is detected by 6 hr and after a 33-fold increase in activity reaches a plateau by 24 hr. Cycloheximide inhibits completely the retinoic acid-induced increase in NADase activity indicating that enzyme induction requires protein synthesis de, novo. An increase of NADase activity was found not only in HL-60 cells but also in two human monoblast cell lines (U-937 and THP-1) and fresh cells in primary culture from two patients with acute promyelocytic leukemia. An increase in synthesis de, novo of NADase does not appear to be obligatory for differentiation of HL-60 because there was no increase of NADase activity in HL-60 cells induced to differentiate with either dimethylsulfoxide, hypoxanthine, butyrate, or 1, 25-dihydroxycholecalciferol and there were marked increases in NADase activity at concentrations of retinoic acid having little or no effect on differentiation.  相似文献   

14.
The ability of various prostaglandins (PGs) to affect the in vitro anamnestic immune response of keyhole limpet hemocyanin (KLH)-primed rabbit popliteal lymph node cells was investigated. Of the four PGs studied (PGA1, PGE2 and PGF), PGE1 was found to have a stimulatory effect, whereas PGA1, PGE2 and PGF were ineffective in stimulating or inhibiting the in vitro anamnestic response. Under the conditions studied, a 3.5-fold increase in antibody production was obtained in PGE1-treated, KLH-stimulated cultures. Maximum enhancement was obtained when 0.2 μg of PGE1 were added at the time of culture initiation and were allowed to remain in contact with the lymph node cells for 24 hours.  相似文献   

15.
The epididymis of adult rats metabolize 3H-testosterone by experiments in vivo. Thirty minutes after the injection of 100 μCi 3H-testosterone, some 10 per cent of the total radioactivity of the epididymis was found in the water-soluble fraction, whereas 90 per cent was found in the ether soluble fraction (free steroids). The free steroids were examined further and the following androgenic metabolites identified: testosterone (17β-hydroxy-4-androsten-3-one) 8, 9%, androstendipne (4-androstene-3, 17-dione, 2,7%,5α-A-dione (5α-androstane-3, 17-dione) 6,5%, DHT (17β-hydroxy-5α-androstan-3-one) 47, 2%, 3β-diol (5α-androstane-3β, 17β-diol) 4, 4%, 3α-diol (5α-androstane-3α,17β-diol) 20, 8% and androsterone (3α-hydroxy-5α-androstan-3-one) 3,4%. The relative amount of each metabolite is given in per cent of total radioactivity in the ether soluble fraction.  相似文献   

16.
Injection of a luteinizing hormone-releasing hormone (LHRH) agonist into 55-day-old male rats which had been hypophysectomized 3 days earlier resulted in a 10- to 30-fold increase in the levels of testosterone in serum and testicular interstitial fluid (IF) in the 4h following injection. The levels achieved were within or above the normal range for intact untreated rats of this age. In similar animals, injection of LHRH agonist also enhanced the serum testosterone response to injected hCG at 112h, but not at later times after injection, and by 24h reduced IF levels of testosterone suggested that LHRH agonist had begun to inhibit stimulation by hCG. In vitro, dispersed Leydig cells from untreated hypophysectomized rats showed a 2-fold increase in testosterone responsiveness to LHRH agonist when compared to cells from intact rats, and this change was associated with an 80% increase in the number of Leydig cell LHRH-receptors.  相似文献   

17.
Two synthetic routes to 3-deoxy-1α-hydroxyvitamin D3, an analog of 1α,25-dihydroxyvitamin D3, are described. One involved the six-step conversion of 1α,2α-epoxy-6,6-ethylenedioxy-5α-cholestan-3- one to 1α-acetoxycholest-5-ene, whereas, in the second, the same intermediate was prepared from 1α-hydroxycholesterol. Conversion of the Δ5-sterol to the required 5,7-diene was accomplished most efficiently via 7-keto and 7-tosylhydrazone intermediates. Bioassay of 3-deoxy-1α-hydroxyvitamin D3 in the rat establishes that the analog can fulfill all common vitamin D functions including stimulation of intestinal calcium transport, mobilization of calcium and phosphate from bone, stimulation of growth, and calcification of bone. Direct comparison indicates the compound to have 120 to 150 of the activity of 1α-hydroxyvitamin D3, but it acts with a time course indistinguishable from the latter.  相似文献   

18.
Glycerol (50%, w/w) was found to cause blistering of chick primary myoblast and fibroblast plasma membranes and extensive blistering of 5–6-day-old-myotube plasma membranes in tissue culture. The tips of myoblasts and fibroblasts appeared to be the most sensitive portion of the plasma membrane to the blistering effect of glycerol. The glycerol-induced blistering of myotubes was reduced and delayed by brief EDTA pretreatment.Glycerol treatment (50, 15 and 8% sequentially) of myotubes was used to remove plasma membrane blisters and a plasma membrane-enriched fraction was isolated from these blisters using a modified Dextran T500-polyethylene-glycol 6000 aqueous two-phase polymer system. This fraction was found to be enriched 4.1-fold for 5′-nucleotidase activity, but not for other putative plasma membrane markers, (Na+ + K+)-ATPase activity or α-[125I]bungarotoxin binding material. Autoradiographs of α-[125I]bungarotoxin, glycerol-treated (50%, w/w) myotubes showed the plasma membrane blisters to be devoid of reduced silver grains.5′-Nucleotidase was shown to be an ectoenzyme on myoblasts and 5-day-old myotubes and the total cellular activity was present on the cell surface. During the period of myoblast fusion and myotube formation, cell surface activity decreased to a low level while total cellular activity was elevated.  相似文献   

19.
It is postulated that the six conjugated bile acids of most common occurrence in human bile could be analyzed by three enzymic and one chemical assay without any prior chromatographic separation of the bile acids. In health, all bile acids in liver or gall bladder bile are conjugated with either glycine or taurine and have an a-hydroxyl group at the 3 position. In addition, the trihydroxy bile acid, cholic (C) has a 7α- and a 12α-hydroxy group while the dihydroxy bile acids either have a second hydroxyl group at the 7α-position (chenodeoxycholic acid, CDC) or at the 12α-position (deoxycholic acid, DC). Hydroxysteroid dehydrogenases (HSDH) specific for oxido-reductase activity at the 3α-, 7α- and 12α-positions would directly quantify these 3α-, 7α- and 12α-hydroxyl groups in a sample of bile or bile extract. Subsequent data would be used to solve three simultaneous equations yielding solutions for the overall concentrations of conjugated C, conjugated CDC and conjugated DC on the assumption that the overall concentration of lithocholic acid is negligible (< 2 %). A suitable assay for the sulphonate group containing taurine conjugates, such as that described by Christie, Macdonald & Williams, 1975, along with the total bile acid measurement would readily facilitate the estimation of the glycine/taurine (GT) ratio. This ratio applied to the enzymatically derived estimates for conjugated DC, CDC and C would approximate the glycodeoxycholate (GDC), glycochenodeoxycholate (GCDC), glycocholate (GC), taurodeoxycholate (TDC), taurochenodeoxycholate (TCDC) and taurocholate (TC) concentrations. Figures for these concentrations would be based on the assumption that the GT ratio is approximately the same for each bile acid and that all the bile acids are conjugated.  相似文献   

20.
A method was developed for quantitative determination of 5α,7α-dihydroxy-11-ketotetranor-prostane-1,16-dioic acid, the major urinary metabolite of prostaglandins F and F in man. The method was based on the use of the O-methyloxime derivative of [5β-3H; 10,10,12,12-2H4]5α,7α-dihydroxy-11-ketotetranor-prostane-1,16-dioic acid as internal standard and determination of ratios between unlabeled and deuterium-labeled molecules by multiple-ion analysis. Excretion values found for healthy human subjects were: males, 10.8–59.0 μg24 hr (n = 10, mean value, 24.0 ± 17.2 (SD) μg) and females, 7.6–13.6 μg24 hr (n = 10, mean value, 10.5 ± 2.1 (SD) μg).  相似文献   

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