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1.
O.L. Tulp  G.I. Meeker 《Steroids》1976,28(2):239-246
Studies were conducted to determine the fate of 15α-hydroxyprogesterone in human placental tissue. Tritiated 15α-hydroxyprogesterone was perfused through normal human placentas in situ at the time of Cesarean section and incubated with a 10,000x g microsomal supernate of the placenta in vitro. In both systems the substrate, but no additional metabolites were identified. These findings indicate that 15α-hydroxyprogesterone is not metabolized during its passage in the human term placenta, and suggests that because of its fetal origin clinical measurements of 15α-hydroxyprogesterone may provide a valuable index to the status of fetal viability.  相似文献   

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History and ClinicalSigns: Herds infected with Trichomonasfetus have histories of infertility, occasional abortions, and pyometra.GrossLesions: There are no specific gross lesions in the fetus. The fetuses are usually aborted in the first half of gestation and may or may not be accompanied by the placenta.MicroscopicLesions: There are no specific microscopic lesions.CulturalProcedures: It is ordinarily not necessary to culture T.fetus in order to demonstrate its presence in placental fluids and/or abomasal contents.SerologicProcedures: There are no suitable seroligic procedures for diagnosing Trichomoniasis.SpecialProcedures: Wet mounts of abomasal contents and/or placental fluids are examined microscopically for T.fetus.PreferredDiagnosticProcedures: Demonstrate the presence of T.fetus by microscopic examination of wet mounts of placental fluids and/or abomasal contents.  相似文献   

6.
The isolated myenteric plexus-longitudinal muscle of the guinea-pig ilem (GPI) was used as testsystem to study the influence of chronic morphine treatment on the levels of enkephalins, β-endorphin and some of its fragments. The peptides were assayed by means of a combination of high pressure liquid chromatography and radioimmunoassays. It was found that the levels of methionine- and leucine-enkephalin and β-endorphin were not altered by chronic morphine treatment of guinea-pigs invivo nor in GPI exposed to morphine invitro. However, the levels of some β-endorphin fragments i.c. γ-endorphin and des-tyrosine-γ-endorphin were elevated after morphine treatment invitro and invivo respectively. It is suggested that β-endorphin and its fragments are involved in homeostatic processes during development of opiate tolerance.  相似文献   

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Studies were conducted to determine the influence of some LHRH analogues on gonadotropic hormone (GtH) secretion in two species of trout. The observations indicated that synthetic LHRH and various stimulatory LHRH analogues are approximately equipotent in these fish. This is an unexpected result considering the superactive properties of these analogues demonstrated in mammals. An inhibitory LHRH analogue was also tested in the trout with the result that powerful inhibition of LHRH induced GtH release was obtained.  相似文献   

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In the immature rat uterus, high concentrations of androgens competed specifically with estradiol on the estrogen receptor (RE). This competition was stereospecific for C19 steroids bearing a 17β and/or 3 hydroxyl group. Very low affinity ligands, such as testosterone, could not compete with estradiol at equilibrium but decreased the association rate of estradiol on its receptor. High doses (> 0.4mg) of 5 α aihydrotestosterone provoked in vivo as in vitro the nuclear translocation of RE. The nuclear receptor thus formed displayed the same 5.2 S sedimentation constant as that induced by estradiol. We conclude that the weak affinity binding of androgens to the estrogen receptor is sufficient to induce its nuclear translocation in vivo provided androgen concentration is high enough in uterus to occupy the estradiol binding site. Conversely, progesterone which does not bind RE could not provoke its nuclear translocation.  相似文献   

9.
The substrate specificities of the endo-β-N-acetylglucosaminidases from Diplococcus pneumoniae and Streptomyces griseus were compared and found to differ considerably. The enzyme from D. pneumoniae released Asn-GlcNAc-Fuc-containing glycopeptides from exoglycosidase-treated acidic IgM glycopeptides but was limited in its capacity to hydrolyze ovalbumin glycopeptides larger than Asn(GlcNAc)2(Man)5. In contrast, the enzyme from S. griseus hydrolyzed this and larger neutral oligosaccharides but could not hydrolyze the above fucose-containing IgM glycopeptides. Removal of the fucose residue, however, converted the latter to an active substrate for the S. griseus enzyme, thus broadening its substrate range to encompass most of those substrates hydrolyzed by the D. pneumoniae endoglycosidase.  相似文献   

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The effects of danazol on steroidogenesis invitro in the 16–20 week old human fetal adrenal were examined by studying: 1) danazol binding to adrenal microsomal and mitochondrial cytochrome P-450, and 2) enzyme kinetics of danazol inhibition of the adrenal microsomal 21-hydroxylase and the mitochondrial llβ-hydroxylase. The addition of danazol to preparations of adrenal microsomes or mitochondria elicited a type I cytochrome P-450 binding spectrum. Danazol bound to microsomal cytochrome P-450 with a high affinity apparent spectral dissociation constant (Kg) of 1 μM and with a lower affinity K's of 10 μM. Danazol bound to mitochondrial cytochrome P-450 with a Kg of 5 μM. In addition, danazol competitively inhibited the microsomal 21-hydroxylase (apparent enzymatic inhibition constant KI = 0.8 μM) and the mitochondrial 11β-hydroxylase (KI = 3 μM). These findings demonstrate that low concentrations of danazol directly inhibit steroidogenesis in the human fetal adrenal invitro.  相似文献   

12.
Adult beagle dogs, castrated one month previously, were treated with 5α-androstane-3α, 17α-diol (total dose 300 mg) over a period of one month. Examination of the prostate after treatment showed no significant change in size, weight or histological appearance from the castrate dog prostate. Subsequent administration of 5α-androstane-3α, 17β-diol (300 mg) over the same period of time resulted in restoration of the prostate size, weight and histological appearance to that of the normal intact dog prostate. It is concluded that exogenously administered 5α-androstane-3α, 17α-diol does not promote prostatic growth in the castrate beagle dog.  相似文献   

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The effects of intraperitoneal administration of (S)-4-amino-5-fluoropentanoic acid, a mechanism-based covalent inactivator of γ-aminobutyric acid transaminase (GABA-T), on whole brain GABA metabolism in mice were investigated. A dose-dependent and time-dependent irreversible inactivation of GABA-T was observed with a concomitant increase in whole brain GABA levels. The compound exhibited no in vitro nor in vivo time-dependent inhibition of glutamate decarboxylase (GAD), alanine transaminase, or aspartate transaminase (Asp-T). It was, however, a potent competitive reversible inhibitor of GAD and a weak competitive inhibitor of Asp-T. The chloro analogue, (S)-4-amino-5-chloropentanoic acid, was ineffective.  相似文献   

14.
Endometrial concentrations of prostaglandins F2α (PGF2α) and E2 (PGE2) were measured by specific radioimmunoassay in sheep, on day 14 of estrous cycle or pregnancy, during luteolysis (Day 16 of the cycle), and after implantation (Day 23 of pregnancy) : concentrations observed on day 14 of cycle and pregnancy were similar. During luteolysis, on day 16 of cycle, a consistent drop was noticed. If luteal regression did not occur, as a consequence of the presence of an embryo, endometrial concentrations of PGF2α on day 23, were twice those of day 14, and PGE2 remained unchanged. In vitro 2 hour incubations of endometrial caruncular tissue from 14 days cyclic or pregnant ewes resulted in de novo synthesis of PG which could be increased by Arachidonic Acid and inhibited by Indomethacin; during the first 30 min of incubation, the PGF2α synthesis was comparable for both endometrial tissues, whereas PGE2 synthesis was twice as great in pregnant endometrium. Fourteen and 23 day conceptuses had high PGF2α and PGE2 concentrations which were not due to maternal PG sequestration : de novo PG synthesis which could be inhibited by Indomethacin was observed in incubated 14 day old embryos. Treatment of pregnant ewes from day 7 to day 22 after mating, either with Indomethacin (300 mg s.c. daily) or with Acetylsalicylic Acid (1 g I.V. daily) resulted in a sharp diminution of endometrial PG concentration and release, with no apparent effect on the establishment of pregnancy. These results tend to ascribe a less important role to PG during early pregnancy in sheep as compared with rodents, in terms of embryonic growth and implantation.  相似文献   

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The dinoflagellate Glenodiniumhallii was investigated for its sterol composition. Five of the six sterols were isolated and identified as cholest-5-en-3β-ol, (24ξ)-24-methylcholest-5-en-3β-ol, stigmasta-5,22-dien-3β-ol, (22E,24R)-4α,23,24-trimethyl-5α-cholest-22-en-3β-ol, and 4α,23ξ,24ξ-trimethyl-5α-cholestan-3β-ol.  相似文献   

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A new steroid-like compound, Δ1-11-oxa-11-deoxycortisol, was tested in a one-week growth suppression, thymus suppression and adrenal weight suppression bioassay for possible glucocorticoid antagonist activity in vivo. We hypothesized that this compound would have antiglucocorticoid activity based on previous studies of 11-deoxycortisol and Δ1,9(11)-11-deoxycortisol, which were optimal glucocorticoid antagonists in vivo in adrenalectomized rats, but which lost antiglucocorticoid activity in intact animals, apparently due to adrenal 11β-hydroxylation. Thus, Δ1-11-oxa-11-deoxycortisol, a compound which cannot undergo llβ-hydroxylation, was synthesized and tested as an antiglucocorticoid. This analog had an affinity for the rat thymus glucocorticoid receptor similar to that of its parent compounds (Ki 0.9-3.1×10?7M). A dose of 1 mgrat antagonized the effect of 15μg of dexamethasone in the growth suppression assay (p<0.05) and in the thymus suppression assay (p<0.06), but did not antagonize dexamethasone-induced adrenal weight suppression. Δ1-11-oxa-11-deoxycortisol did not exhibit glucocorticoid activity in any of the three assays. These data suggest that Δ1-11-oxa-11-deoxycortisol may be a pure competitive antagonist of dexamethasone.  相似文献   

17.
The effects of estradiol-17β treatment on plasma lipid levels, liver lipid and glycogen reserves were examined during different phases of the reproductive cycle in goldfish, Carassiusauratus. Estrogen therapy resulted in increased plasma and hepatic lipid levels except during the spawning season. Hepatic glycogen deposits were depleted by estradiol injections during all seasons. Treatment of fish with the estrogen antagonist, CI-628, during the spawning season caused a reduction in plasma and liver lipid levels. Electrophoretic studies conducted during the post-spawning season showed that estrogen induces the appearance of a specific lipoprotein, probably a yolk precursor, in the serum and liver of goldfish.  相似文献   

18.
I.C. Campbell  A. Todrick 《Life sciences》1976,18(10):1091-1097
4-Methyl-α-ethyl-tyramine and its 4, α-dimethyl analogue release 5-HT from human blood platelets invitro. At lower concentrations they inhibit the uptake of 5-HT into platelets. Tricyclic antidepressant drugs do not block 5-HT release by these compounds. On removal of the depletor, platelets recover their ability to take up 5-HT; platelets preloaded with exogenous 5-HT lose the same proportion of amine as those containing only endogenous 5-HT. Tetrabenazine behaves similarly, but its actions are partial, whereas those of the tyramines are more complete. The temperature dependence of spontaneous and drug-induced 5-HT release has been measured. The results are discussed in terms of the action of these drugs and with special reference to the use of human blood platelet as a model of a 5-HT-containing nerve ending.  相似文献   

19.
Sucrose and 1,2-O-isopropylidene-α-d-glucofuranose (1) were oxidised with bromine in aqueous solution at pH 7 and room temperature. The resulting keto derivatives were converted into their more-stable O-methyloximes, which were characterised by spectroscopic and chromatographic methods. Oxidation of 1 occurred at C-3 and C-5, with a preference for C-5. In the sucrose derivatives isolated after oxidation, those having a keto group in the glucopyranosyl moiety preponderated. The axial fructofuranosyl aglycon protects position 3 in the glucopyranosyl group and oxidation occurs only at C-2 and C-4. Small amounts of sucrose oxidised at C-3 in the fructofuranosyl moiety were also found.  相似文献   

20.
Three DNA-dependent RNA polymerases (EC 2.7.7.6), P-I, P-II and P-III, have been isolated from the sonicated nuclear extract of vegetative amoebae of Dictyostelium discoideum by phosphocellulose chromatography. P-I was inhibited by α-amanitin, while P-II and P-III were not. Rifampicin did not prevent all the polymerase activities. These polymerases were more active in the presence of Mg2+ than Mn2+. P-III was reduced in the enzyme activity by being passed through DEAE-Sephadex column and not obtained from the nuclear extract of amoebae at the culmination stage during morphogenetic development.  相似文献   

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