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1.
Isoenzymes of glutathione transferase in rat small intestine.   总被引:2,自引:1,他引:1       下载免费PDF全文
The role of plasminogen activators (PAs) as potential mediators of involution of the rat ventral prostate was investigated by using an approach involving the administration in vivo of anti-PA drugs. The prostates of castrated rats, which had been injected daily for 7 days with the anti-PA drugs 6-aminohexanoic acid, tranexamic acid, aprotinin and cortisol, were assayed for PA activity, weight and cell number. In the prostates from the castrated controls, there was a 10-fold increase in the mean PA activity and a 7-fold decrease in cell number relative to that of the non-castrated animals. Although this rise in enzyme activity could be decreased to some extent by all the drugs except aprotinin, only treatment with high doses of tranexamic acid or cortisol had a statistically significant effect. A similar pattern was observed with respect to the relative potency of the drugs in preventing the loss of prostatic weight and cell number after castration. The effects of cortisol were dose-dependent, with complete inhibition of both the rise in PA activity and cell loss occurring at a dose of about 15 mg/day. Since the concentration of the principal intranuclear androgen, dihydrotestosterone, was the same in the prostates from treated and untreated castrated rats, the effects of cortisol are not due to increased retention of this androgen. Rather, the high inverse correlation (r = 0.86) between the cellular concentration of PA activity and the cell population of the prostate implies that PAs are directly associated with prostatic involution and that cortisol, and to a lesser extent tranexamic acid, blocks the involution process through inhibition of PAs.  相似文献   

2.
The concentration of dihydrotestosterone was measured by radioimmunoassay in nuclear and cytoplasmic extracts from rat ventral prostates. In the regenerating prostates of castrated rats treated with dihydrotestosterone for 4 days, the nuclear concentration of this steroid increased from approx. 70nM to 800nM as a linear function of the injected dose, whereas the cytoplasmic concentration remained relatively constant (70-130nM). Isotope-exchange measurements of nuclear androgen receptors by using [3H]methyltrienolone indicated that, although the concentration of nuclear dihydrotestosterone was several-fold higher than the concentration of androgen receptors, they were logarithmically related. The recruitment of prostatic cells into the growth fraction and the stimulation of 5 alpha-reductase activity were more directly correlated to the nuclear concentration of androgen receptors than to the total nuclear concentration of dihydrotestosterone. Maximal restoration of a specific isoenzyme of acid phosphatase ws achieved when approx. 2000 androgen receptors were present in the prostatic nuclei; higher concentrations of nuclear androgen receptors were associated with decreased amounts of this enzyme. Hence the results imply, first, that the total amount of dihydrotestosterone accumulated by nuclei is not a direct consequence of carrier-mediated transport by androgen receptors, and, secondly, that, whereas acid phosphatase may be differentially controlled by androgens in the regenerating prostate, increases in the amount of cell proliferation and 5 alpha-reductase activity directly parallel increases in the nuclear concentration of androgen receptors.  相似文献   

3.
4.
The antifibrinolytic activity of cytosol from Dunning R3327H rat prostate tumors was studied. The prostate tumors from rats treated with D-Trp6-LH-RH had 2.5 times lower plasminogen activator activity than tumors from untreated rats. This was due to the presence of an inhibitor of plasminogen activator as well as a reduction in residual activity of plasminogen activator(s). Only the cytosolic extracts from prostate tumors of rats treated with D-Trp6-LH-RH contained this inhibitor. The purified inhibitor (m.w. 21,000), formed a complex with urokinase and partially purified plasminogen activator(s) from prostate tumors of untreated as well as D-Trp6-LH-RH treated rats. The increase in antifibrinolytic activity after treatment with LH-RH analogs may be an important factor in reducing the invasiveness of the prostate tumor.  相似文献   

5.
Male mice were castrated at 2 months of age and a pellet of testosterone propionate was implanted subcutaneously ten days later. After 14 days, normal, castrated and androgen treated mice were autopsied simultaneously. The kidneys of each group were homogenized, pooled and fractionated by centrifugation into the various subcellular components. The alkaline ribonuclease and phosphatase activities were localized in the microsomal fraction and changed in inverse relationship to the previously observed changes in the rate of protein biosynthesis and the concentration of microsomal and polysomal RNA induced by castration and androgen administration. Esterase activity also was localized in the microsomal fraction and its specific activity decreased after castration and was restored to normal by testosterone. The activities of acid ribonuclease, acid phosphatase and the several marker enzymes (glucose-6-phosphatase, nucleotidase, succinic dehydrogenase and glucose-6-phosphate dehydrogenase) changed in direct proportion to the changes in weight of the kidney after castration and androgen stimulation.  相似文献   

6.
Starvation of rats for 48 h increased the activity of PDH (pyruvate dehydrogenase) kinase 2.2-fold in extracts of liver mitochondria, 2.9-fold in PDH complex partially purified therefrom by fractional precipitation, and 5-fold in PDH complex partially purified by gel filtration on Sephacryl S-300. A protein fraction was separated from PDH complex in extracts of rat liver mitochondria by gel filtration or fractional precipitation, which increased the activity of PDH kinase in rat liver and pig heart PDH complexes. The activity of this protein fraction was increased approx. 2.5-fold by 48 h starvation of rats. With highly purified pig heart PDH complex it was shown that the protein fraction increased the Vmax. of the PDH kinase reaction 35-fold (fraction from fed rats) or 82-fold (fraction from starved rats); starvation had no effect on the concentration of protein fraction required to give 0.5 Vmax. Evidence is given that the increase in PDH kinase activity effected in extracts of liver mitochondria by starvation is due to increased activity of kinase activator protein, which is tightly bound by rat liver PDH complex and not removed by a single gel filtration. With pig heart PDH complex, increased PDH kinase activity was retained after gel filtration of an admixture with kinase activator protein from starved rats, but was restored to the control value by a second gel filtration; the alterations in PDH kinase activity were associated with obvious changes in protein bands in SDS gels.  相似文献   

7.
Protein kinase C (PKC) isoenzymes are involved in cell function, growth, apoptosis and neoplastic transformation in the prostate gland. We detected by means of Western blot the expression of the classical alpha and beta1, the novel epsilon and the atypical zeta isoforms of PKC in ventral prostates from rats with different extents of plasma testosterone levels and/or androgen imprinting on the gland. The expression of the four isoforms decreased in 5-day castrated rats showing apoptotical regression of the gland and a drastic reduction of circulating testosterone. However, the expression of PKC isoenzymes (alpha, beta1, epsilon ) increased in prostates from pubertal (35-days old) rats that are characterized by relatively low but extremely bioactive testosterone plasma levels. Treatment of adult rats for 14 days with flutamide (daily s.c. injection of 15 mg/Kg B.W.) resulted in increased expression of the four isoenzymes; it occurred in the presence of increased (normal rats) or drastically reduced (rats castrated after 9 days of flutamide administration) levels of plasma testosterone conceivably through a direct effect of this nonsteroidal antiandrogen on prostate cells. Measurements of PKC(alpha) activity were in agreement with the observations on protein expression and showed that flutamide (that is extensively used in the treatment of advanced prostate cancer) elicits some impairment in the mechanisms of translocation of this isoform from the cytosol to the membrane. Thus, in addition to the possibility of direct effects of flutamide upon the rat prostate, we present evidence that the levels of circulating androgens and/or their bioactivity in the gland regulate the expression of various important PKC isoforms.  相似文献   

8.
9.
S Batra  J Alenfall 《Life sciences》1992,51(15):1211-1215
The effect of orchiectomy on peripheral benzodiazepine receptors (PBZr) in the rabbit prostate was studied. The mean PBZr density in the mitochondrial fraction isolated from prostates of intact (non castrated) rabbits was 4066 fmol/mg protein which following castration increased to 7236 fmol/mg protein (p less than 0.005). The apparent dissociation constant (KD) of prostatic PBZr was higher in castrated rabbits (4.2 nM) than in intact animals (2.7 nM). These data suggest a role of androgen in the regulation of prostatic PBZr.  相似文献   

10.
1. Castration of adult rats resulted in marked decreases in the amounts of putrescine, spermidine and spermine in the ventral prostate gland. Spermidine concentrations decline rapidly over the first 11 days after androgen withdrawal, reaching a value of only 12% of normal controls. Spermine concentrations diminish more slowly, reaching 24% of normal within 11 days. The spermidine/spermine molar ratio falls from 0.9 to 0.46 under these conditions. Putrescine concentrations decrease by 70% at 7 days after castration and then remain constant for some days. 2. After daily injections of testosterone propionate to rats castrated 7 days previously, prostatic spermidine and putrescine concentrations increase significantly within 24h; normal or even greater values are observed within 8 and 4 days respectively. In contrast, the spermine concentration does not increase until 5 days after commencement of androgen treatment. 3. The activities of two enzymes involved in polyamine biosynthesis (ornithine decarboxylase and a putrescine-activated S-adenosyl-l-methionine decarboxylase system) were greatly decreased soon after castration: after 7 days the respective values were 15% of normal for ornithine decarboxylase and 7% of normal for putrescine-dependent decarboxylation of S-adenosyl-l-methionine. Injection of testosterone propionate into animals castrated 7 days previously induced a rapid increase in both enzymic activities: ornithine decarboxylase was doubled in 6h, and increased three- to four-fold within 48h, whereas the putrescine-dependent decarboxylation of S-adenosyl-l-methionine doubled in 3h and increased tenfold within 48h of commencement of daily androgen treatments. 4. The activity of these enzyme systems was very low in the ventral prostates of hypophysectomized rats and was increased by administration of testosterone in a manner similar to that found in castrated rats. 5. Alterations in the activity of two ventral-prostate enzymes involved in ornithine production (arginase) and utilization (ornithine–2-oxoglutarate transaminase) that result from changes in the androgenic status of rats are described. 6. The findings presented suggest that the activities of ornithine decarboxylase and the putrescine-dependent S-adenosyl-l-methionine decarboxylase system, rather than ornithine concentrations, are rate-limiting for the formation of putrescine and polyamines in rat ventral prostate. 7. The relation of polyamines to androgen-induced prostatic growth is discussed with particular reference to the biosynthesis of proteins and nucleic acids.  相似文献   

11.
M de M Fencl  C A Villee 《Steroids》1973,21(4):537-552
Prostatic tissue from normal, estradiol-treated, and castrated rats was incubated with testosterone, and the metabolites formed were studied. Pretreatment with estradiol-17β did not affect the total amount of testosterone metabolized per unit weight of tissue. In contrast, the total amount of testosterone metabolized was significantly reduced following castration. The formation of dihydrotestosterone (17β-hydroxy-5α-androstan-3-one; DHT) was not affected by treatment with estradiol, but was significantly reduced by previous castration. Estradiol treatment enhanced the formation of 17-keto metabolites of testosterone by the prostate, giving lower 17-hydroxy to 17-keto ratios than incubations with prostates from control or castrated rats. These results are consistent with the theory that the mechanisms leading to the involution of prostate after estradiol treatment and after castration are different.  相似文献   

12.
The regression of the ventral prostate, after a rat is deprived of androgens by castration, is accompanied by a marked decrease in the prostate's ability to synthesize RNA and major proteins. Surprisingly, in vitro translation of prostate RNA, isolated from rats 2 days after castration, detects four proteins with Mr of approximately 29,000, 37,000, 46,000, and 49,000 whose message levels increased 4- to 12-fold compared to results from normal rats. According to cDNA dot hybridization analysis, the increase after castration in the level of the 29-kDa protein-mRNA (per unit amount of DNA) was reversed within 6 h by androgen treatment of castrated rats. In contrast, the level of a mRNA in male rat liver, which hybridized to a cloned probe for the prostate 29-kDa protein-mRNA was reduced by castration and increased by androgen treatment. During an in vitro incubation, the ventral prostates of normal rats were much less efficient than the prostates of rats castrated 2 days earlier in synthesizing a 29-kDa protein. Despite the fact that androgenic manipulation of rats induced very rapid and significant changes in the production of the 29-kDa protein and in the level of its mRNA, the cellular level of this protein in the prostate, as determined by radioimmunoassay, was maintained at near normal values throughout the 2-week experimental period. Thus, the prostate appears to have a mechanism, based on androgen repression of certain genes, to maintain the cellular levels of the 29-kDa protein and possibly other structurally or functionally important proteins during both the periods of androgen-dependent growth and the castration-induced regression. The loss of such a regulatory mechanism may result in androgen-independent abnormal prostate growth.  相似文献   

13.
The histochemical distribution of six glycosidases (N-acetyl-beta-glucosaminidase, beta-galactosidase, beta-glucuronidase, alpha-galactosidase, alpha-mannosidase and alpha-fucosidase) was investigated in the prostate, glandula vesicularis and glandula bulbourethralis of castrated and non-castrated adult boars. The functions of the glycosidases in the male accessory sex glands of the boar and their androgen dependence are discussed briefly.  相似文献   

14.
Whether or not various cytosolic protein kinases (and especially the type I cAMP-dependent protein kinase) of rat ventral prostate are specifically regulated with respect to total activity or specific activity by androgen has been investigated. Following androgen deprivation, the total activity per prostate of cAMP-dependent protein kinase (with histone as substrate) changed little at 24 h, declining by about 20% at 96 h. Under these conditions, its specific activity remained unaltered at 24 h, but was markedly enhanced at 96 h postorchiectomy. Type II cAMP-dependent protein kinase in rat ventral prostate cytosol was the only form of cAMP-dependent protein kinases present as determined by measurement of catalytic activity as well as [32P]-8-N3-cAMP binding to the regulatory subunits. There was no alteration in the distribution of the isoenzymes of cAMP-dependent protein kinases or the response of these kinase activities to cAMP owing to castration of animals. The prostatic cytosol also contains free regulatory subunit (with molecular weight similar to that of regulatory subunit R1) which coelutes with type II cAMP-dependent protein kinase. This finding was confirmed by using [32P]-8-N3-cAMP photoaffinity labeling of cAMP-binding proteins. With respect to cAMP-independent protein kinase (measured with dephosphophosvitin as substrate), a decline of 31% in its specific activity was observed in cytosol of prostates from rats castrated for a period of 24 h without significant further change at later periods following castration. However, there was a marked progressive reduction in total activity of this enzyme per prostate (loss of 72% at 96 h postorchiectomy). The increase in specific activity of cAMP-dependent, but not cAMP-independent, protein kinase in the face of decreasing total activity in the cytosol at later periods of castration (e.g., at 96 h) may reflect a slower loss of the former enzyme protein than the bulk of the cytosolic proteins. Administration of testosterone to castrated animals prevented these changes. These data do not indicate a specific regulation by steroid of the type I cAMP-dependent protein kinase in the prostate. Rather, the cAMP-independent protein kinase (with dephosphophosvitin as substrate) appears to be modulated by the androgenic status of the animal.  相似文献   

15.
Aldehyde dehydrogenase (ALDH, EC 1.2.1.3) of the human prostate was the subject of investigation in this study. The possible physiological role of aldehyde dehydrogenase in the human prostate might be to detoxify aldehydes arising from the oxidation of the polyamines via monoamine or diamine oxidases. The specific activity of the enzyme with 1 mM propionaldehyde as substrate and 0.5 mM NAD at pH 7.4 in the control normal prostates and prostates afflicted with the disease, benign prostatic hyperplasia (BPH), was 26.06 +/- 2.96 and 5.17 +/- 0.48 nmol/g prostate per min, respectively. When 100 microM gamma-aminobutyraldehyde was used as a substrate, the specific activity in the normal controls and prostates with benign prostatic hyperplasia was 19.80 +/- 1.33 and 2.95 +/- 2.46 nmol/g prostate per min, respectively. Upon isoelectric focusing of the extracts of the control prostates when the gels were developed for aldehyde dehydrogenase activity, there were three aldehyde dehydrogenase activity bands visible, pI 4.9 (mitochondrial), 5.4 (cytosolic) and about 6.0-6.5, on the IEF gels developed with gamma-aminobutyraldehyde as a substrate. With the extracts of prostates with benign prostatic hyperplasia the pI 4.9 band was significantly reduced, the pI 5.4 band enhanced and the approx. pI 6.0 band was not detectable on the IEF gels with propionaldehyde as a substrate. There was no detectable aldehyde dehydrogenase activity in the extract of the prostate with cancer on IEF gels nor in the activity assays with propionaldehyde or gamma-aminobutyraldehyde as substrates.  相似文献   

16.
性激素对血红素氧化酶在大鼠前列腺腹侧叶表达的影响   总被引:1,自引:0,他引:1  
Tian J  Zheng Y  Yang C 《生理学报》2004,56(1):54-59
血红素氧化酶(heme oxygenase,HO)是产生内源性一氧化碳(carbon monoxide,CO)的限速酶,最近发现内源性CO在调节平滑肌张力方面起重要作用。而人的良性前列腺增生(benign prostates hyperplasia,BPH)所致的膀胱出口梗阻与前列腺平滑肌张力有密切关系,但还不清楚内源性HO/CO系统是否介导了前列腺平滑肌的活动。为了观察性激素对大鼠前列腺腹侧叶中血红素氧化酶-1(heme oxygenase-1,HO-1)和血红素氧化酶-2(heme oxygenase-2,HO-2)基因表达的影响,我们采用睾丸切除术建立雄性SD大鼠去势模型,用RT-PCR方法观察HO-1和HO-2的转录水平,应用免疫组织化学结合图像分析技术,观察去势、外源性雄激素和雌激素对前列腺腹侧叶中HO—1和HO-2蛋白水平的影响。结果表明,HO-1和HO-2在正常大鼠前列腺腹侧叶中都有表达,腺上皮细胞和纤维平滑肌间质呈现HO-1的免疫活性,HO-2的免疫染色仅在腺上皮细胞内检测到;去势组HO-1的mRNA和蛋白表达水平显著低于正常对照组(P<0.01):外源性给予雄激素组和雌激素组的HO-1表达水平明显增高(P<0.01),且雌激素主要增加前列腺纤维平滑肌间质的HO-1表达:HO-2在各组间的表达无明显差异(P>0.05)。这些结果提示,性激素对HO-1有诱导作用,但对HO-2无明显的影响,因此推测一氧化碳-血红素氧化酶(CO—HO)  相似文献   

17.
The levels of polyamines and their synthesizing enzymes in squamous cell carcinoma of prostate implanted in intact as well as castrated male rats were determined after certain hormonal manipulations. The tumour was found to grow with an identical rate in non-castrated and castrated rats. Polyamine content and activities of polyamine synthesizing enzymes in the tumour were found to be much lower compared to their values in ventral prostate. Moreover, the levels of these parameters were comparable in tumours whether implanted in non-castrated or gonadectomized animals. The sequential analyses of putrescine and spermidine and activities of L-ornithine decarboxylase and S-adenosyl-L-methionine decarboxylase of tumours at different time intervals showed a significant reduction in their levels at 30 days compared to 10 days post implantation in non-castrated as well as castrated rats. Daily intramuscular administration of tumour-bearing intact or castrated animals with testosterone (50 micrograms/g), beta-estradiol (2 micrograms/g) or cyproterone (12.5 micrograms/g) for 10 days did not influence polyamine metabolism in tumour tissue. However, either beta-estradiol and cyproterone treatments or castration were found to decrease polyamine synthesis in ventral prostate. At the same time, the testosterone replacement therapy did not allow polyamine levels or activities of polyamine synthesizing enzymes to decline in the ventral prostate of castrated rats. Our results demonstrated that contrary to ventral prostate, the polyamine metabolism in squamous cell carcinoma of prostate is independent of hormonal control. The loss of hormonal sensitivity of polyamine metabolism in the prostatic tumour could be the result of qualitative changes that occurred during transformation.  相似文献   

18.
Pharmaceuticals such as finasteride and alpha blockers are used to treat symptoms of benign prostatic hyperplasia (BPH) and are known to cause severe adverse reactions. Accordingly, a search for safer, natural products has been undertaken. Two natural agents (nutraceuticals) have come under recent scrutiny; because natural products, in general, often have evidence of long-term safety. The present study compares the in vivo effects on androgen-induced prostatic enlargement in rats of two nutraceuticals – the widely recognized Saw Palmetto (Serenoa repens) and the less well-known Cernitin (defined pollen extract). Non-castrated rats, had a mean prostate weight of 124 mg ± 8.8 (S.E.M.) compared to the 24.5 mg ± 1.9 (S.E.M.) of the castrated rat followed under the same regimen (p < 0.01). When castrated rats were given testosterone, the mass increased significantly to 250.0 mg ± 31.7 (S.E.M.) (p < 0.01). In the five remaining groups, castrated rats receiving testosterone were given finasteride, an extract of Saw Palmetto, crushed whole berry derived from Saw Palmetto fruit, a water soluble and fat soluble extract of Cernitin or a combination of the Saw Palmetto extract and Cernitin. All treatments decreased the size of the prostate to roughly the same size as in the non-castrated rats, a size that was significantly smaller than castrated rats treated with testosterone in the same manner (p < 0.01). A second study examining non-castrated rats treated with very high doses of testosterone showed similar results. In both studies, the nutraceuticals generally decreased body weight. In conclusion, these studies show the ability of Saw Palmetto (whole berry and extract) and Cernitin to influence prostatic hyperplasia via effects on androgen metabolism.  相似文献   

19.
TIMPs in the prostates of male and female gerbils and evaluated the effects of testosterone on the expression of these enzymes. Ventral prostates from male gerbils that were either intact or had been castrated for 7 or 21 days, along with prostates from female gerbils that were either intact or had been treated with testosterone for 7 or 21 days, were submitted to histological, stereological and immunohistochemical analyses. Stereology of prostatic components showed significant alterations of tissue compartments in the ventral male prostate after castration, especially after 21 days, with a significant increase in stroma. Administration of testosterone led to disorganization in the female prostate, with a significant increase in collagen fibers and smooth muscle cells after 21 days, along with the development of epithelial lesions such as PINs. MMP-2 increased after 21 days of castration in males; however, the TIMP-2 immunoreaction for this group was weak or absent. In females, the expression of MMP-2 appeared to decrease after 7 days of treatment with testosterone, but after 21 days, both epithelium and stroma showed a stronger reaction for MMP-2 than the controls. The expression of TIMP-2 in the treated females was similar to its expression in the castrated males. We conclude that the distribution of MMPs and TIMPs in both male and female prostates is altered by androgen manipulation, but the mechanism of stromal regulation appears to be distinct between genders because both the lack of T in castrated males and the excess levels of T in treated females lead to the same effect.  相似文献   

20.
Electrophoretic analysis of plasminogen activators from pig heart, human uterus, human plasma and human melanoma cells was performed in SDS-polyacrylamide gradient slab gels containing plasminogen and casein. Direct visualization of activator activity bands in polyacrylamide gels was achieved after removal of SDS, incubation in buffer, and staining with Coomassie brilliant blue. Tissue activator extracted from pig hearts displayed a molecular weight of 72000 and migrated similarly to activator secreted by human melanoma cells and to one activator component present in extracts of human uterus. Immunoadsorption experiments with melanoma cell activator antiserum indicated that these 72-kDa activators are all related immunologically. Human uterus also contained a second activator component with a molecular weight 55000, which migrated similarly to a higher molecular weight component of urokinase and cross-reacted with urokinase antiserum. We conclude that the 72-kDa uterine activator component represents a tissue activator and the 55-kDa component represents a urokinase-like activator. A euglobulin solution from venous occlusion plasma displayed multiple bands of plasmin activity in the Mr range 85000-96000. Two activator components were also present, one of Mr 72000 and another of Mr 62000. The 72-kDa euglobulin activator was adsorbed by MCA antiserum, and we conclude that this component represents vascular activator. The 62000 activator also had weak plasminogen-independent caseinolytic activity and was not affected by either melanoma cell activator or urokinase antisera. Conclusions concerning its identity cannot be made at this time.  相似文献   

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