Effect of hypolipidemia on testosterone-stimulated prostatic growth in castrated rats.

Yamanaka, Hidetoshi; Shimazaki, Jun; Koya, Atsushi; Mayuzumi, Takuji; Imai, Kyoichi; Shida, Keizo

doi:10.1507/endocrj1954.24.213

Cited by 5 publications

(3 citation statements)

References 5 publications

(4 reference statements)

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“…Other hypocholesterolemic agents such as cholestyramine (28), colestipol (20), simfibrate (29) and p-sitosterol (30) have now also been reported to affect the prostate gland. Considering that hypocholesterolemic drugs in general appear to affect the cholesterol-containing enlarged prostate gland and realizing the importance of cholesterol in this organ, it became necessary to study cholesterol metabolism in the prostate gland and its possible regulation by testosterone, a recognized mediator of other prostatic functions.…”

Section: Discussion Swyermentioning

confidence: 99%

Kinetics of Testosterone Induced-Cholesterol Synthesis in Rat Ventral Prostate

Singhal

Bonner

Schaffner

1978

Experimental Biology and Medicine

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It has been well established that under certain conditions testosterone administration may significantly affect the rates of DNA, RNA and protein synthesis in the rat ventral prostate (1-4). Testosterone also maintains the morphology and secretory activity of the prostate gland, both in in vitro and in vivo systems (5-7). On castration, there is rapid regression of the rat ventral prostate including the cessation of secretory function (8). Cholesterol has been found to be one of the major constituents of the prostate secretion (9, 10). In this paper, we are reporting the regulation of cholesterol synthesis by testosterone in the rat ventral prostate. Kinetics of cholesterol synthesis in the ventral prostate following testosterone administration to castrated rats was studied in relation to prostate weight gain, DNA and protein synthesis.Materials and methods. Animals. Groups of six adult male intact and castrated Wistar rats (250-350 g) were maintained on Purina rat chow and water ad libitum and were kept under alternating 12-hr light and 12-hr dark schedule. At necropsy final body weights were determined.Administration of testosterone to castrated animals. Castrated animals were injected subcutaneously with 2 mg of testosterone propionate, dissolved in sesame oil (10 mg/ml), at the same time every day for different periods of up to 14 days.In vitro incorporation of radioactive precursors into cholesterol, proteins and DNA by minced prostate tissues. At various time intervals up to 14 days animals were anesthetized with intraperitoneal injections of sodium barbital and sacrificed by exsanguination. The two lobes of the ventral prostate gland were excised free of the fat covering. The tissues were minced and weighed immediately in tared Teflon test tubes and kept in ice until further use. Approximately 25-35 mg samples of minced tissues were used to study the incorporation of radioactive precursors into cholesterol, proteins and DNA.The radioactive precursors, 2-[14C]acetate (sp. activity 50.3 mCi/mmol), 4,S3H-~-leucine (sp. activity 5 Ci/mmol), and 3H-methylthymidine (sp. activity 6.7 Ci/mmol) were used in these studies to determine their incorporation into cholesterol, protein and DNA, respectively. Tissues were incubated with 2 ml of Hank's Balanced Salt solution supplemented with 0.2% glucose and either 1 pCi/ml of 2-[14C]acetate or 1 pCi/ml of 3Hleucine or 3 pCi/ml of 3H-thymidine (pregassed with 95% 0 2 and 5% C02) at 37" for 2 hr on a constant speed shaker. At the end of the incubation period, the reaction was terminated by instant freezing of the tubes in a dry ice-acetone bath. The radioactivity of cholesterol, protein and DNA in the tissues was then determined.Analysis of radioactivity in cholesterol. The tissues were saponified by the addition of alcoholic KOH to a final concentration of 10% KOH and 50% ethanol (95%) at 75" for 75 min. Unsaponified lipids were pooled by repeated extractions with n-hexane. The hexane extracts were evaporated under nitrogen and digitonin precipitation was carried out accor...

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Section: Discussion Swyermentioning

confidence: 99%

Kinetics of Testosterone Induced-Cholesterol Synthesis in Rat Ventral Prostate

Singhal

Bonner

Schaffner

1978

Experimental Biology and Medicine

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“…In this study, VP was excised separately from sacrificed animals, pooled after removal of surrounding connective tissue, and then weighed. The organ weight is expressed by mg per 100 g of rat body weight at the time of sacrifice [16]. tide chain elongation by the so-called "back up" procedure, according to the procedure already described [15].…”

Section: N 727mentioning

confidence: 99%

A new biodegradable polydepsipeptide microsphere for application in drug delivery systems

Yoshida

Asano

Kumakura

et al. 1990

Colloid & Polymer Sci

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A sequential polydepsipeptide containing a tripeptide sequence L-alanyl-Lalanyl-~ethyl L-glutamyl and an a-hydmxy acid L-lactic acid, poly(Ala-Ala-Glu(OEt)-. Lac), was synthesized to prepare the microspherical particles by the solvent evaporation process. In this case, the solvents play the most important role for the preparation of polydepsipeptide microspheres and, as an example, when 200 mg of the polydepsipeptide dissolved in 10 ml of 98/2 % chloroform/dichloroacetic acid mixture was stirred at 400 rpm and 30 ~ the microspherical particles with mean diameter of 58 ~ were formed after pouring into 200 ml of 1% (w/v) poly(vinyl alcohol) solution. 17 ~-Estradiol was incorporated into the particles, and the resulting particles were found to contain 5 mg of drug per 25 mg of the particle. The in vivo release of drug from the micmspherical formulation was evaluated by measuring the pharmacological influence on rat prostate. It was found that the sufficient amount of drug, keeping the effective pharmacological influence, is supplied during the first 12-week period, followed by an incomplete supplying of drug intil the implant is perfectly degraded in vivo in the 25th week from the start of implantation.

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“…In spite of these mainly negative results, the search continues for useful application of this group of agents in the non-surgical treatment of prostatic disease. For example, Yamanaka et a1 studied the effects of simfibrateinduced hypolipidemia on testosterone-stimulated prostatic growth in castrated rats [15]. Simfibrate induces hypolipidemia by reducing levels of triglycerides and cholesterol in the serum.…”

Section: Introductionmentioning

confidence: 99%

The effects of cholestyramine, colestipol, and ADR‐132 on the rat prostate and dunning R‐3327 adenocarcinoma

Brown

Karr

McGarry

et al. 1983

Journal of Surgical Oncology

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The effects of three compounds known to have hypocholesterolemic activity in several species were investigated on the rat prostate and the hormone-dependent R-3327 rat prostatic adenocarcinoma. Cholestyramine, colestipol, and ADR-132 are bile acid-sequestering anion exchange resins which were fed to separate groups of adult male Copenhagen X Fischer (F1) hybrid rats in doses of 0.25%, 1.00%, and 2.00% of diet. The results indicate that serum cholesterol levels in tumor-bearing rats and controls fed these compounds for 29 days were not reduced. The body and organ weights as well as the histological features of the prostate gland, seminal vesicles, and the R-3327 tumor were unaffected by these agents.

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Effect of hypolipidemia on testosterone-stimulated prostatic growth in castrated rats.

Cited by 5 publications

References 5 publications

Kinetics of Testosterone Induced-Cholesterol Synthesis in Rat Ventral Prostate

Kinetics of Testosterone Induced-Cholesterol Synthesis in Rat Ventral Prostate

A new biodegradable polydepsipeptide microsphere for application in drug delivery systems

The effects of cholestyramine, colestipol, and ADR‐132 on the rat prostate and dunning R‐3327 adenocarcinoma

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