Prostate Of Adult Rats Research Articles

The mechanism of antiandrogenic action of chlormadinone acetate (author's transl)

We tried some animal experiments in order to elucidate the mechanism of antiandrogenic action, especially antiprostatic action of chlormadinone acetate (CMA). CMA inhibited the uptake of testosterone by the prostate. CMA itself was incorporated into the prostate cell selectively and inhibited the binding of cytosol 5α-DHT-recepter (The direct action of CMA at the prostatic cell level). CMA has both the direct and indirect actions on the prostate. The indirect action was mainly due to the acceleration of testosterone metabolic enzyme system in the liver and the inhibition of testosterone biosynthesis in the testis. The prostate of intact adult rat was slightly atrophied by the treatment of a small dose of CMA. On the other hand, the involution of rat prostate was intensified by the additive effect of the indirect action to the direct action of CMA, when a greater dose of CMA was administered to intact adult rats.The study on the changes in plasma hormone-contents and the biochemical finding of hypertrophic nodule suggested that improvement of dysuria of patients with BPH was mainly due to the direct effect of CMA.

The participation of pituitary gland in estrogenic effect on arginase activity in the rat prostates.

Estradiol-17β, estrone, estriol or diethylstilbesterol showed the increase in arginase activity of the dorsolateral prostate of intact adult male rats. Neither castration nor adrenalectomy modified the response of arginase activity by administration of estrogen. However, the arginase activity of the dorsolateral prostate of hypophysectomized male rats was significantly reduced regardless of estrogen treatment. On the other hand, almost the similar decrease was observed in the arginase activity of the ventral prostate from castrated, adrenalectomized or hypophysectomized rats, as well as from intact ones.From these results, it was concluded that the increase in arginase activity of the dorsolateral prostate after estrogen treatment might be due to some indirect effects of estrogen, and that pituitary the gland seemed to be involved in this estrogenic effect.

Intraprostatic Injections of various antitumour compounds into rats: Part II. Chronic effects.

Histopathological studies were carried out at intervals of one, two and three months after a single injection of one of seven antitumour compounds into the prostates of adult male CR rats. The histological findings indicate mainly a long term effect of the compounds tested on the glandular epithelium of the rat prostate. The effect is strictly local and no side effects were seen.

Estradiol-induced synthesis of RNA in rat prostate

Samples of RNA extracted from the prostates of estradiol-treated and intact untreated adult rats were compared by the technique of competitive hybridization. The ineffective competition of unlabeled prostatic RNA from control rats against labeled prostatic RNA from estradioltreated rats suggests that there may be some species of RNA present after estradiol treatment which are absent from the control animals. In contrast, prostatic RNA from untreated animals showed no additional species when compared with RNA from estradiol treated animals.

Androgenic regulation of the concentration of prostaglandin F in the male reproductive system of rats and mice.

Prostaglandin F (PGF) was measured in the testes, epididymides, vasa deferentia, seminal vesicles, coagulating glands, ventral prostate and dorsolateral prostate of adult male rats. Most of the PGF present in the vas deferens was located in its luminal contents but apparently was not associated with spermatozoa. The secretions of seminal vesicles and coagulating glands contained very little PGF. Castration reduced PGF concentration in the vas deferens and seemed to have caused a similar change in the epididymis and the seminal vesicles. Administration of testosterone propionate to castrated rats increased concentrations of PGF in the vas deferens, seminal vesicles and apparently in the epididymis. These observations suggest that the synthesis of PGF in the reproductive system of the male rat is under androgen control. In mice, concentrations of PGF in the epididymis and in the seminal vesicle were increased after castration. However, in both rats and mice the content of PGF in these tissues was reduced in long-term castrates. (Endocrinology95: 1739, 1974)

Studies on the in vivo hormonal control of rat prostatic testosterone 4-ene-5α-reductase activity

Because recent reports indicate that the enzymatic 4-ene-5α-reduction of testosterone is an important step in the expression of androgenic activity in the prostate, we have investigated the effects of several hormonal situations on the activity of this enzyme in adult rat prostate. Both specific (pmol testosterone 5α-metabolites formed/mg protein/60 min) and total (pmol testosterone 5α-metabolites formed/rat prostate/ 60 min) activities were measured. Experimental groups subjected to castration or adrenalectomy showed decreased specific and total activities when compared to intact controls. In the hypophysectomized control group the specific activity was increased while the total activity was decreased as compared to intact controls. Estradiol administration for four days to each of the four groups resulted in decreases in both specific and total activities when compared to their group controls. Testosterone administration for four days to each of the four groups resulted in increases in both specific and total activities as compared to their group controls. Combined estradiol and testosterone administration, when compared to the effects of testosterone alone, resulted in no essential change in the intact group, an increase in the castrated group and decreases in the hypophysectomized and adrenalectomized groups. Ovine prolactin administration alone or in combination with estradiol or testosterone or both resulted in no consistent change in enzyme activity in either the intact or hypophysectomized groups. Our results suggest that a number of hormones can modify the activity of prostatic testosterone 4-ene-5α-reductase activity and hence may influence the growth and activity of the prostate.

Incorporation of 131I-labeled androgen-receptor into nuclei of rat prostates

The 131I-labeled receptor of adult rat prostate showed the same binding attitude toward 5α-dihydrotestosterone as the non-labeled receptor. The 131I-labeled receptor was efficiently incorporated into the chromatin and its non-histon protein and DNA in the form of the complex with 5α-dihydrotestosterone, in contrast to the radioactive receptor alone or 131I-labeled serum protein bound to the androgen.

Intraprostatic injections of various antitumoral compounds into rats.

Histopathological studies were carried out at intervals of one, two and three months after a single injection of one of seven antitumour compounds into the prostates of adult male CR rats. The histological findings indicate mainly a long term effect of the compounds tested on the glandular epithelium of the rat prostate. The effect is strictly local and no side effects were seen.

Some biochemical effects of insulin and steroid hormones on the rat prostate in organ culture.

The effect of various steroids and insulin on expiants of the ventral prostate of adult rats in organ culture was investigated. Testosterone activated the incorporation of labeled precursors into RNA and protein and the formation of 14CO2 from 14C-glucose by expiants. All these effects were mimiced by insulin. The testosterone action was suppressed by cyproterone in vitro. In addition to androgens, glucocorticoids activated the incorporation of 3H-uridine into RNA. Simultaneous addition of testosterone with hydrocortisone or insulin produced an augmented effect on the incorporation of 3H-uridine into RNA which exceeded that resulting from a simple summation of the individual hormone responses. Insulin facilitated likewise the action of testosterone on the incorporation of 14C-amino acids into protein. When all three hormones were added simultaneously to the culture medium the stimulation of the three biochemical parameters was maximal. It was therefore concluded that all three hormones are necessary for an adequate maintenance of the ventral prostate of the rat.

The androgenic action of adrenal implants in the ventral prostate of adult, castrated, and oestrogen-treated rats.

Adrenal implants in the ventral prostate of unilaterally adrenalectomized, castrated rats had no effect on the histological appearance of the ventral prostate after 24 days. When similar rats were treated with polyoestradiol phosphate, PEP, 8 mg/kg, the ventral prostates were clearly stimulated but only in the lobe containing the implant. It is concluded that PEP increases the adrenal secretion of ventral prostate stimulating hormones or makes the ventral prostate more sensitive to such hormones.

Action of cyproterone on the rat prostate in organ culture.

Explants of the ventral prostate of adult rats, were maintained in organ culture with various steroids and insulin. In addition to androgens glucocorticoids and insulin were necessary for the maximal stimulation of the explants as judged by measuring the incorporation of labeled precursors into DNA, RNA and protein and the formation of <sup>14</sup>CO<sub>2</sub> from <sup>1</sup><sub>F</sub>C-glucose by explants. The addition of cyproterone, a steroid with high antiandrogenic potency to the culture medium suppressed the testosterone action, but did not interfere withthe effects of insulin. These findings were taken as a proof of the direct and specific antiandrogenic action of cyproterone on the rat prostate.

Metabolic and enzymatic effects of monoamine oxidase inhibitors with and without hydrocortisone on the accessory sex glands of the rat

Monoamine oxidase inhibitors (MAOI), particularly when administered in combination with hydrocortisone acetate, cause considerable inhibition of the growth of the seminal vesicles, dorsolateral prostates and ventral prostates of immature, adolescent and adult male rats. The above combination increases only the concentration of DNA per g tissue in the accessory sex glands, without affecting other metabolites and enzyme systems (RNA, fructose, acid phosphatase and beta-glucuronidase).

Hormonal influences on the carbonic anhydrase concentration in the accessory reproductive tracts of the rat.

The effects of sex hormones on the carbonic anhydrase activity of the rat accessory organs of reproduction were studied. Ovariectomy causes a marked increase in enzjTne concentration, but does not change the total enzyme content of the uteri, indicating that the normal amount of the enzyme was maintained in uteri atrophied by ovariectomy. Estradiol produces marked decreases of the uterine enzjTne concentration of ovariectomized rats, the extent of which depends upon the dosage. When progesterone is injected along with estradiol, it partially inhibits the effect of estradiol on the uterine enzyme of spayed rats, but progesterone by itself has no effect at all on the concentration of uterine enzyme. Eight and fifteen days after castration, the enzyme concentration is mark-edly increased in the ventral prostates of adult rats but is not changed in the seminal vesicles; sixty-five days after castration, the concentration is decreased in both tissues. Also, in immature rats, castration produces in 10 days a ma...

Basophilia in the rodent prostate.

DURING the course of a cytological investigation of the prostate which is being carried out by one of us (P. L. H. D.), a strong and characteristic basophilia of the epithelial cells of the adult male rat and guinea-pig prostate was noticed after formol-Zenker fixation and staining with Methyl-Green Pyronin1. This basophilia (Fig. 1) is found throughout the cytoplasm except in the ‘clear’ area on the luminal side of the nucleus described by Moore, Price and Gallagher2. (This ‘clear’ area is the region in which the Golgi element probably occurs.) The basophilic material appears to be of the nature of minute granules.