Lineage commitment of HLA-DR/CD38-defined progenitor cell subpopulations in bone marrow and mobilized peripheral blood assessed by four-color immunofluorescence

ONO-9302 [epristeride; (-)-17beta-(tert-butylcarbamoyl)androsta-3,5-diene-3-carboxy lic acid] is a novel inhibitor of steroid 5alpha-reductase. We studied in vitro and in vivo effects of ONO-9302 on the rat prostatic tissue in comparison with those of the anti-androgen allylestrenol. ONO-9302 inhibited the rat prostatic enzyme with an IC50 value of 11 nM, whereas allylestrenol was about 80,000-fold less potent. The growth of ventral prostate, which was induced by the subcutaneous injection of testosterone propionate in the castrated rats, was significantly reduced by ONO-9302 at oral doses of 1-100 mg/kg/day. Allylestrenol showed a significant effect only at a dose of 100 mg/kg/day. In mature male rats, ONO-9302 significantly reduced the ventral prostate weight at doses of 10-100 mg/kg/day and decreased prostatic 5alpha-dihydrotestosterone (DHT) content associated with a rise in testosterone (T) content at doses of 0.1-100 mg/kg/day. Plasma hormone levels (i.e., T, DHT, luteinizing hormone (LH) and follicle stimulating hormone (FSH)) were not altered significantly. Allylestrenol significantly reduced the ventral prostate weight at doses of 10-100 mg/kg/day. However, unlike ONO-9302, allylestrenol reduced both the prostatic DHT and T contents and also lowered plasma T, DHT, LH and FSH levels at a dose of 30 mg/kg/day. These results suggest that ONO-9302 reduces the prostatic growth by inhibiting the conversion of T to DHT in the prostate without lowering blood T level unlike anti-androgen drugs.     

Testosterone acts as a prohormone to stimulate male copulatory behavior in male deer mice (Peromyscus maniculatus bairdi).

Determined the importance of reduced and aromatized metabolites of testosterone for male sexual behavior in 111 male castrated deer mice treated with 5-alpha reductase and aromatase inhibitors. In Exp I, testosterone propionate (TP) activation of male copulatory behavior was blocked by the administration of the 5-alpha-reductase inhibitor 4-androsten-3-17-beta-carboxylic acid (17BC). These treatments also prevented TP stimulation of seminal vesicles and ventral prostate gland weight. The inhibitory effects of 17BC were specific to testosterone, since 17BC did not prevent dihydrotestosterone propionate (DHTP) induction of male sexual behavior or seminal vesicles and ventral prostate gland weight increases. In Exp II, TP activation of male copulatory behavior was prevented by the administration of the aromatase inhibitor 1,4,6-androstatriene-3,17-dione (ATD). The ATD did not interfere with DHTP activation of male reproductive behavior. Also, TP and DHTP stimulation of accessory sex organ weight was not blocked by ATD. It is suggested that metabolism of testosterone to both 5-alpha-reduced androgens and estrogens is obligatory for testosterone to reliably stimulate male sexual behavior in castrated male deer mice. (46 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

PNU 157706, a novel dual type I and II 5alpha-reductase inhibitor

PNU 157706 is a novel dual inhibitor of 5alpha-reductase (5alpha-R), the enzyme responsible for the conversion of testosterone (T) to 5alpha-dihydrotestosterone (DHT). Tested on a crude preparation of human or rat prostatic 5alpha-R, PNU 157706 caused enzyme inhibition with IC50 values of 20 and 34 nM, respectively, compared to the values of 32 and 58 nM shown by finasteride. Furthermore, PNU 157706 was highly potent in inhibiting human recombinant 5alpha-R type I and II isozymes, showing IC50 values of 3.9 and 1.8 nM and, therefore, it was several folds more potent than finasteride (IC50 values of 313 and 11.3 nM), particularly on the type I isozyme. PNU 157706 was shown to have no binding affinity for the rat prostate androgen receptor (RBA 0.009% that of DHT). In adult male rats, a single oral dose of 10 mg/kg of PNU 157706 caused a marked and longer lasting reduction of prostatic DHT than did finasteride (at 24 h inhibition by 89 and 47%, respectively). In prepubertal, T- or DHT-implanted castrated rats, PNU 157706, given orally for 7 days at the dose of 10 mg/kg/day, markedly reduced ventral prostate weight in T- but not in DHT-implanted animals, thus showing to be devoid of any anti-androgen activity. In adult rats treated orally for 28 days, PNU 157706 resulted markedly more potent (16-fold) than finasteride in reducing prostate weight, the ED50 values being 0.12 and 1.9 mg/kg/day, respectively. These results indicate that PNU 157706 is a promising, potent inhibitor of both type II and I human 5alpha-R with a very marked antiprostatic effect in the rat.     

Endocrine properties of the testosterone 5 alpha-reductase inhibitor turosteride (FCE 26073)

Turosteride was tested in a series of studies for its effect on 5 alpha-reductase and for its possible influence on other steroidogenic enzymes and on steroid receptors. The compound was found to inhibit human and rat prostatic 5 alpha-reductases with IC50 values of 55 and 53 nM, respectively, whereas it caused a less marked inhibition of the dog enzyme (IC50 2.2 microM). Turosteride showed no relevant effect on rat adrenal C20,22-desmolase (IC50 254 microM) and human placental aromatase (IC50 > 100 microM), and only at relatively high concentrations it caused inhibition of human placental 5-ene-3 beta-hydroxysteroid dehydrogenase-isomerase (3 beta-HSD-I) (IC50 2.5 microM). Turosteride was found to be a selective 5 alpha-reductase inhibitor showing no noteworthy binding to receptors for androgens (relative binding affinity, RBA, 0.004%), estrogens (< or = 0.005%), progesterone (< 0.005%), glucocorticoids (< 0.01%) and mineralocorticoids (< 0.03%). Its biochemical profile was similar to that of finasteride, whereas 4-MA (17 beta-N,N-diethyl-carbamoyl-4-methyl-4-aza-5 alpha-androstan-3-one) was confirmed to be a non-selective 5 alpha-reductase inhibitor, showing a degree of binding affinity to the androgen receptor (RBA 0.1%) and a marked inhibition of 3 beta-HSD-I (IC50 32 nM). When given orally in immature castrated rats together with subcutaneous testosterone propionate (TP) for 7 consecutive days, turosteride reduced the ventral prostate and seminal vesicle growth promoting effect of TP, with IC50 values of approximately 5 and 6.7 mg/kg/day, whereas levator ani weight was unchanged. In comparison, 4-MA was approx. 3-fold less potent than turosteride in reducing the prostate and seminal vesicle weights and caused a marked reduction of levator ani weight, thus showing its unselectivity.     

Androgenic control of food intake and body weight in male rats.

Conducted 2 experiments with 118 adult Sprague-Dawley rats to compare the effects of androgens with those of estrogens and examine the role of target-tissue metabolism in actions of testosterone on body weight. Castration of adult males produced a delayed (by 1 mo), permanent hypophagia and reduction in weight gain. This contrasted with the rapid, transient hyperphagia and increased weight gain caused by ovariectomy in females. Injections of testosterone propionate (TP) stimulated food intake and weight gain in castrated males. Neither 5alpha-reduction nor aromatization of the testosterone molecule played an important role in the stimulation of these measures by TP. The 5alpha-reduced metabolite of TP, 5alpha-dihydrotestosterone propionate (DHTP), was less effective in increasing eating and weight gain than was TP. Very high doses of TP actually reduced weight gain with prolonged treatment (2-6 wks). It is suggested that this reduced weight gain was due to aromatization of TP to an estrogen. The nonaromatizable androgen, DHTP, did not reduce weight gain even in very high doses, and concurrent progesterone injections reversed the weight-reducing actions of high TP doses. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identification of genes expressed in the rat prostate that are modulated differently by castration and Finasteride treatment

In mammals, testosterone and 5alpha-dihydrotestosterone (DHT) are the principal male hormones (androgens). Testosterone is the most abundant circulating androgen, and is converted in specific tissues to DHT by the 5alpha-reductase enzymes. Although each of these androgens binds to the same receptor protein (androgen receptor, AR), each exerts biologically distinct effects. Theories to explain the specific effects of testosterone and DHT have centered on kinetic differences of binding of androgens to the receptor or differences in the metabolic fates of the two hormones. In the current experiments, differential display PCR (ddPCR) was used to identify genes regulated differently by testosterone and DHT. Adult male rats were treated as follows: castrated, treated with Finasteride (an inhibitor of 5alpha-reductase) or left intact for ten days. RNA was prepared from the dissected prostates of these animals and used for ddPCR. Genes exhibiting four distinct patterns of regulation were observed among the mRNAs. Class 1 genes showed equivalent expression in intact and Finasteride-treated animals, but were absent in castrated animals (mRNAs D1, D2, D6, D10). Class 2 genes showed higher expression in intact animals, intermediate levels following Finasteride treatment, but were absent in castrated animals (mRNA D8). Two classes of gene were particularly intriguing: class 3 showed gene expression only in the intact animal (mRNA D7, D9) and class 4 showed increased gene expression following Finasteride treatment (mRNA D3). While the patterns observed for some of these genes (e.g. D8) suggest that the different biological effects of testosterone and DHT may be due to the lower affinity of the AR for testosterone and limiting tissue concentrations of androgen, our results also suggest that some genes expressed in the rat prostate may be regulated in fundamentally different ways in response to testosterone and DHT.     

Role of estrogens in androgen-induced spontaneous activity in male rats.

Conducted 3 experiments with a total of 63 male and 12 female Sprague-Dawley rats to test the hypothesis that testosterone may be aromatized to an estrogen to stimulate running-wheel activity in rats. In Exp I, aromatizable (testosterone propionate; TP) and nonaromatizable (dihydrotestosterone propionate; DHTP) androgens were compared with estradiol benzoate (EB) for the ability to induce running in castrated males. DHTP had no effect on running. TP increased running, but EB was more than 100 times as effective. Results of Exp II show that relatively small doses of a specific estrogen antagonist, MER-25, attenuated the effects of both EB and TP on male running. Findings from Exp III indicate that the MER-25 did not affect the running of castrated, oil-treated males and did not inhibit the running induced by food deprivation. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of hypophysectomy and prolactin replacement therapy on prostatic response to androgen in orchiectomized rats

The effects of hypophysectomy and prolactin replacement therapy on prostatic response to androgen in orchiectomized rats were studied. Castration 23 days prior to treatment with testosterone propionate (TP), followed by hypophysectomy 13 days before TP treatment, and then treatment with 1 mg TP every other day for 16 days caused a greater decrease in body weight, prostatic weight, and the level of citric acid in the prostate than did TP treatment, castration, and sham hypophysectomy. This suggests the existence of a pituitary factor in the maintenance of prostatic integrity. Prolactin replacement therapy in hypophysectomized, castrated,TP-treated rats significantly (p less than .005) increased the prostatic weight and both the content and concentration of citric acid. The results confirm previously reported observations that the prostatic response to androgens is markedly reduced by hypophysectomy in castrated rats, and that prolactin acts synergistically wtih testosterone in promoting prostatic growth and the concentration of citric acid in the prostate. The direct effects of both hypophysectomy and prolactin replacement therapy on the ventral and dorsolateral lobes of the prostate were also demonstrated.     

Gonadal hormone activation of male courtship ultrasonic vocalizations and male copulatory behavior in castrated male deer mice (Peromyscus maniculatus bairdi).

Examined the influence of testosterone (T), a 5-alpha-reduced metabolite of T (dihydrotestosterone), and an aromatized metabolite of T (estradiol) on 35-kHz ultrasonic calling and copulatory behavior by 72 male deer mice. Daily treatment with T propionate (TP), dihydrotestosterone propionate (DHTP), or estradiol benzoate (EB) restored ultrasonic calling in long-term castrated Ss. Both TP and DHTP restored copulatory behavior, but EB was ineffective. Synergism of EB and DHTP action was observed; when subthreshold doses of EB (1 μg/day) and DHTP (50 μg/day) were administered in combination, ultrasonic calling and copulatory behavior were activated. In relation to other comparative findings, results indicate that the degree to which male sexual behavior is facilitated by 5-alpha-reduced androgens and/or estrogens is influenced by the species and the particular pattern of masculine behavior under consideration. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The regulation of gonadotropin-releasing hormone-induced calcium signals in male rat gonadotrophs by testosterone is mediated by dihydrotestosterone

The biological effects of testosterone (T) may be mediated directly by T or indirectly by its metabolites, dihydrotestosterone (DHT) and estradiol. The present study examined whether the metabolism of T is involved in the regulation of GnRH-induced Ca2+ signaling at the pituitary. In gonadotrophs from castrated rats, a significantly greater percentage of gonadotrophs demonstrated oscillatory Ca2+ responses to 100 nM GnRH than cells from intact rats (72% vs. 24%; P < 0.05). This increase was prevented by the administration of T propionate (0.1 mg/kg x day), DHT benzoate (2 mg/kg x day,), estradiol benzoate (EB; 5 microg/kg x day), or the combination of the above doses of DHT benzoate and EB. In all cases the proportion of gonadotrophs from the steroid-treated rats having oscillatory Ca2+ responses to 100 nM GnRH was between 21-25% (P > 0.05, compared with intact rats). To assess the importance of T metabolism, intact male rats were treated with the aromatase inhibitor letrozole (1 mg/kg x day), the 5alpha-reductase inhibitor finasteride (50 mg/kg x day), or their respective vehicles for 7 days. Letrozole had no effect on GnRH-induced Ca2+ signals, serum LH concentrations, or ventral prostate or testes weight. Finasteride treatment, however, mimicked the effects of castration, with significantly more gonadotrophs exhibiting Ca2+ oscillations in response to 100 nM GnRH than gonadotrophs from the vehicle-treated group (71% vs. 20% respectively; P < 0.05). Finasteride also caused a significant (P < 0.05) decrease in prostatic weight and DHT concentration, but had no significant effect on either prostatic T or serum LH concentrations. These findings suggest that in the intact male rat, the effects of T on GnRH-induced Ca2+ signaling are preferentially mediated via DHT. The results of this study also show that in the absence of androgens, estradiol may regulate GnRH-induced Ca2+ signaling in the male rat pituitary.     

Regulation of oxytocin receptor messenger ribonucleic acid in the ventromedial hypothalamus by testosterone and its metabolites

Oxytocin receptor (OR) binding in the ventromedial hypothalamus (VMH) is regulated by testosterone (T) and its metabolites, estrogen (E2) and dihydrotestosterone (DHT). Previous studies have reported that OR binding increases in the VMH in castrated male rats when they are replaced with T or E2 compared to that in vehicle-treated animals. DHT alone had no effect on OR binding, but when given in combination with E2 appeared to have a synergistic effect. This study was designed to determine whether these effects of steroid hormones on OR binding in the VMH are associated with changes in OR messenger RNA (mRNA) expression. Male rats were castrated or sham operated and given T propionate (TP), E2 benzoate (EB), DHT plus EB, or an oil vehicle. OR mRNA was assessed using a rat complementary RNA OR probe and in situ hybridization techniques. OR binding to tissue slices was quantified autoradiographically using an OR antagonist, [125I]d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)] ornithine vasotocin. These experiments showed that TP and EB increased both OR mRNA and OR binding in the VMH significantly above levels in vehicle-treated animals. However, animals given both EB and DHT exhibited significantly lower OR mRNA expression and OR binding in the VMH compared to those in animals treated with TP or EB alone. These data indicate that increases in VMH OR binding in response to gonadal steroids are accompanied by changes at the mRNA level that correspond well in magnitude and direction with those in the OR-binding sites.     

An oxidative stress-mediated death pathway in irradiated human leukemia cells mapped using multilaser flow cytometry

OBJECTIVE: To develop a pharmacokinetic-pharmacodynamic model that characterizes the conversion of testosterone to dihydrotestosterone (DHT) by 5 alpha-reductase types 1 and 2 and the irreversible inhibition of 5 alpha-reductase by finasteride, a 5 alpha-reductase type 2 inhibitor and by GI198745 (dutasteride), a potent and specific dual 5 alpha-reductase inhibitor. METHODS: Healthy men (n = 48) received doses of 0.1 to 40 mg GI198745 (n = 4 subjects per dose), 5 mg finasteride (n = 8), or placebo (n = 8) in a parallel-group study. Plasma concentrations of GI198745, finasteride, and DHT were measured frequently up to 8 weeks after dosing. Models were fitted with mixed-effects modeling with the NONMEM program. RESULTS: The pharmacodynamics were well described with a model that accounted for the rates of DHT formation and elimination, 5 alpha-reductase turnover, relative capacity of the 2 5 alpha-reductase isozymes, and the rates of irreversible inhibition of one (finasteride) or both (GI198745) types of 5 alpha-reductase. The model indicated that type 2 5 alpha-reductase contributed approximately 80% of plasma DHT. GI198745 was about 3-fold more potent than finasteride on 5 alpha-reductase type 2. Nearly full blockade of both isozymes was achieved at doses of 10 mg or more GI198745, although the potency of this agent on 5 alpha-reductase type 1 was less than on type 2. CONCLUSIONS: A physiologically based model for the turnover and irreversible inhibition of 5 alpha-reductase and for formation and elimination of DHT described the data well. This model helps explain differences in the rates of onset and offset of effect and offers a way to determine the relative potency of the irreversible 5 alpha-reductase inhibitors.     

Cell-type-specific expression of rat steroid 5 alpha-reductase isozymes

The enzyme steroid 5 alpha-reductase (EC 1.3.99.5) is a component of an intercellular signaling pathway that determines cell fate in the primordium of the mammalian reproductive tract. During male phenotypic sexual differentiation, the dihydrotestosterone product of this enzyme binds to the androgen receptor and initiates development of the external genitalia and prostate. Genes encoding two isozymes of steroid 5 alpha-reductase with different biochemical properties and tissue distributions have recently been isolated. In the current study, we utilize in situ hybridization analysis to determine cell-type-specific expression patterns of the 5 alpha-reductase isozyme mRNAs in two androgen target tissues (regenerating ventral prostate and epididymis) and a peripheral tissue (liver). In regenerating ventral prostate, the type 1 mRNA is expressed in basal epithelial cells whereas expression of the type 2 mRNA is largely confined to stromal cells. These results were confirmed by immunohistochemical analysis and are consistent with distinct roles played by the isozymes in the prostate. In the epididymis, both 5 alpha-reductase isozyme mRNAs are expressed in epithelial cells. Only the type 1 mRNA is present in the liver. This mRNA is distributed in a striking spatial gradient extending from hepatocytes surrounding the portal triad (high expression) to those surrounding the central vein (low to absent expression). These findings demonstrate cell-type-specific expression of the steroid 5 alpha-reductase isozymes and underscore their distinct and overlapping functions in androgen physiology.     

Effects of androgens on dietary self-selection and carcass composition in male rats.

In 3 experiments the aromatizable androgen testosterone propionate (TP, .2 mg/day) increased protein (P) and carbohydrate (C) intake and stimulated body weight gain (BWG) in gonadectomized CD-strain male rats. A higher dose (2.0 mg/day) increased P but not C intake and was less effective in stimulating BWG. Postmortem carcass analyses revealed that the elevated P intake of both TP-treated groups was associated with increased carcass P content. The decreased weight of Ss treated with the high dose of TP was due to a reduction in body fat content. The nonaromatizable androgen 5-α-dihydrotestosterone propionate (DHTP, .2 or 2.0 mg/day) also increased P, (but not C intake) and BWG, but it did not alter carcass composition. Unlike TP, the 2 doses of DHTP were equally effective, but neither dose of DHTP was as effective as the low dose of TP in stimulating P and C intake and BWG. Results suggest that (a) androgens can increase selection of dietary P whether or not they exert significant P anabolic effects; (b) DHTP is not the major metabolite responsible for the increases in P and C intake and in BWG caused by TP; and (c) the decreases in C intake and adiposity in rats treated with the high dose of TP may be mediated by aromatized (estrogenic) metabolites of the androgen. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Microsurgical treatment of midfacial tumours involving the skull base

PROBLEM: In rats, immunization with male accessory gland (MAG) extract promotes experimental autoimmune vesicle prostatitis. A specific mononuclear cell-mediated immune response and prostate androgen metabolism impairment in MAG-immunized rats were observed. The possibility that lymphocytic soluble factors (SoFs) can regulate the local steroid metabolism in these rats directly was studied. We investigated whether the SoFs released by MAG-sensitized lymphocytes are capable of modifying the prostatic androgen metabolism and whether they induce histologic lesions "in vivo" when they are inoculated, carried by liposomes, into untreated rats. METHOD OF STUDY: "In vitro" enzymatic [3H]-5 alpha-dihydrotestosterone bioconversion and histologic studies were performed with prostates from SoF-treated rats (LK rats). The obtained 3 alpha/beta-hydroxysteroid-oxidoreductase activities showed that LK rat values were significantly lower than in controls: 79.0 +/- 2.5 vs 158.7 +/- 10.2 pmol/min/mg protein, respectively (P < 0.01). RESULTS: In the histologic studies, LK rat prostates showed focalized mononuclear infiltrates of various degrees, whereas control rats showed non-atypic modification of the gland. CONCLUSION: These results indicate that SoFs (probably total lymphokines) contribute significantly to the pathogenesis of experimental autoimmune prostatitis, involving a biochemical relationship between immune reaction and the androgenic enzymatic inhibition in the prostate.     

Hormonal regulation of chymotrypsin-like esteroproteases in the mouse submandibular gland

The activities of chymotrypsin-like esteroproteases in the mouse submandibular gland were additively induced by 5 alpha-dihydrotestosterone (DHT) and triiodothyronine (T3). Zymograms showed that there are many isozymes whose activities are regulated by DHT and/or T3. Some isozymes seemed to be hormone-independent. Histochemical studies revealed that all these isozymes are localized in the granular convoluted tubules.     

Androgen receptors in the anterior pituitary and central nervous system of the androgen "insensitive" (Tfm) rat: correlation between receptor binding and effects of androgens on gonadotropin secretion

The cytosol fractions of the anterior pituitary, hypothalamus, preoptic area and brain cortex of androgen "insensitive" (Tfm) rats possess androgen receptors. However, in the Tfm rats the androgen binding per mg protein was only 10-15% of that in the corresponding normal littermates (Nl). The physicochemical properties of the androgen receptors in the anterior pituitary of the Tfm rat were indistinguishable from those of the normal rat. Thus, no distinctive differences were observed with regard to electrophoretic mobility in 3.25% polyacrylamide gels, isoelectric point (pI=5.8), binding affinity (KD=1.5 X 10(-9)M), temperature stability, sulfhydryl dependence and steroid specificity. It is, therefore, likely that the very low androgen binding capacity by the anterior pituitary and the central nervous system is due to an extreme reduction in the receptor number rather than to the presence of abnormal receptors. Since in the Tfm animals the androgen receptor number is reduced by 85-90%, it is to be expected that very high doses of androgens would be required to achieve hormonal effects. In fact, low doses of 5alpha-dihydrotestosterone propionate (50 mug/100 g body weight) given sc daily for 12 days had no effect on serum levels of LH and FSH. However, very high doses (2 mg/100 g body weight) of testosterone propionate and 5alpha-dihydrotestosterone propionate, which maintained circulating androgen levels above 20 ng/ml, significantly reduced serum gonadotropin levels in castrated Tfm rats. In normal littermates both low and high doses of the androgens suppressed gonadotropin secretion to low levels. These findings strongly indicate that androgen receptors are essential to androgen action on the anterior pituitary and central nervous system in the rat. The serum levels of testosterone (7.7+/-0.15 (SE) ng/ml) and 5alpha-dihydrotestosterone (0.37+/-0.06 ng/ml) were significantly higher in intact Tfm rats than in normal littermates (2.6+/-0.03 and less than 0.1 ng/ml, respectively). The failure of the elevated concentrations of serum androgens to reduce the high serum levels of LH and FSH in intact Tfm rats is most likely due to the extreme reduction of the androgen receptor number and the consequent insufficient hypothalamic and/or pituitary response to androgens.     

Antigen retrieval in cryostat tissue sections and cultured cells by treatment with sodium dodecyl sulfate (SDS)

BACKGROUND: Steroid 5 alpha-reductase is essential for the intracellular accumulation of dihydrotestosterone (DHT), which mediates androgen effects on target tissue. METHODS: In the present study, we describe the differential expression and cellular localization of 5 alpha-reductase 1 and 2 isoenzymes in the human prostate, and untreated and hormone-resistant prostatic carcinomas. The secretory epithelium of normal and hyperplastic glands showed strong nuclear 5 alpha-reductase 1 reactivity. Accordingly, the DHT forming 5 alpha-reductase process in secretory luminal cell types may be mediated predominantly by the type 1 isoenzyme. The androgen-independent basal cell layer variably expressed type 1 and 2 isoenzymes in nuclear and cytoplasmatic compartments. This suggests that circulating androgens are involved to control the basal cell layer, which represents the proliferative compartment of the human prostate. RESULTS: When compared with benign prostate tissue, increased 5 alpha-reductase reactivity was detected in prostate cancer, particularly in high-grade tumors and androgen-insensitive states of the disease. In cancerous lesions, the type 1 isoenzyme tended to shift to the cytoplasm, while the nuclear staining remained unchanged or slightly increased. Referring to the type 2 isoenzyme, increased cytoplasmatic and nuclear enzyme activity was detected in malignant cells when compared with adjacent benign prostate tissue. Even endocrine differentiated tumor cells that consistently lacked the nuclear androgen receptor variably expressed 5 alpha-reductase immunoreactivity. CONCLUSIONS: Although the functional significance of the differential subcellular localization of type 1 and 2 isoenzymes is currently unknown, the present data suggest that prostate cancer retains the DHT forming 5 alpha-reductase process in high-grade lesions and recurrent disease. Accordingly, circulating androgens may be still significant in these hormone-refractory malignancies.     

DNA-protein interactions in the proximal zeta-globin promoter: identification of novel CCACCC- and CCAAT-binding proteins

The present study assessed whether prenatal androgen and estrogen exposure affected adult spatial learning and hippocampal morphology. Water maze performance, the CA1 and CA3 pyramidal cell field, and the dentate gyrus-granule cell layer (DG-GCL) morphology were assessed at adulthood (70+ days of age) in males, females, androgen-treated (testosterone propionate, TP, or dihydrotestosterone propionate, DHTP) females (2-4 mg/day), estradiol benzoate (EB)-treated females (100 microgram/day), and males treated with the antiandrogen flutamide (8 mg/day). Pregnant rats were injected daily (sc) between Embryonic Day 16 and birth; all pups were delivered by cesarean section. Flutamide-treated males were castrated upon delivery, and adult castrates were used to control for activational effects. Steroid-sensitive sex differences were observed in water maze performance in favor of males. Males had larger CA1 and CA3 pyramidal cell field volumes and soma sizes than females, which were feminized with flutamide treatment. TP and EB, but not DHTP, masculinized CA1 pyramidal cell field volume and neuronal soma size; CA3 was masculinized in both TP- and DHTP-treated females, while EB was ineffective. No effects were observed in cell density, number, or DG-GCL volume or due to adult hormone levels. Thus, prenatal androgens and estrogen influence sex differences in adult spatial navigation and exert differential effects on CA1 and CA3 pyramidal cell morphology. Hence, in addition to the previously reported postnatal component, there is also a prenatal component to the critical period in which gonadal steroids organize the neural mechanisms underlying sex differences in adult spatial ability.     

Influence of RF capacitive heating on the alpha 1-adrenergic receptors of rat prostates

The aim of this study was to find out the influence of radiofrequency (RF) capacitive heating on the alpha 1-adrenergic receptor of rat prostates. The prostates of 30-week-old Wistar rats were submitted to a 1-hour single session of RF capacitive heating at 45 degrees C. The ventral prostates that were submitted to heating were compared to those of other rats that were not submitted to heating. In order to determine the density of alpha 1-adrenergic receptors in rat ventral prostates, binding assays for alpha 1-adrenergic receptor were performed with [3H]prazosin in membrane preparations. The receptor density in the control group was 27.07 +/- 3.75 fmol/mg protein. The alpha 1-adrenergic receptor density (Bmax) in the thermotherapy group was 17.91 +/- 5.15 fmol/mg protein. A remarkable decrease in the density of alpha 1-adrenergic receptors was observed in the rat prostates of the thermotherapy group. In conclusion, the present results demonstrate that heating the rat prostate by RF capacitive heating damages the alpha 1-adrenergic receptors.