BACKGROUND The aim of this study was to determine the effect of the phytotherapeutic agent, Permixon®, on a novel coculture model of benign prostatic hyperplasia (BPH) in an effort to better understand the mode of action of the drug in vivo. METHODS The effect of Permixon®, at the calculated therapeutic concentration, on the activity of 5α‐reductase isoenzymes was evaluated utilizing a pH‐specific assay. Prostate‐specific antigen (PSA) secretions into the medium were measured in the presence and absence of Permixon® and quantified by an ELISA assay. The morphological patterns before and following Permixon® treatment were also examined by electron microscopy. All results were compared to controls. RESULTS Permixon® at a concentration of 10 μg/ml (calculated plasma concentration in patient receiving recommended therapeutic dosage) was shown to be an effective inhibitor of both 5α‐reductase types I and II isoenzymes without influencing the secretion of PSA by the epithelial cells, even after stimulation with testosterone. The morphology of Permixon®‐treated cells was found to be markedly different from that of untreated controls. Cells which had been treated with the drug demonstrated extensive accumulation of lipids in the cytoplasm and widespread damage of intracellular membranes, including mitochondrial and nuclear membranes. CONCLUSIONS Permixon® is an effective dual inhibitor of 5α‐reductase isoenzyme activities in the prostate. Unlike other 5α‐reductase inhibitors, Permixon® induces this effect without interfering with the cells' capacity to secrete PSA, thus permitting the continued use of PSA measurements for prostate cancer screening. Prostate 40:232–241, 1999. © 1999 Wiley‐Liss, Inc.

Glucocorticoid hormones are critical to respond and adapt to stress. Genetic variations in the glucocorticoid receptor (GR) gene alter hypothalamic-pituitary-adrenal (HPA) axis activity and associate with hypertension and susceptibility to metabolic disease. Here we test the hypothesis that reduced GR density alters blood pressure and glucose and lipid homeostasis and limits adaption to obesogenic diet. Heterozygous GRβgeo/+ mice were generated from embryonic stem (ES) cells with a gene trap integration of a β-galactosidase-neomycin phosphotransferase (βgeo) cassette into the GR gene creating a transcriptionally inactive GR fusion protein. Although GRβgeo/+ mice have 50% less functional GR, they have normal lipid and glucose homeostasis due to compensatory HPA axis activation but are hypertensive due to activation of the renin-angiotensin-aldosterone system (RAAS). When challenged with a high-fat diet, weight gain, adiposity, and glucose intolerance were similarly increased in control and GRβgeo/+ mice, suggesting preserved control of intermediary metabolism and energy balance. However, whereas a high-fat diet caused HPA activation and increased blood pressure in control mice, these adaptions were attenuated or abolished in GRβgeo/+ mice. Thus, reduced GR density balanced by HPA activation leaves glucocorticoid functions unaffected but mineralocorticoid functions increased, causing hypertension. Importantly, reduced GR limits HPA and blood pressure adaptions to obesogenic diet.—Michailidou, Z., Carter, R. N., Marshall, E., Sutherland, H. G., Brownstein, D. G., Owen, E., Cockett, K., Kelly, V., Ramage, L., Al-Dujaili, E. A. S., Ross, M., Maraki, I., Newton, K., Holmes, M. C., Seckl, J. R., Morton, N. M., Kenyon, C. J., Chapman, K. E. Glucocorticoid receptor haploinsufficiency causes hypertension and attenuates hypothalamic-pituitary-adrenal axis and blood pressure adaptions to high-fat diet.

One fraction, designated FV-7, in the water soluble ingredient of the pollen extract Cernilton was found to be inhibitory to the growth of a prostate cancer cell line. Characterization of FV-7 by high-resolution mass spectrometry and nuclear magnetic resonance identified the fraction as hydroxamic acid, 2,4-dihydroxy-2H-1,4-benzoxazin-3(4H)-one (DIBOA). To confirm this further, we synthesized an authentic sample of DIBOA and found subsequently that the synthetic DIBOA was structurally indistinguishable from FV-7. Furthermore, in a separate experiment we compared the in vitro effects of FV-7 and DIBOA on the growth of a prostate cancer cell line and found that in both cases the effect was inhibitory and that the inhibition curves obtained for both compounds were virtually identical.

In human prostate, dehydroepiandrosterone (DHEA) is a substrate for two major metabolic pathways that produce functionally opposing sex steroids. In one pathway, DHEA is converted into potent androgens such as testosterone and 5alpha-dihydrotestosterone. In the other, DHEA is metabolized to 7alpha-hydroxy-DHEA (7HD). Recently, CYP7B, a novel P450 enzyme originally characterized in mouse brain and expressed in rodent prostate, has been found to be responsible for all extrahepatic 7alpha-hydroxylase activity. In this study, we have investigated the expression and function of this novel enzyme in human prostate. We have used reverse transcription combined with PCR and mRNA in situ hybridization to determine and localize the expression of CYP7B mRNA in human benign prostatic hyperplasia. High levels of CYP7B mRNA were localized in the epithelial cells together with estrogen receptor beta (ERbeta). 7alpha-Hydroxylation was the major metabolic fate of DHEA in human prostate. Furthermore, we have shown that human prostate epithelial cells in primary culture maintain a high level of 7alpha-hydroxylase activity, which was enhanced by coculture with stroma cells. To investigate the functional relevance of CYP7B expression to sex-steroid action in prostate, we used transient transfections and ligand binding assay to determine the ability of 7HD to bind and activate the sex-steroid receptors: androgen receptor, ERalpha, and ERbeta. 7HD specifically activates ERbeta-mediated transcription, mimicking the effects of 17beta-estradiol, but has no impact on ERalpha and androgen receptor. Given that DHEA, and its sulfate, circulate at micromolar concentrations, there is a clear possibility that CYP7B generates sufficient 7HD to activate ERbeta over and above that achieved with very low concentrations of intraprostatic 17beta-estradiol. In conclusion, our study suggests that CYP7B catalyzes oxysterol 7alpha-hydroxylation within the human prostate epithelium. By this reaction, an ERbeta-specific agonist, 7HD, is produced. Therefore, CYP7B may be a novel regulator of the androgens/estrogenic balance within the prostate.