Search Results

You are looking at 71 - 80 of 272 items for :

Clear All
Restricted access

E. D. Lephart, E. R. Simpson and W. H. Trzeciak

ABSTRACT

To investigate the effects of sex hormones on 5α-reductase, we examined 5α-reductase mRNA content and enzyme activity in the adrenal cortex of peripubertal male and female rats. In male rats, the influence of castration or hormone-replacement treatment with dihydrotestosterone (5α-DHT) on 5α-reductase was assessed. To stimulate ovarian sex hormone production in immature female rats, the effect of a single injection of 5 IU pregnant mare serum gonadotrophin (PMSG) on 5α-reductase was examined. The efficacy of the treatments was demonstrated by measuring serum LH and ventral prostate weight in male rats, and serum oestradiol and ovarian weight in female rats. Growth hormone was also measured across all treatments in male and female rats. Adrenal 5α-reductase mRNA levels were determined by RNA blot analysis utilizing a rat 5α-reductase cDNA as probe. 5α-Reductase enzyme activity was estimated by isolating [ 3H]5α-DHT by thin-layer chromatography after incubation with [3H]testosterone. The identity of the [3H]5α-DHT formed was demonstrated by recrystallization of the derivatized DHT to constant specific activity. In controls, adrenal cortical 5α-reductase mRNA content was nearly four times higher in immature female rats compared with intact peripubertal males. Castration resulted in a sevenfold increase in adrenal 5α-reductase mRNA content compared with that in intact controls, while in DHT-injected castrated animals the mRNA level was nearly undetectable. The content of adrenal 5α-reductase mRNA in anoestrous rats was nearly four times higher than in PMSG-treated animals. Adrenal 5α-reductase activity was higher in immature female rats than in intact peripubertal males. Castrated rats displayed more than a threefold increase in 5α-reductase activity over that of controls, whereas the activity values were below controls in castrated animals treated with DHT. In immature female rats treated with PMSG, 5α-reductase activity decreased by 40% to that of anoestrous controls. These results indicate that in the rat adrenal cortex the content of mRNA encoding 5α-reductase is negatively regulated by sex hormones presumably at the transcriptional level. Suppression of the enzymatic activity of adrenal 5α-reductase by sex hormones is due to lower mRNA levels encoding this protein.

Free access

Silvia Ottaviani, Alexander de Giorgio, Victoria Harding, Justin Stebbing and Leandro Castellano

transcriptional output from miRNA loci. Expression profiling studies in prostate cancer have identified an array of androgen up- and down-regulated miRNAs potentially involved in prostate cancer progression ( Porkka et al . 2007 , Ambs et al . 2008 , Ozen et

Free access

Laurent Léotoing, Michèle Manin, Didier Monté, Silvère Baron, Yves Communal, Corinne Lours, Georges Veyssière, Laurent Morel and Claude Beaudoin

-responsive mesenchyme in the prostate can elicit a tissue-specific morphologic development of the epithelium, assessed to be negative for AR expression ( Cunha 1996 ). Altogether, these findings suggest that androgen-induced epithelial cell proliferation in the male

Free access

Felix F Brockschmidt, Markus M Nöthen and Axel M Hillmer

, Lundin et al. (2007) reported the first functional comparison of AR with polyG23 and polyG24 using a prostate-specific antigen promoter-driven reporter gene in COS-1 cells. PolyG23 showed higher transactivating activity than polyG24 at various DHT and

Free access

Valeria Giandomenico, Tao Cui, Lars Grimelius, Kjell Öberg, Giuseppe Pelosi and Apostolos V Tsolakis

human OR51E1. OR51E1 mRNA expression has been detected in normal brain ( Vanti et al . 2003 ) and prostate tissue ( Weigle et al . 2004 ). Furthermore, cancer cells, such as prostate carcinoma cells ( Weigle et al . 2004 , Fuessel et al . 2006

Free access

Xiang Zhang and Shuk-Mei Ho

genes in prostate cancer. Intratumoral testosterone levels were found to be higher in metastases removed from castrated men than in primary prostate cancer from untreated eugonadal men. The ability of the cancer to survive and progress to a higher grade

Free access

R Urbatzka, B Watermann, I Lutz and W Kloas

mammals, as in amphibians, the more potent androgen is DHT unlike in fish, where 11-ketotestosterone is the most potent androgen ( Norris 1997 ). DHT promotes in humans and mammals the development of external genitalia or androgenic tissues like prostate

Free access

Misa Nakamura, Bo Han, Toshihide Nishishita, Yanhua Bai and Kennichi Kakudo

found that CT suppresses constitutive phosphorylation of extracellular signal-regulated kinase (ERK1/2) in DU145 prostate cancer cells ( Segawa et al . 2001 ). However, the precise pathways involved are currently unclear. The purpose of this study was

Free access

Rosalia C M Simmen, Melissa E Heard, Angela M Simmen, Maria Theresa M Montales, Meera Marji, Samantha Scanlon and John Mark P Pabona

disease, namely prostate cancer, is also highly associated with dysfunctions in numerous KLFs including KLF4 ( Wang et al . 2010 ), KLF5 ( Frigo et al . 2009 ), KLF6 ( Narla et al . 2001 ), KLF8 ( He et al . 2013 ), and KLF9 ( Shen et al . 2014

Free access

Sang R Lee, Mi-Young Park, Hyun Yang, Geun-Shik Lee, Beum-Soo An, Bae-kuen Park, Eui-Bae Jeung and Eui-Ju Hong

proliferation and hypertrophy in the prostate, whereas they are only involved in cell hypertrophy in the kidney ( Catterall et al . 1986 ). Although kidneys do not require androgens for normal functions ( Catterall et al . 1986 ), it is possible that androgens