title: Androgen ablation results in differential regulation of transforming growth factor-beta isoforms in rat male accessory sex organs and epididymis.
abstract: The male accessory sex organs and epididymis regress following androgen depletion, although the onset of apoptosis varies temporally depending upon the tissue type. Transforming growth factor-beta1 (TGF-beta1) is an androgen-repressed gene and believed to be an apoptotic agent in the regressing rat ventral prostate (VP). Hence, in order to investigate the status of TGF-beta isoforms following castration in androgen-dependent tissues other than VP, this study was undertaken. Northern blot analysis using total RNA from these tissues of intact animals showed higher levels of TGF-beta1 expression as compared with VP, indicating a function other than that of an apoptotic agent for this isoform. Following orchiectomy, TGF-beta1 was induced in all organs studied and the levels were highest at day 3 following castration in seminal vesicle (SV) and the epididymis and decreased by day 5 despite the absence of androgens. This observation implies that TGF-beta1 might not be a truly androgen-repressed gene in these tissues. TGF-beta2 was up-regulated in VP, SV, caput and corpus epididymis but was undetectable in the dorsolateral prostate and cauda epididymis. On the other hand, TGF-beta3 expression was refractory to the androgen status in corpus epididymis and SV but was up-regulated in the remaining tissues. The castration-induced induction of mRNAs was attenuated after exogenous androgen administration. Most importantly, all the isoforms differed significantly in the time and magnitude of induction following castration, suggesting that a single hormone, testosterone, modulates the expression of TGF-betas in an isoform- and tissue-specific manner.
authors.affiliation: Department of Molecular Reproduction, Indian Institute of Science, Bangalore-560 012, India.
authors.forename: K V
authors.initials: KV
authors.lastname: Desai
authors.forename: P
authors.initials: P
authors.lastname: Kondaiah
mesh_terms: D000728:Androgens / Q000502:physiology*; D000818:Animals; D004822:Epididymis / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009919:Orchiectomy; D011467:Prostate / Q000378:metabolism*; D020033:Protein Isoforms / Q000235:genetics; D051381:Rats; D012669:Seminal Vesicles / Q000378:metabolism*; D013739:Testosterone / Q000494:pharmacology*; D016212:Transforming Growth Factor beta / Q000235:genetics*
chemical_list: D000728:Androgens; D020033:Protein Isoforms; D016212:Transforming Growth Factor beta; D013739:Testosterone