title: Antagonists of growth hormone-releasing hormone (GHRH) reduce prostate size in experimental benign prostatic hyperplasia.
abstract: Growth hormone-releasing hormone (GHRH), a hypothalamic polypeptide, acts as a potent autocrine/paracrine growth factor in many cancers. Benign prostatic hyperplasia (BPH) is a pathologic proliferation of prostatic glandular and stromal tissues; a variety of growth factors and inflammatory processes are inculpated in its pathogenesis. Previously we showed that potent synthetic antagonists of GHRH strongly inhibit the growth of diverse experimental human tumors including prostate cancer by suppressing various tumoral growth factors. The influence of GHRH antagonists on animal models of BPH has not been investigated. We evaluated the effects of the GHRH antagonists JMR-132 given at doses of 40 μg/d, MIA-313 at 20 μg/d, and MIA-459 at 20 μg/d in testosterone-induced BPH in Wistar rats. Reduction of prostate weights was observed after 6 wk of treatment with GHRH antagonists: a 17.8% decrease with JMR-132 treatment; a 17.0% decline with MIA-313 treatment; and a 21.4% reduction with MIA-459 treatment (P < 0.05 for all). We quantified transcript levels of genes related to growth factors, inflammatory cytokines, and signal transduction and identified significant changes in the expression of more than 80 genes (P < 0.05). Significant reductions in protein levels of IL-1β, NF-κβ/p65, and cyclooxygenase-2 (COX-2) also were observed after treatment with a GHRH antagonist. We conclude that GHRH antagonists can lower prostate weight in experimental BPH. This reduction is caused by the direct inhibitory effects of GHRH antagonists exerted through prostatic GHRH receptors. This study sheds light on the mechanism of action of GHRH antagonists in BPH and suggests that GHRH antagonists should be considered for further development as therapy for BPH.
authors.affiliation: Veterans Affairs Medical Center, Miami, FL 33125, USA.
authors.forename: Ferenc G
authors.initials: FG
authors.lastname: Rick
authors.forename: Andrew V
authors.initials: AV
authors.lastname: Schally
authors.forename: Norman L
authors.initials: NL
authors.lastname: Block
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Nadji
authors.forename: Karoly
authors.initials: K
authors.lastname: Szepeshazi
authors.forename: Marta
authors.initials: M
authors.lastname: Zarandi
authors.forename: Irving
authors.initials: I
authors.lastname: Vidaurre
authors.forename: Roberto
authors.initials: R
authors.lastname: Perez
authors.forename: Gabor
authors.initials: G
authors.lastname: Halmos
authors.forename: Luca
authors.initials: L
authors.lastname: Szalontay
mesh_terms: D017398:Alternative Splicing / Q000187:drug effects; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D013007:Growth Hormone-Releasing Hormone / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000150:complications / Q000235:genetics; D018836:Inflammation Mediators / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D053583:Interleukin-1beta / Q000378:metabolism; D008297:Male; D016328:NF-kappa B / Q000378:metabolism; D009929:Organ Size / Q000187:drug effects; D011467:Prostate / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood; D011470:Prostatic Hyperplasia / Q000097:blood / Q000201:enzymology / Q000235:genetics / Q000473:pathology*; D051381:Rats; D011944:Receptors, Androgen / Q000378:metabolism; D018013:Receptors, Neuropeptide / Q000235:genetics / Q000378:metabolism; D018017:Receptors, Pituitary Hormone-Regulating Hormone / Q000235:genetics / Q000378:metabolism; D017337:Sermorelin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: C534070:GHRH(1-29)NH2, PhAcTyr(1)-Arg(2)-P(H)e(4-CL)(6)-Ala(8)-Tyr(Me)(10)-His(11)-Abu(15)-His(20)-Nle(27)-Arg(28)-HLCr(29)-; D018836:Inflammation Mediators; D053583:Interleukin-1beta; D016328:NF-kappa B; D011944:Receptors, Androgen; D018013:Receptors, Neuropeptide; D018017:Receptors, Pituitary Hormone-Regulating Hormone; D007334:Insulin-Like Growth Factor I; D017337:Sermorelin; D013007:Growth Hormone-Releasing Hormone; D051546:Cyclooxygenase 2; D017430:Prostate-Specific Antigen; C048250:somatotropin releasing hormone receptor