Fatores hormonais e genéticos na próstata normal e neoplásica

Abstract

Recently, a great deal of attention has focused on the growth regulatory effects of androgens in prostate cells. This has also resulted in much interest in the role of these steroid hormones in the development and maintenance of both normal and neoplastic prostate. However, it has not been possible to identify the exact relationship between androgenic hormone levels and the risk of this disease. The hormone-androgen receptor complex, by association with the DNA androgen response elements, specifically promotes the growth of the prostate gland. It has been recognized that there is a close relationship between the androgen mediated signaling pathway and those promoted by peptide growth factors. More insights are being gained into these complex interactions, some of which may lead to novel therapeutic maneuvers. (Arq Bras Endocrinol Metab 1999;43/3: 177-185).Keywords: Prostate; Prostatic neoplasia; Androgens; Growth factors; Therapy. CONSIDERAÇÕES GERAISA PRÓSTATA É UM ÓRGÃO FIRME, de consistência fibroclástica, que pesa cerca de 20 gramas e apresenta diâmetros máximos de 40 mm. Está localizada na base da bexiga urinaria e, do ponto de vista anatômico, pode ser dividida em lobos laterais, anterior, posterior e mediano. Essa divisão somente é nítida no período embrionário e, no órgão adulto, o limite entre os lobos é impreciso, não existindo septos de tecido conjuntivo que os separem. Histologicamente, apresenta dois tipos glandulares, tubuloacinosas compostas e ramificadas, cuja secreção tem como principal função manter

The prostate of the bat Artibeus lituratus: Seasonal variations, abiotic regulation, and hormonal control

“…Androgen hormones are considered important regulators of the processes of development, maturation, homeostasis, and functioning of the prostate gland (Carvalho‐Salles & Tajara, 1999; Taboga et al, 2009), being essential for the initiation of secretory activity during puberty (Campos, 2014), as well as the maintenance of morphology, functioning, and control of the mechanisms of cell proliferation and death in adults (Marker et al, 2003).…”

“…In the present study, Spearman correlation testing showed that the photoperiod was directly correlated to both temperature and rainfall in the analyzed region. This indicates that all abiotic factors were synergized to provide an increased food supply during the rainy season (fruits), which provides a more favorable environment for reproduction for a fru- -Salles & Tajara, 1999;Taboga et al, 2009), being essential for the initiation of secretory activity during puberty (Campos, 2014), as well as the maintenance of morphology, functioning, and control of the mechanisms of cell proliferation and death in adults (Marker et al, 2003).…”

“…Testosterone (T) is the main androgen that regulates the prostate, but its hydroxylated form, dihydrotestosterone (DHT), presents the greatest performance in the prostate for having greater affinity for androgen receptors (Carvalho-Salles & Tajara, 1999;Taboga et al, 2009). Testosterone production occurs mainly in the testes, but its conversion into DHT, which is catalyzed by 5α-reductase enzyme, occurs mainly in the cytoplasm of prostatic epithelial cells (Sanchez et al, 2013).…”

Efeitos do fitoterápico Tribulus terrestris sobre a próstata do gerbilo da Mongólia (Meriones unguiculatus)

“…Além disso, esse hormônio também é produzido pelas suprarrenais que, sob influência do hormônio adrenocorticotrófico (ACTH) liberado pela hipófise, são induzidas a secretar androstenediona, que é convertida em testosterona perifericamente. Assim que é liberada no sangue, a testosterona se a liga proteínas, com uma pequena quantidade permanecendo livre (CARVALHO-SALLES & TAJARA, 1999;TABOGA et al, 2009). A testosterona livre e, portanto, ativa, adentra a célula prostática através de difusão simples pela membrana até chegar ao citoplasma, onde é convertida pela enzima 5-alfarredutase em dihidrotestosterona (DHT).…”

“…Além dos andrógenos, outros fatores também podem atuar na morfologia e fisiologia da próstata, como os estrógenos, o hormônio do crescimento, a prolactina, a insulina e fatores produzidos pelas próprias células prostáticas, os quais participam de processos autócrinos, parácrinos ou intrácrinos (CARVALHO-SALLES & TAJARA, 1999). Dessa forma, pode-se afirmar que a próstata é influenciada por fatores extrínsecos (orgânicos, hormonais, alimentares, imunológicos etc.)…”