Endometriose: papel da superfamília do fator transformador de crescimento beta / Endometriosis: the role of transforming growth factor β superfamily

A endometriose é uma condição ginecológica, que atinge mulheres em idade reprodutiva e pode ser causa de dor e infertilidade. A patogênese da doença é multifatorial e envolve a perda da capacidade de diferenciação das células endometrióticas, moléculas de adesão celular para adesão do endométrio ao peritônio, neoangiogênese, características do fluido peritoneal e alterações do sistema imune. A superfamília do fator transformador de crescimento β (TGF-β) parece exercer papéis importantes na implantação e manutenção do tecido ectópico na endometriose. Ativinas, inibinas, folistatina, hormônio anti-mülleriano e as proteínas morfogenéticas ósseas são membros da superfamília do TGF-β. Estas moléculas são expressas no endométrio humano e apresentam ações importantes na proliferação celular, diferenciação celular, função imune, regulação da apoptose e remodelamento dos tecidos, apresentando, por conseguinte, um importante papel no ciclo menstrual, decidualização do endométrio e no início da gestação. Este artigo objetiva rever os achados sobre tais proteínas no endométrio e seus possíveis papéis na gênese e fisiopatologia da endometriose

Endometriosis is a gynecological pathological entity typical of women in reproductive age, associated with pelvic pain and infertility. The pathogenesis of the disease is multifactorial and it involves loss of the endometriotic cell differentiation, cell adhesion, neo-angiogenesis, peritoneal fluid characteristics, and changes in the immune system. The transforming growth factor β (TGF-β) superfamily seems to play important roles in the implementation and maintenance of ectopic tissue in endometriosis. Activin, inhibin, follistatin, anti-Mullerian hormone, and bone morphogenetic proteins are members of the superfamily of TGF-β. The TGF-β and family members are expressed by human endometrium and act on cell proliferation, differentiation, immune function, apoptosis and tissue remodeling, playing a role in menstrual cycle, decidualization, and early pregnancy. The aim of this study is to review the findings about these molecules in the endometrium and their possible roles in the genesis and pathophysiology of endometriosis

Inhibin binding sites in bovine pituitary membranes

Membranes derived from bovine pituitary glands free of the neural lobe were used to investigate the presence of binding sites for inhibin, a glycoprotein produced by the ovarian granulosa cells capable of selectively suppressing FSH secretion from the pituitary gland. Optimal concentration of membranes (400 micrograms prot) and 125I-bovine inhibin (2 nM) were incubated in a medium containing 50 mM Tris-HCl pH 7.4, 0.01 M MgCl2 and BSA 0.01 percent in a final assay volume of 200 microliters at 37 degrees C for different time intervals. Non-specific binding was estimated using unlabelled inhibin in excess. The time course of specific 125I-bovine inhibin (2 nM) binding to bovine pituitary membranes is slow with 50 percent binding at approximately 20 min of incubation and reaching equilibrium at 90 min of incubation. The kinetic analysis shows an apparent pseudo first order association rate constant (Kob) equivalent to 4 x 10(-2) min-1. Following equilibrium with the tracer, a large excess of unlabelled inhibin (1.27 microM) was able to displace 84 percent of the specific binding within 120 min of incubation and 50 percent of the binding at approximately 40 min. The analysis under displacing conditions showed an apparent dissociation rate constant (K2) equals to 1.5 x 10(-2) min-1 and an apparent association rate constant (K1) equals to 1.3 x 10(9) M min-1. Thus, the estimation of the apparent kinetic equilibrium dissociation constant (Kd = K2/K2) of the binding of inhibin to bovine pituitary membranes was 1.2 nM. These results show for the first time the existence of bovine inhibin specific binding sites in bovine pituitary, and also that such a binding can take place in the absence of either gonadal and/or hypothalamic influences. They also contribute to the better understanding of the role of non-steroidal hormones such as inhibin, in the regulation of gonadotrophin secretion

Suppression of steroidogenesis in mice granulosa cells by a synthetic nonapeptide fragment of human seminal plasma inhibin.

A synthetic nonapeptide, which is C-terminal sequence of 94-amino acid of prostatic inhibin peptide was tested for progesterone and estrogen secretion by mouse granulosa cell cultures. Nonapeptide suppressed the progesterone and estrogen synthesis, the magnitude of suppression was highest at 5 ng dose level for progesterone and 50 ng dose level for estradiol. The study suggests that, nonapeptide exerts its effect by impairing the binding of FSH to granulosa cell receptors.

Effects of prostatic inhibin and thyroid releasing hormone on lipid peroxidation in rat prostate.

Effects of prostatic inhibin and thyroid releasing hormone (TRH) on lipid peroxidation in rat prostate was studied in an in vitro system. It was found that both inhibited the lipid peroxidase activity thus having a protective role in the prostate.

Does inhibin have intrinsic prolactin suppressing activity?

Evidence to demonstrate suppressive effect of inhibin on prolactin has been presented. The inhibin preparations derived from human testicular tissue, human seminal plasma and porcine follicular fluid were tested and all the three preparations were found to exhibit prolactin suppressing activity.