La Rosa S, Uccella S, Billo P, Facco C, Sessa F, Capella C
Department of Clinical Biological Sciences, University of Pavia at Varese, Italy.
Virchows Arch. 1999 Jan;434(1):29-36. doi: 10.1007/s004280050301.
Activin A and inhibin A, first isolated from the ovary, are dimeric proteins able to modulate pituitary FSH secretion. Inhibin A is a heterodimer composed of one alpha-subunit and one betaA-subunit (alpha-betaA), while activin A is a homodimer of the betaA-subunit (betaA-betaA). Their identification in several tissues has suggested that they have numerous physiological functions, acting as either paracrine or autocrine factors. The aim of this study was to evaluate the expression of activin A and inhibin A in normal endocrine cells and in 70 endocrine tumours from different sites in the gastro-entero-pancreatic system, using specific monoclonal antibodies directed against the alpha- and betaA-subunits of inhibin/activin. Immunoreactivity for the betaA-subunit, but not for the alpha-subunit, was observed in normal G, EC, and GIP cells of the antrum and duodenum, and in pancreatic A cells. BetaA-subunit expression was observed in G cell and A cell tumours, and in a few insulinomas and ileal EC cell carcinoids. The alpha-subunit was found in rare cells in 7 of the 70 tumours and was colocalized with the betaA-subunit in only 1 tumor. Specific types of endocrine cells from the gut and pancreas appear to produce only activin A, a possible paracrine or autocrine modulator. Activin A is mainly produced by tumours derived from endocrine cells that normally express it.
激活素A和抑制素A最初是从卵巢中分离出来的，是能够调节垂体促卵泡激素分泌的二聚体蛋白。抑制素A是由一个α亚基和一个βA亚基组成的异二聚体（α-βA），而激活素A是βA亚基的同二聚体（βA-βA）。它们在多种组织中的发现表明，它们具有众多生理功能，可作为旁分泌或自分泌因子发挥作用。本研究的目的是使用针对抑制素/激活素α亚基和βA亚基的特异性单克隆抗体，评估激活素A和抑制素A在正常内分泌细胞以及胃肠道胰腺系统不同部位的70例内分泌肿瘤中的表达。在胃窦和十二指肠的正常G细胞、肠嗜铬细胞（EC）和胃肠抑肽（GIP）细胞以及胰腺A细胞中观察到了βA亚基的免疫反应性，但未观察到α亚基的免疫反应性。在G细胞瘤和A细胞瘤以及少数胰岛素瘤和回肠EC细胞类癌中观察到了βA亚基的表达。在70例肿瘤中的7例中，在罕见细胞中发现了α亚基，且仅在1例肿瘤中与βA亚基共定位。来自肠道和胰腺的特定类型内分泌细胞似乎仅产生激活素A，它可能是一种旁分泌或自分泌调节剂。激活素A主要由通常表达它的内分泌细胞来源的肿瘤产生。
