Mitani F, Miyamoto H, Mukai K, Ishimura Y
Department of Biochemistry, School of Medicine, Keio University, Tokyo, Japan.
Endocr Res. 1996 Nov;22(4):421-31. doi: 10.1080/07435809609043728.
In the rat adrenal cortex, aldosterone synthase cytochrome P450 (P450aldo), a mineralocorticoid synthesizing enzyme, localizes in the zona glomerulosa (zG), while cytochrome P45011 beta (P45011 beta), a glucocorticoid synthesizing enzyme, localizes in the zonae fasciculata-reticularis (zFR). In between zG and zF, a cell-layer which contains neither P450aldo nor P45011 beta is present, where replicating cells were abundant as judged by the incorporation of bromodeoxyuridine (BrdU) and/or by detecting PCNA in their nuclei. When plasma ACTH level of the rat was raised 3-fold for 2-3 weeks by the administration of metyrapone, a potent inhibitor of glucocorticoid formation, most of zG cells containing P450aldo disappeared, while zF cells with P45011 beta increased. Under the conditions, the cell-layer without P450aldo and P45011 beta became very thin, and replicating cells were mainly in the outermost portion of zF. When angiotensin II secretion was also stimulated for 2-3 weeks by feeding the rats on Na-deficient diet, the P450aldo-containing cells proliferated to form a thicker zG (7-8 cells-thick from 1-2), while the width of zF containing P45011 beta decreased slightly. Coincidently the cell-layer devoid of P450aldo and P45011 beta became thin, though slightly, and numbers of replicating cells significantly increased in and around the inner edge of the proliferated zG. When both ACTH and angiotensin II secretions were stimulated simultaneously, the cell-layer without P450aldo and P45011 beta almost disappeared and replicating cells were around the boundary of zG and zF. Based on these results we propose that the cell-layer between zG and zF devoid of P450aldo and P45011 beta is the stem cell layer of rat adrenal cortex.
在大鼠肾上腺皮质中，醛固酮合成酶细胞色素P450（P450aldo）是一种盐皮质激素合成酶，定位于球状带（zG），而细胞色素P45011β（P45011β）是一种糖皮质激素合成酶，定位于束状带-网状带（zFR）。在zG和束状带（zF）之间，存在一个既不含有P450aldo也不含有P45011β的细胞层，通过溴脱氧尿苷（BrdU）掺入和/或检测细胞核中的增殖细胞核抗原（PCNA）判断，该层中复制细胞丰富。当通过给予甲吡酮（一种有效的糖皮质激素形成抑制剂）使大鼠血浆促肾上腺皮质激素（ACTH）水平在2 - 3周内升高3倍时，大多数含有P450aldo的zG细胞消失，而含有P45011β的zF细胞增加。在这种情况下，不含P450aldo和P45011β的细胞层变得非常薄，并且复制细胞主要位于zF的最外层部分。当通过给大鼠喂食缺钠饮食刺激血管紧张素II分泌2 - 3周时，含有P450aldo的细胞增殖形成更厚的zG（从1 - 2个细胞厚增加到7 - 8个细胞厚），而含有P45011β的zF宽度略有减小。巧合的是，不含P450aldo和P45011β的细胞层虽然略有变薄，但增殖的zG内边缘及其周围的复制细胞数量显著增加。当同时刺激ACTH和血管紧张素II分泌时，不含P450aldo和P45011β的细胞层几乎消失，并且复制细胞位于zG和zF的边界周围。基于这些结果，我们提出zG和zF之间不含P450aldo和P45011β的细胞层是大鼠肾上腺皮质的干细胞层。
