Molecular and cellular analysis of pituitary cel differentiation and proliferation.

本研究旨在阐明大鼠垂体生长激素细胞(GH细胞)和乳腺炎细胞(PRL细胞)的分化、增殖和发育(终末分化)。本研究的研究结果如下。(1)免疫组织化学检测GH细胞在胎龄18天，催乳素细胞在胎龄19天。对同时产生生长激素和催乳素的乳头瘤细胞(MS细胞)进行了出生后免疫电子显微镜观察，但数量较少。MS细胞被认为是GH细胞和PRL细胞的前体细胞，或介于Botti Gil细胞和PRL细胞之间的过渡细胞。(2)免疫电子显微镜观察GIL细胞和PRL细胞形态异质性。根据分泌颗粒的大小和细胞的形态，将GH细胞和PRL细胞分为三个亚型。各亚型的相对比例随…而变化更高的年龄和几种激素治疗。这些变化与每种细胞类型的分泌活动的变化密切相关。(3)反向溶血空斑实验显示GH细胞功能异质性。生长激素细胞分为高分泌活性细胞和低分泌活性细胞两个亚群。(4)观察链脲佐菌素诱导的糖尿病大鼠垂体细胞增殖情况。糖尿病大鼠垂体DNA合成细胞的相对比例低于对照组。糖尿病大鼠垂体细胞对雌激素刺激的细胞增殖反应也低于对照组。因此，垂体细胞的增殖可能依赖于胰岛素水平。(5)研究GH和PRL基因表达的增龄性变化。随着年龄的增长，GIL和PRL细胞在转录水平的GH和PRL合成减少。因此，本研究阐明了从胎龄到老年大鼠生长激素细胞和催乳素细胞的形态和功能变化。较少

The present study was aimed to clarify differentiation, proliferation and development(terminal diffelentiation)of somatotroplis(GH cells)and mammotroptis(PRL cells)of the rat pituitary. The findings obtained in the present study are as follows. (1)GH cells were immunohistochemically detected at 18 days of fetal age, and PRL eells were at 19 days of fetal age. Mammosomato trophs(MS cells), which produced both GH and PRL at the same time, were immunoeIectron microscopicaIIy observed during the postnatal period, although the number of them were quite few. MS cells are considered to be the progenitor cells of both GH cells and PRL cells, or the transitional cells between botti Gil cells and PRL cells. (2)Immunoelectron microscopical study snowed morphological heterogeneity of Gil cells and PRL cells. GH cells and PRL cells were sub-divided into three subtypes, respectively on the basis of the size of secretory granules and the cell shape. The relative proportion of each subtype changed wit … More h age and by several hormonal treatments. These changes are closely correlated with changes in the secretory activities of each cell type. (3)Reverse hemolytic plaque assay snowed functional heterogeneity of GH cells. there were two subpopulations in GH cells : high secretory activity cell and low secretory activity cell. (4)The proliferation of pituitary cells were studied in streptozotocin-induced diabetes rats. The relative proportion of DNA-synthesizing pituitary cells was lower in the diabetic rats than in control rats. Also, response of pituitary cells in the diabetic rats to estrogen on the cell proliferation was low as compared with control rats. Thus, the proliferation of pituitary cells may depend on the insulin level. (5)Age-related changes in GH and PRL mRNA levels were studied. The GH and PRL syntheses at the transcription level decreased in each Gil and PRL cell with aging. Thus, the present study clarified morphological and functional changes in GH cells and PRL cells of rats from the fetal ages to senile ones. Less