Teitelman G, Lee J, Reis D J
Dev Biol. 1987 Apr;120(2):425-33. doi: 10.1016/0012-1606(87)90246-6.
The pancreatic islets of mouse embryos are comprised of four different endocrine cell types and of cells containing a hormone (i.e., glucagon) and a catecholamine enzyme (tyrosine hydroxylase, TH) which appear sequentially during development in vivo. The presence of TH in glucagon cells, however, is transient, since adult pancreatic A cells do not express the enzyme. In this study we sought to determine whether the endocrine precursor cells are primed to differentiate and express catecholamine enzymes during their maturation following a predetermined sequence or whether these processes are regulated by environmental cues. To answer this question, we used immunocytochemical procedures to examine the differentiation of pancreatic rudiments removed from E11 mouse embryos and maintained in culture and of pancreases that regenerated in vitro from E11 pancreatic ducts. We found that although all the endocrine cell types differentiate in the gland in culture, the sequence of their appearance is different from that in vivo, suggesting that the timing of differentiation may be regulated by environmental factors. We also found that, in vitro, the pancreas contains TH-glucagon cells, indicating that the expression of the enzyme by pancreatic A cells is independent of factors present in vivo. Moreover, the fact that the TH-glucagon cells also differentiate during pancreatic regeneration suggests that the expression of the enzyme may be a characteristic stage of endocrine cell precursors during maturation.
小鼠胚胎的胰岛由四种不同的内分泌细胞类型以及含有一种激素（即胰高血糖素）和一种儿茶酚胺酶（酪氨酸羟化酶，TH）的细胞组成，这些细胞在体内发育过程中依次出现。然而，胰高血糖素细胞中TH的存在是短暂的，因为成年胰腺A细胞不表达该酶。在本研究中，我们试图确定内分泌前体细胞在成熟过程中是否按照预定顺序被启动分化并表达儿茶酚胺酶，或者这些过程是否受环境信号调节。为了回答这个问题，我们使用免疫细胞化学方法检查从E11小鼠胚胎中取出并在培养中维持的胰腺原基以及从E11胰管体外再生的胰腺的分化情况。我们发现，虽然所有内分泌细胞类型在培养的腺体中都能分化，但其出现顺序与体内不同，这表明分化的时间可能受环境因素调节。我们还发现，在体外，胰腺含有TH-胰高血糖素细胞，这表明胰腺A细胞中该酶的表达独立于体内存在的因素。此外，TH-胰高血糖素细胞在胰腺再生过程中也会分化，这一事实表明该酶的表达可能是内分泌细胞前体成熟过程中的一个特征阶段。
