Kirschenbaum S R, O'Shea M
Bedford New College, University of London, Egham, Surrey.
Development. 1993 Aug;118(4):1181-90. doi: 10.1242/dev.118.4.1181.
Neuroendocrine glands that synthesize and secrete peptide hormones regulate the levels of these peptide messengers during development. In this article we describe a mechanism for regulating neuropeptide levels in the corpora cardiaca of the locust Schistocerca gregaria, a neuroendocrine gland structurally analogous to the vertebrate adenohypophysis. A set of five colocalized peptide hormones of the adipokinetic hormone family is synthesized in intrinsic neurosecretory cells in the corpora cardiaca. During postembryonic development there are progressive changes in the absolute and relative levels of these five peptide hormones. We show that the ability of the gland to increase peptide synthesis is due to a 100-fold increase in the number of cells which make up the gland. The gland grows by the addition of new cells derived from symmetrical division of undifferentiated precursor cells within the corpora cardiaca. We show, using double-label immunocytochemistry, that cells born in the glandular lobe mature into cells that express adipokinetic hormone peptides. The pattern of cell birth and peptide expression can account for the dramatic increase in postembryonic peptide levels.
合成并分泌肽类激素的神经内分泌腺在发育过程中调节这些肽类信使的水平。在本文中，我们描述了一种调节蝗虫沙漠飞蝗心侧体中神经肽水平的机制，心侧体是一种在结构上类似于脊椎动物腺垂体的神经内分泌腺。一组共定位的五种脂肪动激素家族肽类激素在心侧体的内在神经分泌细胞中合成。在胚胎后期发育过程中，这五种肽类激素的绝对水平和相对水平都有渐进性变化。我们发现，该腺体增加肽合成的能力是由于构成腺体的细胞数量增加了100倍。腺体通过添加源自心侧体内未分化前体细胞对称分裂产生的新细胞而生长。我们使用双标记免疫细胞化学方法表明，在心叶中产生的细胞成熟为表达脂肪动激素肽的细胞。细胞产生和肽表达的模式可以解释胚胎后期肽水平的显著增加。
