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Insulin appears in the developing mouse pancreas at embryonic day 12 (e12). Transgenic mice harboring three distinct hybrid genes utilizing insulin gene regulatory information first express the transgene product two days earlier, at e10, in a few cells of the pancreatic bud. Throughout development and postnatal life, all of the insulin-producing (beta)(More)
Neurons containing the enzyme aromatic-L-amino-acid decarboxylase (AADC) but lacking either tyrosine hydroxylase or serotonin were found in the spinal cord of neonatal and adult rats by light and electron microscopic immunocytochemistry. The majority of these neurons localized to area X of Rexed contact ependyma. Thus, spinal AADC neurons have the enzymatic(More)
We sought to determine, in rat embryo, when and at what site in their migration cells derived from the neural crest differentiate into sympathetic neuroblasts. This has been accomplished by immunocytochemical detection, within the cells, of the enzymes catalyzing catecholamine biosynthesis-tyrosine hydroxylase [TH; tyrosine 3-monooxygenase, L-tyrosine,(More)
Pancreatic islets are enveloped by a sheath of Schwann cells, the glial cells of the peripheral nervous system (PNS). The fact that Schwann cells of the PNS become reactive and express nerve growth factor (NGF) and other growth factors following axotomy suggested the possibility that peri-islet Schwann cells could become activated by islet injury. To test(More)
We sought to determine whether the precursors of catecholamine-containing neurons in the developing peripheral and central nervous systems of chickens and rats express the biosynthetic enzymes tyrosine hydroxylase [THase; tyrosine 3-monooxygenase; L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] or dopamine(More)
Three different cases of pancreatic beta cell hyperplasia in mice are accompanied by an increase in a subclass of cells expressing tyrosine hydroxylase (TH), a neuronal enzyme. In the nontumorigenic cases of islet growth during normal pregnancy and in the obese mutant mouse, the TH-insulin cells do not divide, in contrast to the "insulin-only" cells. In(More)
In this study, we sought to determine whether neurons of the chick embryo ciliary ganglia (CG), a parasympathetic cholinergic ganglia, can express catecholaminergic (CA) traits. To accomplish this, we used immunocytochemical techniques to examine the presence of the CA enzymes tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT) in(More)
A population of proliferating cells in the fetal gut has previously been found to express transiently aspects of a catecholaminergic phenotype (TC cells) during development in both rats and mice. These cells appear to be noradrenergic in rats but dopaminergic in mice. In the current study, the ability of TC cells, identified by the immunocytochemical(More)
Previous studies have demonstrated that, in rat, individual sympathetic neurons can express both adrenergic and cholinergic biosynthetic enzymes in culture. Moreover, the levels of these enzymes can be regulated by factors present in their environment. In the present study, we sought to determine whether cultures of chick sympathetic neurons express both(More)
The ability of the adult pancreas to generate new insulin (beta) cells has been controversial because of difficulties in unequivocally identifying the precursor population. We recently determined that beta cells were generated during development from precursors that expressed the homeodomain-containing transcription factor pancreas duodenum homeobox gene-1(More)