Granin proteins (chromogranin A and secretogranin II C23-3 and C26-3) in the intestine of reptiles.
The occurrence, distribution and the possible cellular co-localizations of chromogranin A (CgA) and of two synthetic secretogranin II-peptides (SgIIC23-3 and SgIIC26-3) with several enteric neuropeptides and serotonin have been investigated immunohistochemically in turtles, lizards and snakes. The distribution of CgA-immunoreactivity was restricted only to the enteroendocrine cells in all the reptiles studied. SgII-immunoreactivity--absent in turtle--revealed nerve cells and fibers, besides enteroendocrine cells in lizard and snake guts. Moreover, the two antisera (C23-3 and C26-3) raised against the different regions of the SgII-molecule yielded distinct distribution patterns of immunoreactivity both in the lizard and snake organs. Small amounts of enteric serotonin cells co-stored CgA or SgIIC23-3 in lizards and snakes and only SgIIC26-3-peptide in snakes. CgA was found co-stored with somatostatin in a few enterocytes of the turtle duodenum. In the same gut segment of lizards and throughout the snake organ, neurotensin and the SgIIC23-3-peptide co-existed in a small number of endocrine cells. The pancreatic polypeptide-containing cells were devoid of immunoreactivity both for CgA and SgII. Bombesin immunopositive cells were absent throughout the intestines of the reptiles investigated. The above findings entirely support the heterogenous distribution of granins in neuroendocrine organs and tissues and also within the same neuroendocrine cell population. They further support the concept of a good conservation of granins during phylogeny.
Trandaburu
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Department of Comparative Endocrinology, Institute of Biology, Bucharest, Romania.
Ali
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Trandaburu
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D000818:Animals; D001839:Bombesin / Q000032:analysis; D053379:Chromogranin A; D002864:Chromogranins / Q000032:analysis*; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000166:cytology*; D007421:Intestine, Small / Q000166:cytology*; D008116:Lizards / Q000033:anatomy & histology; D009197:Myenteric Plexus / Q000166:cytology; D009479:Neuropeptides / Q000032:analysis; D011506:Proteins / Q000032:analysis*; D012104:Reptiles / Q000033:anatomy & histology*; D012701:Serotonin / Q000032:analysis; D012911:Snakes / Q000033:anatomy & histology; D013004:Somatostatin / Q000032:analysis; D014426:Turtles / Q000033:anatomy & histology
D053379:Chromogranin A; D002864:Chromogranins; D009479:Neuropeptides; D011506:Proteins; D012701:Serotonin; D013004:Somatostatin; D001839:Bombesin