Morphologic and physiologic studies of canine ileal enteroglucagon-containing cells in short-term culture.
Enteroglucagon-containing cells have been maintained in short-term culture, and the morphologic characteristics of these cells and their response to selected agents have been determined. After 48 h in culture the ultrastructural appearance of the enteroglucagon-immunoreactive cells showed evidence of polarization with re-formation of apical microvilli and the secretory granules concentrated at the opposite pole of the cell. The size of the intracellular secretory granules was 370 +/- 15 nm. The release of enteroglucagonlike immunoreactivity was stimulated in a dose-dependent manner by the adrenergic agonists epinephrine and isoproterenol. The response to epinephrine was competitively inhibited by propranolol, producing a rightward shift of the dose-responsive curve. The alpha-adrenergic agonists methoxamine and clonidine did not stimulate enteroglucagon release above basal. The adenyl cyclase activator forskolin also stimulated release of the peptide in a dose-dependent manner. Carbachol and somatostatin produced a dose-dependent inhibition of epinephrine-stimulated release, indicating direct inhibitory modulation of enteroglucagonlike immunoreactive cells. Somatostatin also inhibited forskolin-stimulated release. These data indicate that canine ileal enteroglucagon cells in short-term culture respond to a number of specific stimuli.
D000818:Animals; D002469:Cell Separation; D002478:Cells, Cultured; D002850:Chromatography, Gel; D005576:Colforsin / Q000037:antagonists & inhibitors / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000378:metabolism; D004285:Dogs; D004837:Epinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D005768:Gastrointestinal Hormones / Q000378:metabolism*; D004763:Glucagon-Like Peptides / Q000378:metabolism*; D006651:Histocytochemistry; D007082:Ileum / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D007158:Immunologic Techniques; D013004:Somatostatin / Q000494:pharmacology
D005768:Gastrointestinal Hormones; D005576:Colforsin; D013004:Somatostatin; D004763:Glucagon-Like Peptides; D004837:Epinephrine