ISSN:
0002-9106
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Medicine
Notes:
Splenic islets of Anolis carolinensis incubated in an in vitro perifusion system with media containing a non-stimulatory concentration of glucose had the same ultrastructural appearance as islets removed from an intact animal. When horseradish peroxidase was included in this medium, no profiles suggestive of emiocytotic release of B granules were observed despite basal insulin secretion.With cytochalasin B and a high concentration of glucose, the B cells exhibited margination of their secretory granules and moderate degranulation, but rarely were profiles suggestive of emiocytosis seen. In the presence of cytochalasin B, glucose and the other insulin secretagogues used, the B cells were more degranulated than with only cytochalasin B and glucose present, but profiles indicative of emiocytosis were infrequently encountered. Emiocytosis of the B granules was demostrated convincingly with the inclusion of peroxidase and the above agents. Virtually all the B cells had at least one secretory granule fused with the limiting membrane and surrounded by the peroxidase, and some B cells exhibited multiple release of granules. From these observations it is concluded that emiocytosis plays a major role in the secretion of insulin from B cells of Anolis.The B cells from control perifusions, as well as from intact animals, did not contain a microfilamentous cell web. Granular or filamentous masses were not demonstrated in B cells from splenic islets perifused with cytochalasin B. The mechanism of emiocytotic release of insulin from the B cells of Anolis is discussed with reference to these observations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aja.1001380406
