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Amino-acid responsiveness in beta cell subpopulations with different sensitivity to glucose.
      

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Title: Amino-acid responsiveness in beta cell subpopulations with different sensitivity to glucose.
Author: Van Schravendijk, C F : Kiekens, R : Heylen, L : Pipeleers, D G
Citation: Biochem-Biophys-Res-Commun. 1994 Oct 28; 204(2): 490-7
Abstract: Isolated rat beta-cells differ in their individual responsiveness to glucose. The present study examines whether two beta-cell subpopulations with different thresholds for glucose stimulation also differ in their responsiveness to amino acids that are known to stimulate insulin release. The subpopulations were separated by autofluorescence-activated cell sorting using their metabolic responsiveness to 7.5 mM glucose as discriminating parameter. The 7.5 mM glucose responsive and unresponsive subpopulations were perifused in parallel in order to compare their secretory responses to leucine (10 mM) or to arginine (5 mM); responses to glucose were taken as control. Under maximal glucose stimulation (20 mM), the responsive subpopulation released two-fold more insulin than the unresponsive one whereas maximal stimulation with leucine (10 mM) elicited similar first and second phase responses in the two subpopulations. On the other hand, a maximal arginine stimulus (5 mM) amplified release only from glucose-activated beta-cells; neither did it correct the differences in glucose-induced insulin release between both subpopulations. These results indicate that rat beta-cells exhibit a heterogeneity in secretory responsiveness to glucose but not to leucine, a metabolized secretagogue which can induce release in the absence of glucose. A heterogeneity is also observed in the cellular responsiveness to arginine, and its secretory effect consists of an amplification of glucose-activated cells.
Review References: None
Notes: Copyright Academic Press. Abstracts are reprinted by the permission of the publisher of the journal for volume, pages, and dates cited. Hypertext links to electronic journal sites, if available, can be found in the the Peer Reviewed Journal List on the IBIDS home page.
Language: English
Publication Type: Journal-Article
Keywords: Amino Acids pharmacology : Glucose pharmacology : Islets of Langerhans drug effects
URL: http://www.apnet.com/www/journal/rc.htm