par Van Schravendijk, Chris;Kiekens, Rita;Heylen, Valère Louis 
;Pipeleers, Daniel
Référence Biochemical and biophysical research communications, 204, 2, page (490-497)
Publication Publié, 1994-10
;Pipeleers, DanielRéférence Biochemical and biophysical research communications, 204, 2, page (490-497)
Publication Publié, 1994-10
Article révisé par les pairs
| Résumé : | Isolated rat β-cells differ in their individual responsiveness to glucose. The present study examines whether two β-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 β-cells; neither did it correct the differences in glucose-induced insulin release between both subpopulations. These results indicate that rat β-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. © 1994 Academic Press. All rights reserved. |
