Repeated glucose stimulation reveals distinct and lasting secretion patterns of individual rat pancreatic B cells.
To determine whether pancreatic B cells show a constant secretion pattern during repeated stimulations, we have used a sequential hemolytic plaque assay to monitor their individual insulin release during several successive 30-min incubations in the presence of 16.7 mM glucose. We have found that the total B cell secretion did not vary significantly in these successive glucose stimulations and that, under these conditions, the majority of B cells that were stimulated to release insulin during the first incubation also secreted during the second, third, and, when this was tested, during the fourth incubation. Similarly, most of the B cells that did not release detectable amounts of insulin during the first incubation did not secrete also during the two (or three) subsequent secretion tests. Together, the two groups of B cells that showed a constant secretory pattern, represented approximately 75% of the entire B cell population. The remaining 25% of B cells shifted from a secreting to a non-secreting state, or vice versa, from one incubation to another. These observations were made under three different time frames in which we tested single B cells as well as B cell clusters at rather different intervals. These findings support the existence of distinct B cell subpopulations differing lastingly in their ability to secrete insulin in response to glucose.
Giordano
E
E
Department of Morphology, University of Geneva Medical School, Switzerland.
Bosco
D
D
Cirulli
V
V
Meda
P
P
D000818:Animals; D002449:Cell Aggregation; D004334:Drug Administration Schedule; D005947:Glucose / Q000008:administration & dosage*; D006462:Hemolytic Plaque Technique; D066298:In Vitro Techniques; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012636:Secretory Rate / Q000187:drug effects
D007328:Insulin; D005947:Glucose