Possible modulatory role of non-activated lymphocytes on insulin secretion.
In order to study the probable physiological role of non-activated lymphocytes on islet B-cells, we incubated and perfused rat pancreatic islets in the presence of low (2.8 mM) and high (16.7 mM) glucose concentrations after pre-exposure for 60 min to rat lymphocytes or to substances secreted by lymphocytes. Insulin secretion and 86Rb+, 45Ca2+ and [3H]-phosphoinositide metabolite fluxes were lower compared to controls when islets were pre-exposed to lymphocytes but were not different when islets were pre-exposed to substances secreted by lymphocytes. These alterations in isotope flux suggest that, when lymphocytes and islets are in contact, closure of potassium channels and a paradoxical effect of glucose load on insulin release occur in the presence of low glucose concentrations. The alterations observed are probably due to a swift and direct action of lymphocyte secretion perhaps induced by a direct of islet cells.
Meira
A F
AF
Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Brasil.
Freire
P M
PM
Rocha
M S
MS
Curi
R
R
Zorn
T M
TM
Carpinelli
A R
AR
D000818:Animals; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D007515:Islets of Langerhans; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D051381:Rats
D007328:Insulin