Vascular and insulinotropic effects of YC 170, a calcium agonist, on isolated perfused rat pancreas.

To explore simultaneously the effects on insulin secretion and on vascular tone of YC 170, a new dihydropyridine derivative calcium agonist, isolated perfused rat pancreases were studied for insulin output and for duodenopancreatic resistances before, during and after exposure to YC 170 10(-4) M (n = 15) or its solvent (n = 10). Although insulin was stimulated transiently during the five first minutes following addition of YC 170 (p less than 0.01) the integrated insulin output measured during the whole experiments was not different with YC 170 from that observed with solvent. Conversely, the initial duodenopancreatic resistances (22 +/- 4 mmHg.ml-1.min-1) rose progressively with YC 170 up to maximal values at the end of experiments (104 +/- 28 mmHg.ml-1.min-1; p less than 0.01); no significant variation occurred with solvent. Vascular and insulinotropic effects of YC 170 can be dissociated, suggesting variable abilities to promote calcium transport across membranes of smooth muscle cells and of pancreatic B-cells.