Concentration-dependent effects of insulin on Ca2+ influx in vascular smooth muscle cells of normotensive and spontaneously hypertensive rats.
1. The effect of insulin on cytosolic free Ca2+ concentration was measured using fura-2 in vascular smooth muscle cells of normotensive and spontaneously hypertensive rats. 2. In both strains, insulin increased cytosolic free Ca2+ concentration in a concentration range between 10(-6) and 10(-3) units/ml. The maximum increase in cytosolic free Ca2+ concentration was observed with 10(-5) units/ml insulin (107 +/- 25 and 82 +/- 27 nmol/l in spontaneously hypertensive rats and normotensive rats, respectively). 3. The effect of insulin was dependent on extracellular Ca2+ and was enhanced by stimulation of protein kinase C. 4. Thus insulin appears to induce a Ca2+ influx in vascular smooth muscle cells only over a certain range of concentrations. No significant difference in the response to insulin of cells from normotensive and hypertensive rats was observed.
Zhu
Z
Z
Medizinische Universität Poliklinik, Münster, Germany.
Tepel
M
M
Neusser
M
M
Mehring
N
N
Zidek
W
W
D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006973:Hypertension / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009543:Nifedipine / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
D007328:Insulin; D000804:Angiotensin II; D011493:Protein Kinase C; D009543:Nifedipine; D002118:Calcium