Fig. 8.

In vivo treatment with lovastatin inhibits calcium signaling induced by insulin on rat hepatocytes and on in vivo intact liver. A and B: graphical representation of the fluorescence increase in the nucleus (blue traces) and cytosol (red traces) of a hepatocyte extracted from a control animal (A) and lovastatin-treated animal (B) stimulated with insulin (300 nM) and vasopressin (100 nM) (control nucleus = 165.3 ± 2.5%; control cytosol = 124 ± 1%; n = 50 cells from 3 animals per condition) (lovastatin nucleus = 102.3 ± 3%; lovastatin cytosol = 124 ± 2.6%; n = 50 cells from 3 animals per condition). C: graph showing the ratio of insulin responsive hepatocytes/vasopressin responsive hepatocytes from control and lovastatin-treated animals. Observe a reduced number of insulin responsive cells on the lovastatin group (control = 1.1 ± 0.3 cells vs. lovastatin = 0.44 ± 0.2 cells; n = 5 individual experiments per group, 50 cells for each group). D: graphical representation of the in vivo fluorescence increase of hepatocytes from the liver of control animals (blue traces) and lovastatin-treated animals (red traces) stimulated with insulin (600 nM) (n = 4 animals per group). E: summary of in vivo calcium studies in the liver induced by insulin (control = 143 ± 3% vs. lovastatin = 111 ± 1%; n = 5 animals per group). F: graph showing the percentage of insulin-responsive cells of control and lovastatin-treated groups. Observe the reduced number of responsive hepatocytes of the liver from lovastatin-treated animals (control = 98 ± 1% vs. lovastatin = 20 ± 4%; n = 5 animals and 5 fields analyzed per group). G: confocal images of livers loaded with Fluo-4/AM (6 µM), stimulated with insulin (600 nM) and imaged in vivo. Images were pseudocolored according to the scale shown at the bottom. Scale bar = 40 µM. Objective lens: ×20. The values indicate the means ± SD. *P < 0.01, difference between groups was statistically significant; ns, not significant. Data were analyzed by one-way ANOVA followed by Bonferroni posttests.