Effect of L-NMMA on albumin excretion rate. A) Mean albumin excretion rate in placebo (closed circles) and paricalcitol (open circles) at baseline (average for 3 periods of 30 minutes) and during nitric oxide synthase inhibition (NOSi). B) Mean changes in albumin excretion rate ± SEM at baseline and during NOSi. L-NMMA was continuously infused for 60 minutes. Within differences in each group were tested by Friedman’s two-way ANOVA, and comparisons between placebo and paricalcitol were made for each point in time by Wilcoxon’s signed rank test (*p < 0.05, **p < 0.005) (n = 21).