Modulation of renal function after endotoxin (lipopolysaccharide, LPS) challenge in the presence or absence of vasopressors (arginine vasopressin [AVP] and norepinephrine [NE]). Rats (n = 8) were challenged according to the methodology described under Methods section. The bar charts represent analysis (mean ± SD) of A, creatinine clearance (CCr) established by the following formula (UV/P × 1/1440 min); B, urine osmolality; C, fractional sodium excretion (FeNa+) established by the following formula (C Na+/CCr); D, Electrolyte- free-water clearance (CH2O) calculated by the following formula (UV × (1 - [UrNa]) + [UrK]/[Na plasma]). Data are representative of trunk blood and total 18-hr urine from control (saline, white bar), norepinephrine (NE, gray bar), arginine vasopressin (AVP, dark-gray bar), LPS plus saline (black bar), LPS plus NE (horizontal shading gradient bar), and LPS plus AVP (vertical shading gradient bar)-treated rats. The p values are indicative of significant difference(s) vs. control or vs. LPS.