Fig. 1.

Physiological analyses of lithium-induced polyuria over 12 wk of lithium treatment. Male rats were fed a 40 mmol/kg lithium diet for 0, 1, 2, 3, 6, 9, or 12 wk. Single animals were subsequently placed in individual metabolic cages to collect urine and serum at the determined time point. A: serum lithium levels were measured using an EasyLyte according to the manufacturer’s instructions. B: urine was collected over 24 h under oil to prevent evaporation. C: urine osmolality was measured from collected urine. Data are presented as means ± SE, where *P < 0.05 vs. control. Control, n = 11; 1 wk, n = 7; 2 wk, n = 6; 3 wk, n = 8; 6 wk, n = 10; 9 wk, n = 3; 12 wk, n = 3.