(A) Daily water intake in C57BL/6J mice administered either vehicle or FGF21 (1 mg/kg/day) by osmotic minipump (n = 5/group). This study was repeated independently five times with similar results.
(B) Urine output over a 24 hour period in groups of mice administered FGF21 or vehicle by osmotic minipump with either ad libitum access to water (Control) or water deprivation (WD) (n = 5/group).
(C–E) Urine osmolality and urine osmoles (C), plasma osmolality (n = 7/group) (D), and electrolytes, creatinine (Cr) and blood urea nitrogen (BUN) (E) in C57BL/6J mice administered FGF21 or vehicle by osmotic minipump (n = 6/group).
(F–H) Plasma copeptin (F) and aldosterone (G) levels, and renin activity (H) in C57BL/6J mice administered either vehicle or FGF21 by osmotic minipump (n = 8/group). Data from groups of 24-hour water-deprived (WD) mice are included as positive controls. This study was repeated independently twice with similar results.
For (A–H), values are means ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001 by Student’s t-test. (I, J) Licking behavior in C57BL/6J mice after a single i.p. injection of FGF21 (1 mg/kg) or vehicle (n = 18/group). Plotted results represent the mean of 6 independent experiments using 3 mice per group (shown in Fig. S1B). The mean number of cumulative licks in the FGF21 group (838.7 licks/hour) was significantly higher than in the control group (670.0 licks/hour) (p = 0.0026) (I). In (J), differences in cumulative licks between the FGF21 and vehicle group (dots) were fitted to a two-piece linear regression model (red line) of the data in (I). The break point for the statistical difference between FGF21 and vehicle treatment was detected at 1.52 hour with 95% confidence interval [0.82–2.81] shown in grey. (K) Cumulative water consumption in C57BL/6J mice after a single i.p. injection of FGF21 (1 mg/kg) or vehicle (n = 9/group).
See also Figure S1.