FIGURE 8.

Water repulsion and thermoregulation are defective in Fatp4^−/−;Tg(IVL-Fatp4) mice. Four control and five Fatp4^−/−;Tg(IVL-Fatp4) mice swam in water at 37 °C for 4 min. Their body weights and rectal temperatures were measured before (time point 0) and at different time points after the 4-min water immersion. A, at 5 min after water immersion, Fatp4^−/−;Tg(IVL-Fatp4) mice appeared much wetter than controls. At 15 min after water immersion, control mice were nearly dry, whereas Fatp4^−/−;Tg(IVL-Fatp4) mice were still wet. B, Fatp4^−/−;Tg(IVL-Fatp4) mice (mutants) showed a statistically significant increase in water retention up to 25 min after water immersion. C, the body temperature of Fatp4^−/−;Tg(IVL-Fatp4) mice (mutants) dropped maximally by 6.4 °C at 15 min, and remained at a low temperature until 30 min after water immersion. In contrast, controls exhibited a maximal reduction of 1.5 °C at 5 min and returned to the pre-swim temperature at 15 min after immersion. Standard deviation and statistical significance (*, p < 0.05; **, p < 0.01; ***, p < 0.001) are indicated in B and C.