Sucrose preference test. The preference for 1% sucrose solution consumption by female (A) or male (B) CD38+/+ (WT) and CD38−/− mice 30 min after treatment with PBS or OT (single i.p. injection). One-way ANOVA was performed and revealed no significance for A (F3,40 = 0.559, p = 0.645) but significance for B (F3,30 = 12.91, p = 0.0001). ** p < 0.01 from CD38−/− with PBS. Sucrose preference in males treated by PBS, OT, or the LOTs 30 min (C) or 24 h after injection (D). A one-way ANOVA followed by Bonferroni’s test revealed significance at 30 min after injection (F5,33 = 8.293, p = 0.0001) and 24 h after injection (F5,31 = 12.40, p = 0.0001). * indicates p < 0.05, ** indicates p < 0.01, compared with CD38−/− male mice treated with PBS.