C1QTNF9 and metabolic syndrome: The expression of CTRP9 was significantly increased in adipose tissue isolated from 8-weeks-old ob/ob mice compared to that isolated from age-matched wild-type mice, which was distinct from the 12-weeks-old mice (Wong et al., 2009), indicating that the elevated levels of CTRP9 in these young mice may represent a compensatory response before the occurrence of metabolic syndrome.