Differential response of adipose tissue gene and protein expressions to 4‐ and 8‐week administration of β ‐guanidinopropionic acid in mice

β ‐Guanidinopropionic acid ( β ‐ GPA ) feeding inhibits growth‐associated gain of body mass. It remains unknown, however, whether and how β ‐ GPA feeding affects growth‐associated increase in white adipose tissue ( WAT ) mass. We examined the effects of 4‐ and 8‐week β ‐ GPA feeding on serum myostatin levels and expression of genes and proteins related to adipogenesis, lipolysis, and liposynthesis in epididymal WAT ( eWAT ) and brown adipose tissue ( BAT ) in 3‐week‐old, juvenile male mice. Body, eWAT , and muscle weights were significantly lower in β ‐ GPA ‐fed mice than in controls after feeding. Four‐ but not 8‐week‐ β ‐ GPA feeding increased the serum myostatin level. Incubation of C2C12 myotubes with β ‐ GPA (1 mM ) significantly promoted myostatin mRNA expression. The protein expression of peroxisome proliferator‐activated receptor gamma coactivator 1 α ( PGC ‐1 α ) and peroxisome proliferator‐activated receptor α ( PPAR α ) was up‐regulated in GPAF eWAT at week 4, but down‐regulated at week 8. There was no significant difference in the protein expression of adipocyte triglyceride lipase ( ATGL ), hormone‐sensitive lipase ( HSL ), fatty acid synthase ( FAS ), and acetyl‐CoA carboxylase ( ACC ) between groups in eWAT . In BAT , no significant difference was found in the protein expression of PGC ‐1 α , PPAR α , ATGL , and HSL between β ‐ GPA ‐fed and control mice, whereas that of FAS and ACC was significantly lower in β ‐ GPA ‐fed mice at week 8. Uncoupling protein 1 was expressed higher in β ‐ GPA ‐fed mice both at weeks 4 and 8 than that in controls. Thus, the mechanism by which β ‐ GPA feeding in early juvenile mice inhibits growth‐associated increase in eWAT mass may differ between early and later periods of growth.