Abundance of Circulating Preadipocyte Factor 1 in Early Life

OBJECTIVE: Soluble preadipocyte factor 1 (Pref-1) inhibits adipocyte differentiation. We tested whether circulating levels of soluble Pref-1 are higher in smaller fetuses. RESEARCH DESIGN AND METHODS: We performed longitudinal assessments of circulating Pref-1 in infants born appropriate for gestational age (AGA) or small for gestational age (SGA) and also in late-gestational women and in newborns on days 2 and 3. RESULTS: At birth, Pref-1 levels were approximately 100-fold higher than in adults, being in SGA fetuses approximately 50% higher than in AGA fetuses. By age 4 months, Pref-1 had reached near-adult levels and the original AGA versus SGA difference had disappeared. Pref-1 levels were low in late-gestational women and were still elevated in newborns. CONCLUSIONS: Pref-1 is abundantly present in the fetus, is higher in SGA than in AGA fetuses, and is likely to be of fetal origin. We speculate that Pref-1 in early life contributes to variation in postnatal adipocyte numbers, in the subsequent expandability of adipose tissue, and thus in the susceptibility to diabetes in later life.