Epidemiological studies have demonstrated that low birth weight is associated with an increased incidence of
visceral obesity and metabolic disorders in later life. In the present study, we have determined the impact of
birth weight and gender on gene expression in visceral adipose tissue (VAT) in the young adult sheep. Lambs (n=19,
birth weight range 2.6-7.55 kg) were born at term and growth monitored for 22.4+/-0.2 weeks, when body composition was determined by Dual X-ray Absorptiometry (DXA) and samples of VAT and subcutaneous (SCAT) adipose tissue collected. Plasma samples were collected at post-mortem for the determination of
free fatty acids (FFA),
glucose and
insulin concentrations.
Peroxisome-Proliferator Activated Receptor-gamma (
PPARgamma),
glycerol-3-phosphate dehydrogenase (G3PDH),
lipoprotein lipase (LPL),
adiponectin and
leptin mRNA expression was determined by qRT-PCR. Fractional growth rate in postnatal weeks 1-3 was inversely related to
birth weight in both males and females (R2=0.22, P<0.05, n=19).
PPARgamma mRNA expression in VAT, but not SCAT, was inversely related to
birth weight (R2=0.60, P<0.01, n=18). In males, but not females,
PPARgamma mRNA in VAT was directly related to G3PDH
mRNA expression (R2=0.69, P<0.01, n=9). Plasma FFA concentrations were inversely related to
birth weight in both males and females (R2=0.22, P<0.05, n=19). These findings demonstrate that low birth weight is associated with an increased expression of a key adipogenic factor in visceral adipose tissue in young adulthood. In males, this is associated with an increased expression of lipogenic genes, and this may contribute to the increased propensity for
visceral obesity in low birth weight males compared to females.