Apolipoprotein A5 (ApoA5) is fast gaining attention as a key regulator of serum triglyceride concentrations. An ApoA5 mouse knock-out model produced an approximately four fold increase in serum triglyc erides, whereas a knock-in model with human ApoA5 produced 50-70% lower concentrations of mouse serum triglycerides. In addition, peroxisome proliferator-activated receptor-_ agonists, which are used clinically to lower serum triglyceride concentrations, cause increased ApoA5 mRNA expression. Recently, it was demonstrated that ApoA5 is present in human serum detected by polyclonal antibodies against both the NH2 and COOH termini, although at much lower concentration than other apolipoproteins.
