The relation between the PST1 restriction fragment length polymorphism at the APO-AI locus and plasma APO-AI concentrations in marathon runners.

A PST1 restriction fragment length polymorphism (RFLP), located close to the apolipoprotein AI (apo-AI) gene on chromosome 11, is associated with elevated levels of apo-AI in normal healthy individuals and with depressed levels in patients with coronary heart disease. In both cases the association is with the P2 allele (the allele not containing the PST1 cutting site). Prolonged exercise is known to increase steady-state plasma apo-AI concentrations. We investigated the effect of adaptation to endurance exercise on the association of the PST1 marker with plasma apo-AI levels. Eighty-two male subjects between the ages of 20 and 50 years were randomly selected from a group of local marathon runners. The frequency of the P2 allele was 14% in this group. This was similar to the frequency reported for this RFLP in other population groups of healthy men. Plasma levels of apo-AI were elevated in the marathon runners compared with randomly selected healthy South African men in the same age group. There was, however, no association between the PST1 RFLP and the plasma high-density lipoprotein cholesterol and/or apo-AI concentrations in this group. The elevated apo-AI levels in marathon runners therefore bear no relation to differences associated with the PST1 RFLP at the apo-AI gene locus.