Based on our studies showing an interaction between Lp(a) and ApoB-containing lipoproteins (ApoB-Lp) and the observation that the interacting ApoB-Lp were somewhat enriched in triglyceride (TG), we have initiated studies to explore this potential relationship of Lp(a) and TG-rich lipoproteins. In exploring Lp(a)'s incidence in hypertriglyceridemic subjects, we found a significantly reduced incidence (31%, p less than 0.05) of Lp(a) levels greater than 9 mg/ml when compared to both normolipidemic (61%) and subjects with coronary heart disease (49%). Analyses of a second group of hypertriglyceridemic subjects (n = 68) demonstrated that only 15% of subjects with TG greater than 400 mg/dl (n = 20) had levels of Lp(a) greater than 9 mg/dl while 52% of those with TG levels less than 400 mg/dl (n = 48) had this level of detectable Lp(a). These studies point to an inverse relationship between plasma TG and Lp(a) levels.