Relationships between apolipoprotein(a) phenotype and increase of lipoprotein(a) by troglitazone

Troglitazone is a new oral hypoglycemic agent that reduces insulin resistan ce in non-insulin-dependent diabetes mellitus (NIDDM). However, this agent increases serum lipoprotein(a) [Lp(a)], which is known as an atherogenic li poprotein. The relationships between the response of Lp(a) to troglitazone and the apolipoprotein(a) [apo(a)I phenotype were investigated in this stud y. Nineteen NIDDM patients were treated with troglitazone for 4 weeks. Lp(a ) increased significantly from 20.1 +/- 16.5 mg/dL to 44.1 +/- 31.9 mg/dL ( P <.001) in all study patients. Lp(a) increased from 25.7 +/- 34.2 mg/dL to 50.1 +/- 38.7 mg/dL (P =.03) in patients with smaller apo(a) phenotypes (S 1S4 to S2S4). Lp(a) also increased from 17.5 +/- 12.0 mg/dL to 41.3 +/- 29. 6 mg/dL (P <.01) in patients with larger apo(a) phenotypes (S3 to S4). Ther efore, the increase of Lp(a) by troglitazone may be independent of the apo( a) phenotype. Copyright (C) 1999 by W.B. Saunders Company.