FIG. 1.

Acute hyperglycemia increases cardiac LPL dimerization. Male Wistar rats were made hyperglycemic by injecting 100 mg/kg DZ i.p. Four hours after injection, animals were killed and hearts were removed. Total LPL protein expression was determined using Western blot normalized to GAPDH. Results are the mean ± SE of six animals in each group (A). Ventricles were lysed with 25 mmol/L ammonia buffer, pH 8.2, containing 1% Triton X-100, 0.1% SDS, 10 units/mL heparin, and protease inhibitor. Equal amounts of total protein from control (CON) and DZ heart homogenates were loaded onto a heparin–sepharose column and eluted with increasing concentrations of NaCl (0.25, 0.75, 1.0, and 1.5 mol/L). One milliliter fractions were collected and examined for LPL activity. Before the activity assay, aliquots of each fraction were diluted with equilibration buffer containing BSA to adjust NaCl concentration to 0.25 mol/L and BSA to 1 mg/mL. Elution was repeated with samples from six animals in each group, but only a representative heparin–sepharose chromatography is illustrated (B). Peak LPL activity is presented as mean ± SE from six animals in each group (B, inset). Fractions with LPL activity (1.0 mol/L) were combined and precipitated by TCA before Western blot for LPL was carried out (C). Results are the mean ± SE of six animals in each group. *Significantly different from control, P < 0.05. AU, arbitrary units.