Improved control of non-insulin-dependent diabetes mellitus by combined halofenate and chlorpropamide therapy.

Combined halofenate-chlorpropamide was evaluated for the treatment of NIDDM. Four subjects treated with 500 mg/day chlorpropamide were given 500-1000 mg halofenate daily for 48 wk or longer. Fasting plasma glucose fell from 210 +/- 16 (+/- SEM) (11.67 +/- 0.89 mM) to 107 +/- 10 mg/dl (+/- SEM) (5.94 +/- 0.55 mM), P less than 0.005. Twelve additional subjects were entered into a 16-wk double-blind study testing chlorpropamide plus either placebo or halofenate. In the halofenate group, the mean fasting glucose fell from 227 +/- 27 (+/- SEM) (12.61 +/- 1.50 mM) and reached 107 +/- 19 mg/dl (+/- SEM) (5.94 +/- 1.06 mM) during the fourth month, whereas the placebo groups showed a decrease from 242 +/- 22 (+/- SEM) to 208 +/- 29 mg/dl (+/- SEM) (P less than 0.005). In addition, halofenate reduced the height of postprandial glycemic excursions by lowering fasting plasma glucose. When halofenate was used as the only therapy, reduction in fasting plasma glucose was small [179 +/- 12 reduced to 142 +/- 8 mg/dl (+/- SEM); 9.94 +/- 0.67 mM and 7.89 +/- 0.44 mM], P less than 0.05.

Effects of estrogen administration on the lipoproteins and apoproteins of the chicken.

The plasma lipoproteins of estrogen-treated and untreated sexually immature hens have been compared with respect to their concentration in plasma, protein and lipid composition, particle size, and and apoprotein composition. Administration of diethylstilbestrol resulted in a 400-fold rise in the concentration of very low density lipoprotein (VLDL), a 70-fold rise in low density lipoprotein (LDL), and a marked reduction in high density lipoprotein (HDL) protein. It also resulted in the production of LDL and HDL which were enriched in triacylglycerol, while the proportion of cholesterol in all three lipoprotein fractions decreased. In contrast to the lipoproteins from untreated birds, lipoproteins of density less than 1.06 g/ml from estrogen-treated birds were not clearly separable into discrete VLDL and LDL fractions, but appeared to be a single ultracentrifugal class. The apoprotein composition of VLDL and LDL from untreated birds differed from each other; however, the apoprotein patterns of VLDL and LDL from estrogen-treated birds were indistinguishable: both contained a large amount of low molecular weight protein in addition to the high molecular weight component that predominates in the untreated state. The apoprotein composition of HDL was also markedly altered by estrogen administration: the 28,000 mol. wt. protein (apo A-I) decreased in amount from 65% to less than 5% of the total, while a low molecular weight (Mr = 14,000) protein and as yet poorly defined high molecular weight components became predominant. These observations indicate that the hyperlipidemia induced by estrogen administration is accompanied by marked alterations, both qualitative and quantitative, in the plasma lipoproteins.

Increased activity of vitamin K-dependent clotting factors in human hyperlipoproteinaemia - association with cholesterol and triglyceride levels.

Levels of blood coagulation factors, cholesterol and triglyceride were measured in human plasma. Prothrombin was significantly elevated in type IIa hyperlipidaemia; prothrombin and factors VII, IX and X in type IIb; and prothrombin and factors VII and IX in type V. Multiple regression analysis showed significant correlation between the levels of these plasma lipids and the vitamin K-dependent clotting factors (prothrombin, factors VII, IX and X). Higher cholesterol levels were associated with higher levels of prothrombin and factor X while higher triglyceride levels were associated with higher levels of these as well as factors VII and IX. Prothrombin showed a significant cholesterol-triglyceride interaction in that higher cholesterol levels were associated with higher prothrombin levels at all levels of triglyceride, with the most marked effects in subjects with higher triglyceride levels. Higher prothrombin levels were noted in subjects with high or moderately elevated (but not low) cholesterol levels. Ultracentrifugation of plasma in a density of 1.21 showed activity for prothrombin and factors VII and X only in the lipoprotein-free subnatant fraction. Thus, a true increase in clotting factor protein was probably present. The significance of the correlation between levels of vitamin K-dependent clotting factors and plasma lipids remains to be determined.

Potentiation of hypoglycemic effect of chlorpropamide and phenfromin by halofenate.

The potentiation of oral hypoglycemic drugs by the antilipemic agent halofenate is reported. Forty-seven diabetic patients were treated for 48 weeks with halofenate, clofibrate, or placebo. Five patients in the halofenate group were taking phenformin plus either chlorpropamide or tolbutamide. Their average initial fasting plasma glucose was 160 mg./dl. All five patients experienced a slow but but substantial fall in fasting plasma glucose. The mean fasting plasma glucose for the five patients after 80 days of halofenate treatment was 63 mg./dl. As oral treatment for diabetes was reduced, the fasting plasma glucose returned to prehalofenate levels. In this study, we did ont detect an effect of halofenate on the fasting plasma glucose of diabetic patients treated with insulin or on the fasting plasma glucose levels of patients treated with diet alone.

Mechanism of avian estrogen-induced hypertriglyceridemia: evidence for overproduction of triglyceride.

Relying on methods other than the determination of turnover rate of triglyceride from the curve of plasma triglyceride radioactivity after administration of labeled precursor, we have confirmed that the endogenous hypertriglyceridemia induced by estrogenization of the chick is accompanied by increased production of triglyceride. Chicks estrogenized with diethylstilbestrol became grossly hypertriglyceridemic and had elevated levels of plasma free fatty acid. Within 5 min of administration of labeled palmitate, estrogenized hypertriglyceridemic birds converted approximately 10 times more plasma free fatty acid to hepatic triglyceride than did controls. In addition, 2 hr after intraperitoneal injection of [14-C]acetate or [U-14-C]glucose, the specific activity of very low density lipoprotein triglyceride (VLDL-TG) of estrogenized birds reached or exceeded that of the untreated controls, and the rapid enrichment of the vastly expanded plasma VLDL-TG pool with labeled triglyceride further indicated that increased production of triglyceride occurs with estrogenization. Furthermore, [14-C]acetate incorporation into VLDL-TG was calculated to be 1.6 and 6.6% of the injected dose in estrogenized birds compared with 0.1 and 0.2% in untreated birds. Increased production of plasma VLDL-TG was confirmed by a kinetic study of VLDL-TG metabolism, employing reinjected, endogenously prepared [14-C]triglyceride-labeled VLDL. The fractional turnover rate of VLDL-TG in estrogenized hypertriglyceridemic birds was substantially less than that in untreated controls (0.32 plus or minus 0.03 vs 0.71 plus or minus 0.03/hr), but the total turnover rate was nearly 50 times greater (244 plus or minus 52 vs. 5 plus or minus 1 mg/hr).