The effect of diazoxide-induced hormonal secretion on plasma triglyceride concentration in the rat

The relationship between non-esterified fatty acid (NEFA) mobilization and hepatic conversion to plasma triglycerides (TG), as modulated by diazoxide-induced effects upon endogenous catecholamine, glucagon, and insulin secretion, was examined in vivo in the rat. Thyrotropin (TSH)-induced NEFA mobilization provided the control study.--In all control experiments, TSH (1.5 IU/100 g) induced a 110% increase in NEFA availability, which was associated with a subsequent 52% increase in plasma TG concentration and a 73% increase in plasma ketone bodies. Following diazoxide administration (30 mg/kg), endogenous secretion of both catecholamines and glucagon was observed, resulting in a comparable 100% increase in NEFA availability, with the appropriate ketonaemic response. However, in contrast to the control TSH study, plasma triglyceride concentration did not increase. This suppression was secondary, at least in part, to a direct 40% inhibition of hepatic secretion of triglycerides.--Although plasma NEFA concentration is an important determinant of plasma triglyceride levels, the concurrent concentration of endogenous catecholamines, glucagon, and insulin modulate the hepatic conversion of NEFA to triglycerides in vivo.