Nicotinic acid, derivatives, actions inhibition

Nicotinic acid derivatives - A new type of diuretic molecule, triflocin, promotes the excretion of as much as 30% of filtered sodium in the dog at high doses and, therefore, approaches furosemide and ethacrynic acid in maximum efficacy24, as with the latter drugs, sodium reabsorption was inhibited in the ascending limb of Henle s loop in animals and man but there was little effect at more distal tubular sites24,25. Thus, K+ and excretion increased and urinary acidity was enhanced. Glucose metabolism was not markedly altered. Synthesized derivatives all were of less interest than the parent molecule. 6-Aminonlcotlnamlde also enhances sodium excretion in the rat, apparently by an action on the distal tubule . 

Nicotinic acid exerts a variety of effects on lipoprotein metabolism (7,16,49). One of its most important actions is the inhibition of lipolysis in adipose tissue. This initial inhibition, like those of previously discussed antihyperlipidemic agents, produces a sequence of events that ultimately result in the lowering of plasma triglycerides and cholesterol. Impaired lipolysis decreases the mobilization of free fatty acids, thus reducing their plasma levels and their delivery to the liver. In turn, this decreases hepatic triglyceride synthesis and results in a decreased production of VLDL. Enhanced clearance of VLDL through stimulation of lipoprotein lipase also has been proposed to contribute to the reduction of plasma VLDL levels. Because LDL is derived from VLDL (Fig. 30.5), the decreased production of VLDL ultimately leads to a decrease in LDL levels. The sequential nature of this process has been clinically demonstrated. The reduction in triglyceride levels occurs within several hours after ... 

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