Nicotinic acid ?
Ans. is 'a' i.e., Increases HDL Nicotinic acid (Niacin) There arc three main type of lipases related to metabolism of lipoproteins ? Lipoprotein lipase - Present in blood vessels and causes hydrolysis of tryglyceride content of VLDL and chylomicrones. Hepatic lipase - Conves IDL to LDL by hydrolysing the triglyceride content of IDL. Hormone sensitive lipase - Present intracellularly in peripheral tissue and causes intracellular lipolysis by hydrolysing triglycerides. Niacin (Nicotinic acid) inhibits intracellular lipolysis by inhibiting hormone sensitive lipase - intracellular FFA to liver - 4 .1, triglyceride synthesis. Niacin also increases the activity of lipoprotein lipase - T hydrolysis of VLDL triglyceride. Nicotinic acid also reduces the production of VLDL in liver by inhibiting TG-synthesis - indirectly the VLDL degradation products IDL and LDL are also reduced. Nicotinic acid is the most effective drug to raise HDL-CH. Increased HDL is due to interference of direct pathway of HDL cholesterol to liver which involves apo-Ai - Niacin decreases apo- A, mediated hepatic clearance. Nicotinic acid is used in type I, III, IV & V hyperlipoproteinemias.
Increases HDL
Increased triglyceride synthesis
Type II hyperlipoproteinemia
Decreased hydrolysis of VLDL