Triacylglycerol estimation practical

Tg estimation practical for mbbs, bds, nursing, bmlt

1. ESTIMATION OF TRIACYLGLYCEROL/TRIGLYCERIDE FROM GIVEN SAMPLE Binaya Tamang UCMS- Bhairahawa

2. INTRODUCTION The fats and oils are chemically triacylglycerols. Esters of glycerol with 3 F.A. non-polar in character neutral fats . Synth; In all tissue ( major: adipose tissue, liver) Function. Stored in adipose tissue as fuel reserve. Reserve as essential F.A. Precursors of eicosanoids

3. TRIGLYCERIDES / TRIACYLGLYCEROLS (TGs / TAGs)

4. Properties of TGs Properties Hydrolysis By Lipase into FFA and glycerol Saponification By alkali into glycerol and soaps Rancidity Deterioration of TG to unpleasant taste and ordour Lipid peroxidation Oxidation of lipids in living cells to produce peroxides and free radicals

5. Types of TGs. Simple triacylglycerols contain the same type of fatty acid residue at all the three carbons e.g. Tristearoyl glycerol or tristearin. Mixed triacylglycerols: They contain 2 or 3 different types of fatty acid residues. more common. E.g., 1,3 palmitoyl 2 linolenoyl glycerol. In general, fatty acid attached to C 1 is saturated, that attached to C 2 is unsaturated while that on C 3 can be either .

6. REFERENCE RANGE IN SERUM: Normal: < 150 mg/dl Borderline high: 150 -199 mg/dl High: 200 -499 mg/dl Very high: > 500 mg/dl

7. CLINICAL SIGNIFICANCE HYPERTRIGLYCERIDEMIA Primary : familial/ genetic Secondary: acquired/ medical condition AND drugs

8. Secondary: acquired/ medical condition Obesity Diabetes Mellitus Nephrotic syndrome Hypothyroidism Alcoholism Estrogen administration Various drugs: β blockers, thiazides etc.

9. HYPOTRIGLYCERIDEMIA Large dose of ascorbic acid Drugs: Oral hypoglycemics, heparin etc. Hyperthyroidism Malnutrition Malabsorption Liver failure NOTE: In clinical context, it is hypertriglyceridemia, or rather dyslipidemia, that is more relevant

10. OBESITY High carb. and fat diet leading to increased synthesis. Less utilization related to lifestyle and genetic factors. DIABETES MELLITUS Decreased amount &/or activity of insulin ↓ed LPL activation in vessel ( ↓ed clearance TG rich lipoproteins) ↑ed lipolysis (HSL)in adipose tissue ( ↑ed influx of FFA to liver  hepatic TG ↑es) As a result high TG in blood.

11. Alcoholism Change in redox potential (↑ed NADH/NAD + ratio)  high energy level ↓ed TCA cycle and β oxidation of fatty acid. favors lipogenesis ( acetyl coA to FA synthesis  TG ) High TG fatty liver

12. Nephrotic syndrome Loss of albumin  compensatory increase of lipoprotein by liver (Apo B-100) ↑es VLDL and IDL. Also, in nephrotic patient the Lipoprotein lipase and hepatic lipase activity is ↓ed clearance of TG. Hypothyroidism Decreased LPL activity  low clearance of VLDL in blood. ↑ed TSH  ↑es HSL activity in adipose tissue  more FFA in serum  esterification  ↑ TAG in blood. various other factors (many genes of FA/Chol. synthesis and breakdown are affected).

13. Some clinical signs Arcus senilis Lipemia retinalis Eruptive xanthomas White ring White blood vessel of retina

14. QUANTITATIVE ESTIMATION OF TG (GPO METHOD) PINK/RED Sample: serum/fasting: to reduce effect of chylomicron TAG.

15. B S T Reagent (ml) 1 1 1 Standard ( μ l)(200mg%) - 10 - Sample ( μ l) - - 10 - Incubate at 37 C for 10 min. -After the reaction is complete, measure the absorbance of S and T against reagent blank (B) at 520 nm.