DR. M. SIVA KUMAR REDDY MD DEPARTMENT OF BIOCHEMISTRY SRI VENKATESWARA MEDICAL COLLEGE

INTRODUCTION Adult body contains about 1 kg phosphate

and it is found in every cell of the body. the human body, it's found in DNA, bones,

and as an ion used for muscle contraction and nerve conduction.

Pure phosphorus can be deadly. White phosphorus, in particular, is associated

with negative health effect. white phosphorus can cause chemical burns.

About 80% occurs in combination with Ca in the bones and teeth.

10% phosphorus found in muscles and blood in association with proteins, carbohydrates and lipid.

10% is widely distributed in various chemical compounds.

 matches were made using white phosphorus. Red phosphorus is a safer alternative and is

considered non-toxic.

INTRODUCTION

PHOSSY JAW(PHOSPHORUS NECROSIS)

BIOCHEMICAL IMPORTANCE Phosphorus is essential for the development of

bones and teeth. Formation and utilization of high-energy phosphate

compounds e.g. ATP, GTP, creatine phosphate. Phosphorus is required for the formation of

phospholipids, phosphoproteins and nucleic acids (DNA and RNA).

Essential component of several nucleotide coenzymes e.g. NAD+, NADP+, pyridoxal phosphate, ADP, AMP.

Several proteins and enzymes are activated by phosphorylation.

Phosphate buffer system is important for the maintenance of pH in the blood and in the cells.

DIETARY REQUIREMENTS RDA of phosphate is based on the intake of calcium.

Ratio of Ca : P of 1: I is recommended (800mg/day).

For infants the ratio is around 2 :1.

majority of natural foods in 1 : 1 ratio.

Brazil nutsgarlic

Cashew nuts mushroomsAlmonds

pumpkinseedsSesame seeds Wheat bran

PHOSPHORUS ABSORPTION

* Calcitriol promotes phosphate uptake along with calcium.

*optimum when the dietary Ca : P is between 1:2and2:1.

*Acidity favours while phytate decreases phosphate uptake by intestinal cells.

SERUM PHOSPHATE phosphate level of the whole blood is around

40 mg/dl. But serum level is t 3-4 mg/dl. RBC and WBC have very high content of

phosphate. Fasting serum phosphate levels are higher

than the postprandial. Ingestion of carbohydrate (glucose), the

phosphate from the serum is drawn by the cells for metabolism (phosphorylation reactions).

SERUM PHOSPHATE

free ions (40%)

10%of phosphate is

bound to proteins

complex form (50%)

Complex form with cations such as Ca2+, Mg2+, Na+, K+

EXCRETION OF PHOSPHORUS *500 mg phosphate is excreted in urine per day *Renal threshold is 2 mg/dl

*Reabsorption of phosphate inhibited by PTH

PHOSPHORUS DISEASED STATES Serum phosphate level is increased in

hypoparathyroidism and decreased in hyperparathyroidism.

ln severe renal diseases ,serum phosphate content is elevated causing acidosis.

Vitamin D deficient rickets is characterized by decreased serum phosphate (1-2 mg/dl).

Renal rickets is associated with low serum phosphate levels and increased alkaline phosphatase activity.

PHOSPHORUS LEVELS IN DIABETICS

*Organic phosphate is lower while that of inorganic phosphate is higher.

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