Albumin Urinary (S-type) Rat Assay

Research topic

Renal disease, Animal studies

Summary

Albumin is mostly a simple hydrophilic protein present in cells and body fluids. Albumin is synthesized in the liver, and serum albumin (69 kDa, pI 4.9) occupies 56-60% of total serum proteins. Because of its large population, albumin is very important in maintaining plasma osmotic pressure. Albumin can bind hydrophobic physiological substances e.g. fatty acids, bilirubin, and thyroxine and contributes the transfer of these substances. Concentration of albumin in serum is lowered in liver cirrhosis, malnutrition, and pyrexial diseases due to decreased biosynthesis or increased consumption of albumin in, and also by secretion into urine in renal damage. In normal human subjects, excretion of albumin into urine is very little, about 30mg/day, but increased in glomerulonephritis, nephritic syndrome, and diabetic nephropathy. Urinary albumin sometimes increases in pyrexia, hypertension, congestive heart failure (CHF), and urinary tract infection (UTI). Even in healthy human, a transient upraise of urinary albumin is observed after hard exercise, muscle work, bathing in high temperature water, mental excitement, stress, intake of much protein, and before menstruation. These are called physiological or functional or sports proteinuria (albuminuria). Orthostatic proteinuria (albuminuria) is observed in teenagers. Rare hereditary analbuminemia in human is really albumin deficiency. A model analbuminemia rat has been established by Dr. Sumi Nagase which has been derived from Sprague-Dawley strain, and is called Nagase analbuminemia rat (NAR). Routine measurement of serum albumin is conveniently made with Shibayagi’s TIA assay kit for automatic analyzers. Shibayagi’s Albumin ELISA Kit can measure urinary albumin with high sensitivity, and is also applied to in vitro albumin biosynthesis system, checking of contamination with albumin in biological active substance preparations obtained by culture system, and liver transplantation experiments using NAR.