Question

How might the following substances end up in urine?
Glucose -
Albumin -
Leukocytes -

Answer 1

** Glucose - Normally glucose is present in urine in small quantities ( Less than 150mg/day) . Glucose appears in urine when the blood glucose level increases above 180 mg/dL. The condition is known as Glycosuria (presence of glucose in urine).It may be due to:-

-Diabetes mellitus:- Glycosuria may be the first indicator of diabetes mellitus, because here due to hyperglycemia, glucose in blood crosses renal threshold and is excreted in urine.

- Renal glycosuria:- In this condition, the renal threshold itself is lowered. Thus glycosuria occurs at normal postprandial blood glucose level.

- Nervous glycosuria:- Emotional stressed like anxiety etc causes increased secretion of adrenaline which leads to increased glycogenolysis.This causes hyperglycemia so that renal threshold is exceeded and glycosuria results.

- Endocrine Glycosuria:- Excess secretion of hormones like GH, cortisol and thyroxine raise blood sugar level high enough to cause glycosuria.

** Albumin-  Presence of excess protein (proteinuria) particularly albumin (albuminuria) in urine indicates renal diseases. Urinary excretion of albumin in a normal healthy adult is about 30 mg/day.Proteinuria may be due to:-

- Prerenal proteinuria- occurs in Multiple myeloma a disease producing low molecular weight proteins called Bence Jones proteins.Due to the low molecular weight, they pass through glomerulus and appear in urine.

- Renal proteinuria- Due to renal disease, e.g in Nephrotic Syndrome so negative charges of the filtering membrane are lost.So negatively charged albumin which are normally repelled and prevented from passing now pass freely causing proteinuria.

- Postrenal Proteinuria - occurs as a result of Urinary tract infections.