In metabolic alkalosis, which Is true about excretion in urine
Correct Answer: Less ammonia
Description: The NH3 production is greatly increased in metabolic acidosis and negligible in alkalosis. It is also observed that activity of renal glutaminase is enhanced in acidosis. The NH3 mechanism is a valuable device for the conservation of fixed base. Under normal conditions, 30 to 50 mEq of H+ ions are eliminated per day, by combination with NH3 and about 10 to 30 mEq, as titratable acid, i.e. buffered with PO4. Ammonia Mechanism A third mechanism operates in the distal renal tubule cells, for the elimination of H+ ions and the conservation of Na+, by production of NH3 by the renal tubular epithelial cells. Source of NH3 in Distal Tubular Epithelial Cells 1. NH3 is produced by the hydrolysis of Glutamine by the enzyme Glutaminase which is present in these cells. 2. In addition to above, if the cells require NH3 more *NH3 can also be formed from other amino acids by oxidative deamination by L-amino acid oxidase. *NH3 can also be formed from glycine by glycineoxidase. The NH3 thus formed forms NH+4 ions by combining with H+ ions and NH+4 ions can exchange Na+ ion from NaCl. NH+4 ions formation *NH3 can diffuse into the tubular filtrate and there forms NH+4 ions in combination with H+ ions. *NH3 can combine with H+ ions inside the cells and then NH+4 ions come into tubular filtrate. This probably is not the principal mechanism as NH+4 ions are less SECTION FIVE readily permeable to tubular epithelial cells (Fig. 41.4).Ref: M.N. Chatterjea - Textbook of Biochemistry, 7th edition, page no: 716
Category:
Biochemistry
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now