Hype ram monaemia inhib it TCA cycle by depleting: (PGI June 2009)

Ans: B (a-ketoglutarate) ; Harper 29th/168"HyperammonaemiaQ reduce mitochondrial pool ofa-ketoglu tarate & consequently depresses the TCA cycle, affecting the cellular respiration"- Chatterjea & Shinde 7th/447Hyperammonoemia| NH3 concentration enhance amination of a-KGQ, an intermediate in TCA cycle to form glutamate in brain. This reduce a-KG pool in mitochondria.|NH3 concentration enhance "glutamine formation from glutamate & thus reduces 'brain-cell' pool of glutamic acid. Hence there is |ed formation of inhibitory neurotransmitter "GABA" (g-amino butyric acid)Rise in brain glutamine cause increase in tryptophan concentration in brain cells, which leads to abnormal increase in synthesis of "serotonin" a neurotransmitter.Cause mental retardation5'Acquired hyperammonoemia may be due to hepatitis &alcohlasmToxic effects of NH. on the brain are d/t impairment of ATP formationAlso know: Metabolic fate of NH3 in body:Majority of NH3 is converted to urea (urea cycle) Q Formation of glutamine Amination of a-keto add to form a-amino acid