2009A15 Describe the formation, fate and role of lactate in energy production.



·         Introduction

·         Pathway

·         Functions


Intro: lactate


·  3 carbon molecule

·  Conjugate base of lactic acid


·  Daily production 1,500mmol, rate of anaerobic metabolism

·  Normal plasma concentration 0.5-2mmol/L
(up to 16mM in well trained athletes at max effort)

·  Formed in ICF; crosses cell membranes by facilitated diffusion (MCT transporter)


·  In excess causes high anion gap metabolic acidosis

o ↑ Strong ion difference


Formation / pathway:



Facilitates glycolysis

·  Pyruvate -> lactate regenerates NAD+

·  Important if no mitochondria i.e. RBC

·  Important in anaerobic metabolism

Substrate for metabolism

·  Lactate -> oxidative phosphorylation as in the above pathway

·  Will occur in any nucleated cell when O2 supply restored

·  Efficient uptake from plasma into myocardium

Substrate for Cori cycle

·  Re-generate glucose during anaerobic exercise

Substrate for glycogenesis





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