Question

A recent study showed that a newly discovered drug that acts as an uncoupling agent of the electron transport chain was causing significant weight loss in humans.

(i) Describe how uncoupling agents work?

(ii) Based on your knowledge of metabolic processes explain the mechanisms through which this newly discovered drug could be causing weight loss? What might be a side effect of this drug?

Answer 1

Answer: -

1.how uncoupling agent work?

A.Uncoupling agent decreases the formation of high-energy phosphate bonds in mitochondria and at the same time stimulates systemic oxygen consumption .

**This dissociative effect is known as uncoupling of oxidative phosphorylation.

**Adenosine triphosphate (ATP) production is the final product of the tricarboxylic acid (Krebs) cycle in mitocondria along with CO2 and H2O.

*During glycolysis, there is a net production of two ATP molecules, but the majority of energy-rich phosphate bonds (38 in total) are produced during the final oxidative phosphorylation process.

**During this final phase, ATP synthetase converts adenosinediphosphate to ATP with the addition of an inorganic phosphate molecule.

**uncoupling agent interferes with the final energy production pathway by preventing the uptake of inorganic phosphate molecules into the mitochondria .

**This results in the inhibition of all energy-requiring processes and the extra-mitochondrial accumulation of inorganic phosphate .

2.mechanism causing weight loss: -

**uncoupling agent acts as a protonophore, allowing protons to leak across the inner mitochondrial membrane and thus bypass ATP synthase.

**This makes ATP energy production less efficient. In effect, part of the energy that is normally produced from cellular respiration is wasted as heat.

**The inefficiency is proportional to the dose of uncoupling agent that is taken.

**As the dose increases and energy production is made more inefficient, metabolic rate increases and more fat is burned in order to compensate for the inefficiency and to meet energy demands. In this way body weight is lost.

3.side effects of drug:-

A.the classic symptom complex associated with toxicity of uncoupling agent is a combination of

hyperthermia,

tachycardia,

diaphoresis and tachypnoea,

eventually leading to death.