Metabolism
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Overheating after overdosing on E - and slimming by taking dinitrophenol
IET
overdosed on on Ecstasy (MDMA = methylenedioxymethamphetamine) at a rave.
She become hyperthermic, and hyperventilated.
What is happening to increase her rate of oxygen consumption and her body temperature?
The increased rate of oxygen consumption and the increase in body temperature suggest that she is oxidising more metabolic fuel - we have already seen that each litre of oxygen consumed is equivalent to 20 kJ of energy expenditure - and whether this energy expenditure is associated with physical work or not, there will be an increase in heat output from the body.
What we have to consider is how it is possible for MDMA to increase the rate at which metabolic fuels are being oxidised, so leading to excessive heat production, and hence hyperthermia.
What is the main way in which the oxidation of metabolic fuels is controlled?
The aim of oxidising metabolic fuels, and hence the aim of energy yielding metabolism, is to permit the phosphorylation of ADP to ATP, so permitting the various energy requiring processes (ion transport, muscle contraction, protein synthesis and endothermic reactions) to occur. Therefore it would seem obvious that the main controlling factor over the rate at which metabolic fuels are oxidised is the need for ATP. In turn, the need to phosphorylate ADP to ATP is signalled by the availability of ADP to be phosphorylated.
So, the main factor controlling the oxidation of metabolic fuels is the utilisation of ATP in energy requiring processes.
Remember that although the total amount of (ATP = ADP) in the body is only about 5 grams, the total amount of ATP formed from ADP, and the total amount of ATP utilised each day is about equal to body weight, some 70 kg.
How can we measure the rate at which metabolic fuels are being oxidised?