TABLE 2

Baseline measures of quadriceps mitochondrial content and function for the healthy older (HO), healthy young (HY) and chronic obstructive pulmonary disease (COPD) groups

	HO (n=10)	HY (n=10)	COPD (n=20)	p-value three-way ANOVA	*p-value HO versus* HY**	*p-value HO versus* COPD**
Citrate synthase activity, mmol acetyl-CoA·min⁻¹·L mitochondrial suspension⁻¹	0.512±0.132	0.520±0.146	0.397±0.172	0.070
MAPR (glutamate and succinate), μmol ATP·mmol⁻¹ acetyl-CoA·min⁻¹	1235±193	1249±142	1148±147	0.884
MAPR (glutamate and malate), μmol ATP·mmol⁻¹ acetyl-CoA·min⁻¹	975±340	963±355	806±277	0.269
MAPR (pyruvate and malate), μmol ATP·mmol⁻¹ acetyl-CoA·min⁻¹	658±245	570±161	477±195	0.073
MAPR (palmitate), μmol ATP·mmol⁻¹ acetyl-CoA·min⁻¹	488±169	447±86	429±169	0.616
MAPR (succinate), μmol ATP·mmol⁻¹ acetyl-CoA·min⁻¹	149±35	118±48	131±76	0.521
Relative mitochondrial DNA copy number^#	631±69	804±67	525±35	<0.001	0.041	0.140

Data are presented as mean±sd, unless otherwise stated. MAPR: maximal mitochondrial ATP production rate (normalised to citrate synthase activity for various mitochondrial substrates). ^#: relative to nuclear DNA copy number.