Table 3.

Precursor and product enrichment of skeletal muscle protein, DNA, and membrane phospholipids following ²H₂O labeling

Fraction	Older exercise		Young sedentary
	CHO	PRO
DNA
Precursor (%)	6.74 ± 2.50	5.69 ± 1.85	3.03 ± 1.10
Product (%)	0.42 ± 0.22	0.28 ± 0.14	0.05 ± 0.04
Protein
Precursor (%)	4.34 ± 1.56	3.97 ± 2.75	2.83 ± 0.81
Product (%)	1.91 ± 0.60	1.58 ± 1.00	1.20 ± 0.33
Phospholipids
Precursor (%)	6.96 ± 2.42	6.39 ± 1.81	7.53 ± 2.85
Product (%)	2.79 ± 0.82	2.36 ± 0.82	0.41 ± 0.08

Data are means ± sd. Older exercise groups were labeled for 6 wk; young sedentary group was labeled for 4 wk.