Table 2.

Comparison between serum, CSF, and synovial fluid pre-operative levels of PEA, OEA, AEA, and 2-AG (ng/ml) in male and female OA patients (mean ± S.E.). For each metabolite the number of samples for each of the two groups is indicated.

	Male	Female	P value
PEAser	1.74 ± 0.14 (N=20)	1.70 ± 0.12 (N=24)	0.813
OEAser	2.12 ± 0.24 (N=20)	2.27 ± 0.21 (N=24)	0.638
AEAser	0.22 ± 0.02 (N=20)	0.26 ± 0.02 (N=24)	0.139
2-AGser	2.98 ± 0.35 (N=20)	3.20 ± 0.34 (N=25)	0.659
PEAcsf	0.16 ± 0.02 (N=18)	0.15 ± 0.02 (N=21)	0.729
OEAcsf	0.03 ± 0.00 (N=19)	0.04 ± 0.01 (N=20)	0.725
AEAcsf	0.01 ± 0.00 (N=19)	0.01 ± 0.00 (N=22)	0.819
2-AGcsf	0.10 ± 0.01 (N=19)	0.11 ± 0.02 (N=19)	0.641
PEAsyn	0.85 ± 0.07 (N=12)	0.86 ± 0.06 (N=10)	0.861
OEAsyn	1.11 ± 0.13 (N=14)	1.13 ± 0.10 (N=10)	0.879
AEAsyn	0.09 ± 0.01 (N=14)	0.09 ± 0.01 (N=10)	0.693
2-AGsyn	1.33 ± 0.21 (N=13)	1.51 ± 0.30 (N=10)	0.634