TABLE 2.

6β-Naltrexol brain and liver K_P ratios during postnatal development

Age	Survival Time (min)	Plasma (ng/ml)	Brain (ng/g)	Liver	Brain/Plasmaa Ratio	Liver/Plasma Ratio
	min	ng/ml	ng/g	ng/g
E17	45	930 ± 220 (ad)	2780 ± 1670*	4400 ± 2580*	2.9	4.7
P7	45	3513	3030 ± 340	15,220 ± 1750	0.86	4.3
P14	45	1410 ± 370	2860 ± 800	5050 ± 1260*	2	3.6
P20	20	1070 ± 100	350 ± 20*	1830 ± 70*	0.33	1.7
P32	20	1160 ± 730	260 ± 80	1510 ± 640	0.22	1.3
P50	45	430 ± 40	150 ± 10*	820 ± 80*	0.35	1.9
Adult	45	930 ± 220	310 ± 70*	3200 ± 1600*	0.34	3.4

ad, adult plasma.

^aBrain/Plasma units = ml/g.

^*P < 0.05 for comparison of brain or liver to plasma.