Table 2. Nucleotide levels in dark- or light-adapted murine retinas, determined by HPLC.

Retinas were obtained from 16 dark-adapted mice that were either kept in the dark for 4 hr, or exposed to 4 hr bright light (1600 lux). HPLC determinations, with numbers indicating Mean ± S.E.M, with n = 4 biological replicates.

	Pmol/mg protein
	DARK	4 hr BL
GMP	557.21 ± 88.5	916.31 ± 81.1
GDP	762.57 ± 47.8	1174.11 ± 109
GTP	2461.53 ± 178.1	2737.29 ± 310.6
AMP	731.84 ± 125.4	1246.16 ± 69.8
ATP	1579.69 ± 110.5	2759.18 ± 226
GTP/ATP	1.56	0.99