Ascorbate in the guinea pig lens: dependence on drinking water supplementation.
OBJECTIVE
To investigate whether lens ascorbate concentration can be elevated with drinking water supplementation.


METHODS
Pigmented guinea pigs received drinking water supplemented with L-ascorbate, concentration 0.00, 2.84, 5.68 or 8.52 mm for a duration of 4 weeks. In addition, the chow fed to all animals contained 125 mmol L-ascorbate per kg of chow. At the end of the supplementation period, the guinea pigs were killed. Each lens was extracted. The lens was processed and ascorbate concentration was measured using high performance liquid chromatography (HPLC) with 254 nm ultraviolet radiation detection. The data were analysed with regression.


RESULTS
At the end of the test period, all lenses were devoid of cataract as observed by slit-lamp examination. All lenses contained a detectable concentration of ascorbate. Estimated 95% confidence intervals for mean animal-averaged lens ascorbate concentrations (micromol/g wet weight of whole lens) per group were 0.51 +/- 0.04 (0.00 mm; n = 6), 0.70 +/- 0.18 (2.84 mm; n = 6), 0.71 +/- 0.11 (5.68 mm; n = 5), and 0.71 +/- 0.06 (8.52 mm; n = 6). Animal-averaged lens ascorbate concentration [Asc(lens)] (micromol/g wet weight lens) increased with ascorbate supplementation in drinking water [Asc(water)] (M), in agreement with the model: [Asc(lens)] = A - Be(-kAsc(water)].


CONCLUSIONS
Lens ascorbate concentration increases with drinking water supplementation in the guinea pig without cataract development. The currently presented method for measurement of whole lens ascorbate content is suitable.
Mody
Vino C
VC
St. Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden. vino.mody@ste.ki.se
Kakar
Manoj
M
Elfving
Ase
A
Söderberg
Per G
PG
Löfgren
Stefan
S
D000284:Administration, Oral; D000818:Animals; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004326:Drinking; D006168:Guinea Pigs; D007908:Lens, Crystalline / Q000378:metabolism*
D001205:Ascorbic Acid