title: Ascorbate in the guinea pig lens: dependence on drinking water supplementation.
abstract: 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.
authors.affiliation: St. Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden. vino.mody@ste.ki.se
authors.forename: Vino C
authors.initials: VC
authors.lastname: Mody
authors.forename: Manoj
authors.initials: M
authors.lastname: Kakar
authors.forename: Ase
authors.initials: A
authors.lastname: Elfving
authors.forename: Per G
authors.initials: PG
authors.lastname: Söderberg
authors.forename: Stefan
authors.initials: S
authors.lastname: Löfgren
mesh_terms: 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*
chemical_list: D001205:Ascorbic Acid