Time course of vitamin C distribution and absorption after oral administration in SMP30/GNL knockout mice.
OBJECTIVE
Because vitamin C (VC) has multiple metabolic and antioxidant functions, we investigated the movement of VC throughout the tissues of senescence marker protein-30 (SMP30)/gluconolactonase (GNL) knockout (KO) mice.


METHODS
SMP30/GNL KO mice, which cannot synthesize VC in vivo, were divided into two groups: VC sufficient and VC deficient. Starting at 2 mo of age, both groups had free access to water containing 1.5 and 0.0375 g/L of VC for 1 mo.


RESULTS
The average rate of VC retention in 20 tissues of VC-deficient SMP30/GNL KO mice was only 13.7% of that in VC-sufficient mice. Tissues that retained over 20% of VC were the cerebellum, white fat, testes, eyeballs, and pancreas, and those with less than 5% VC were the kidneys and heart. These results clearly indicate the different VC retention capacities among tissues. Next, we examined the time course of VC distribution and absorption in VC-deficient SMP30/GNL KO mice. After oral VC administration, VC content in the liver and kidney peaked at 3 h and then decreased. VC content in the lungs, adrenal glands, skin, white fat, and pancreas peaked at 6 h and in the cerebellum, cerebrum, skeletal muscles, eyeballs, thyroid gland, and testes at 12 h.


CONCLUSIONS
In this study, we found that exogenous VC administered orally in VC-deficient SMP30/GNL KO mice was distributed at distinctly different rates within individual tissues. The SMP30/GNL KO mice used in this study are a useful animal model that provides unique opportunities for investigating VC movement and metabolism in the entire body.
Iwama
Mizuki
M
Department of Geriatrics and Vascular Medicine, Tokyo Medical and Dental University, Tokyo, Japan.
Shimokado
Kentaro
K
Maruyama
Naoki
N
Ishigami
Akihito
A
D000284:Administration, Oral; D000818:Animals; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001206:Ascorbic Acid Deficiency / Q000235:genetics / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D007408:Intestinal Absorption; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D014018:Tissue Distribution
D002135:Calcium-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C513324:Rgn protein, mouse; D002265:Carboxylic Ester Hydrolases; C020579:gluconolactonase; D001205:Ascorbic Acid