The effects of vitamin C administration, acute food deprivation, and acute food intake on vitamin C levels in different brain areas of guinea pigs.

Vitamin C is crucial for the brain. We aimed to investigate the effects of vitamin C administration following 24 hours of acute food deprivation and 24 hours of acute food intake on changes in vitamin C levels in different brain areas of guinea pigs. Vitamin C was administered as a single intraperitoneal dose (500 mg kg(-1) body weight) both before acute food deprivation and before acute food intake. At the end of our study, we measured the vitamin C levels in cerebral cortex lobes, brain stem structures, hypophysis, hypothalamus, cerebellum, hippocampus, and amygdala. Vitamin C levels in the frontal and parietal lobes were found to be significantly higher in animals pretreated with vitamin C prior to 24 hours of food deprivation (p < 0.05). Temporal lobe vitamin C level was significantly lower in animals that were subjected to 24 hours of acute food intake following 24 hours of food deprivation (p < 0.05). Increased vitamin C levels were observed in the occipital lobe of all animals that received vitamin C administration (p < 0.05). Vitamin C levels in the brain stem structures such as mesencephalon and pons were significantly decreased in animals pretreated with vitamin C before normal feeding (p < 0.05). Vitamin C level in the hypothalamus was significantly increased after 24 hours of food deprivation (p < 0.05). In conclusion, different areas of the brain may differ in terms of vitamin C content during nutritional changes with or without vitamin C pretreatment, such as 24 hours of food deprivation or 24 hours of food intake following 24 hours of food deprivation. These differences may be attributed to several functions of vitamin C which may occur under these circumstances.

Relationships between tensile strength, ascorbic acid, hydroxyproline, and zinc levels of rabbit full-thickness incision wound healing.

PURPOSE: This work was carried out to follow up the healing of full-thickness incision wounds opened on the back skin of rabbits in order to gain insight into the periodical correlation among such factors as ascorbic acid, collagen (hydroxyproline), the zinc content, and tensile strength of wound tissue. The need to provide vitamin C or zinc supplements after such wound incisions is also discussed. METHODS: Full-thickness incision wounds and the ascorbic acid and hydroxyproline levels were measured in 24 rabbits by spectrophotometric methods on day 0 and on the 3rd, 5th, 7th, and 15th days after operation. The tensile strength was measured by a polygraph using a force displacement transducer. The zinc levels of the wounds were measured by atomic absorption spectrophotometry. RESULTS: The zinc and hydroxyproline levels reached the peak levels on the 5th day, but the tensile strength of wound increased sharply on the 7th day after wounding while the zinc levels did not change. These results indicated that in the first 7 days of wound healing, high levels of ascorbic acid, hydroxyproline, and zinc cumulation occurred in the wound tissue, and the tensile strength reached its highest level on the 15th day without any supplementation. CONCLUSION: The supplementation of zinc and/or ascorbic acid should therefore be given just at the beginning of the wounding period, especially if there is deficiency of these nutrients.