The effects of aging and calorie restriction on plasma nutrient levels in male and female Emory mice

We examined the effect of diet, age (4.5, 13 and 23 months), and sex on pla sma levels of retinol, tocopherol, ascorbate, cholesterol, glucose and glyc ohemoglobin in male and female Emery mice which were fed control (C) and 50 % calorie restricted (R) diets. Results showed that C fed animals tended to have higher levels of plasma ascorbate (50-71%), cholesterol (23-71%), glu cose (38-81%) and glycohemoglobin (50%). However, these diet differences va ried with the age and sex of the animals. Plasma retinol levels were lower only in R males vs. C males (50%). Novel sex-related differences in levels of plasma retinol (2-fold higher in C male mice than in C or R female mice) are described. Aging was associated with trends towards lower levels of pl asma ascorbate (14-25%), glucose (34-36%) and glycohemoglobin (47-57%) from 4.5 to 23 months of age. However, these age differences depended upon the diet and sex of the animals. These data suggest that lower plasma levels of glucose, glycosylated hemoglobin and cholesterol may be causally related t o the life extension noted in R animals since elevated levels of these moie ties have been related to aging. Since oxidative stress is thought to be ca usally related to aging it appears unlikely that retinol, tocopherol and as corbate are causally related to R-induced life-extension. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.