The effects of high dietary levels of sodium saccharin on mineral and water balance and related parameters in rats.

The effects of sodium saccharin (NaS) treatment on mineral and water balance and a number of related parameters were studied over a 10-day period in 7-month-old Charles River CD rats. Eight groups of 10 male and 10 female rats were studied. In four of the groups the rats were the F1 offspring of rats that had been exposed to NaS at 1, 3, 5 or 7.5% in the diet and the offspring were treated with the same dietary levels of NaS as their parents. Prior treatment in two other groups was modified in order to evaluate the role of in utero exposure to NaS on the study parameters: rats in one group were only exposed in utero via dams fed diets containing 5% NaS while treatment in the other group did not include in utero exposure, but was started at birth via dams fed diets containing NaS and continued at a dietary concentration of 5% NaS. Second-generation rats in another group were fed diets containing 5% sodium hippurate (NaH), a compound with a number of physical and chemical properties similar to those of NaS; this group was included in order to evaluate the specificity of NaS and/or the effect of sodium on the study parameters. A group of untreated rats served as controls. Treatment-related effects were observed in most study parameters. In addition, a number of differences between male and female rats in baseline values and/or in response to NaS administration were observed. With increasing dietary levels of NaS body weights decreased, but there were increases in water consumption, faecal water content, and caecal weights. NaS treatment resulted in increased urine volume and decreased urine osmolality, changes in urine mineral concentrations (increased sodium, decreased potassium and zinc) and increases in fresh and dry bladder weights, bladder-tissue hydration, and mineral concentrations (sodium, potassium, magnesium and zinc) in bladder tissue. The parameters in which clear sex-related differences in baseline values were observed were body weight, food and water consumption, urine volume, urine osmolality, fresh bladder mass, bladder-tissue hydration and the concentrations of sodium, potassium, magnesium and zinc in the bladder tissue. With the exception of urine osmolality, the values were higher in females. Differences between males and females in response to treatment were observed for NaS consumption (increased in females), caecal weight (increased in females), NaS concentration in the urine (increased in males), and the concentration of sodium, potassium, magnesium and zinc in the bladder tissue (increased in males).(ABSTRACT TRUNCATED AT 400 WORDS)