[Fluorine excretion in urine and feces of rats dependent on the source of this element and content of protein in the diet].

Wistar rats of both sexes were fed semisynthetic diets containing 12 or 24% of protein derived from casein or from krill meal, as well as comprising fluorine (357 mg/kg diet) either from krill meal or from sodium fluoride. After 7, 14 and 32 weeks urine and feces were collected for constructing the fluorine balance. It was found that rate fed krill meal excrete fluorine mainly in feces, and those administrated sodium fluoride--mainly in urine. A higher dietary protein level leads to enhanced fluorine excretion. Fluorine from krill meal is definitely less able to be assimilated than that from sodium fluoride. When fluorine administration is discontinued, this element is released from the organism and is excreted mainly in feces.