title: Absorption, distribution and endogenous excretion of zinc by rats fed various dietary levels of inorganic tin and zinc.
abstract: Three studies were designed to determine the effects of various levels of tin (less than 1, approximately 100, approximately 200, approximately 500 and approximately 2000 micrograms tin/g diet) and zinc (approximately 15, approximately 30, approximately 52 micrograms zinc/g diet) on the metabolism of zinc by growing rats. Retention of zinc in tibia, kidney, liver and plasma was decreased significantly when rats consumed greater than or equal to 500 micrograms tin/g diet. Tibia zinc levels were also sensitive to lower levels of dietary tin, i.e., even 100 micrograms tin/g diet when rats were fed 51.8 micrograms zinc/g diet. Apparent absorption of zinc was significantly less when rats were fed approximately 200 or approximately 500 micrograms tin/g diet rather than a control diet containing 15.8 micrograms zinc/g diet and significantly less when rats were fed approximately 500 micrograms tin/g diet rather than approximately 200 micrograms tin/g diet with 29.7 micrograms zinc/g diet. The effect of dietary tin on fecal excretion of endogenous zinc and true absorption of zinc seemed to be dependent on the dose. Rats fed approximately 2000 micrograms tin/g diet lost significantly more zinc of endogenous origin in the feces than control animals. A significant decrease in true absorption of zinc was observed among those rats fed approximately 500 micrograms tin/g diet with 29.7 micrograms zinc/g diet. Increased consumption of zinc resulted in decreased apparent absorption of zinc, increased losses of endogenous zinc in the feces, and decreased true absorption of zinc.
mesh_terms: D000818:Animals; D001835:Body Weight; D004032:Diet; D007408:Intestinal Absorption; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014001:Tin / Q000008:administration & dosage / Q000494:pharmacology*; D014018:Tissue Distribution; D015032:Zinc / Q000008:administration & dosage / Q000378:metabolism*
chemical_list: D014001:Tin; D015032:Zinc