title: Sodium deprivation growth failure in the rat: alterations in tissue composition and fluid spaces.
abstract: Dietary control of sodium intake was utilized in weanling rats to study the relationships among body growth, tissue composition and extracellular fluid volume (ECFV). Forty 3-wk-old rats were divided into groups receiving 30, 150, 300, 600 or 900 mu eq sodium/d for 5 wk. The minimal daily requirement for normal growth was 300 mu eq Na, or about 60 mu eq/g of new growth. Lower doses caused dose-related growth failure associated with a reduced ECFV. Analyses of carcass, muscle and bone composition were carried out. In sodium-deprived animals there was retarded growth of protoplasm, fat and bone; the mineral composition of muscle was not altered, whereas in bone calcium concentration was reduced. Plasma concentrations of sodium, potassium and chloride remained normal. Pair-feeding indicated that sodium-deficiency growth retardation could not be attributed to starvation. Sodium-deficient animals ingested a greater amount of food per gram of weight gain, possibly reflecting an increased energy expenditure. Sodium deprivation initially permitted protoplasmic growth to proceed at a rate disproportionate to that of the ECFV. Subsequently, both continued to grow at a reduced but similar rate, suggesting that ECFV may be a controller of protoplasmic growth.
authors: Department of Pediatrics, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark 07103-2757.
authors: B P
authors: BP
authors: Fine
authors: A
authors: A
authors: Ty
authors: N
authors: N
authors: Lestrange
authors: O R
authors: OR
authors: Levine
mesh_terms: D000818:Animals; D001823:Body Composition / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D001842:Bone and Bones / Q000378:metabolism / Q000473:pathology; D002118:Calcium / Q000378:metabolism; D004435:Eating; D005110:Extracellular Space / Q000502:physiology*; D006130:Growth Disorders / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D009132:Muscles / Q000378:metabolism / Q000473:pathology; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000172:deficiency* / Q000378:metabolism; D012982:Sodium, Dietary / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D012982:Sodium, Dietary; D012964:Sodium; D002118:Calcium