Sodium deprivation growth failure in the rat: alterations in tissue composition and fluid spaces

J Nutr. 1987 Sep;117(9):1623-8. doi: 10.1093/jn/117.9.1623.

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.

MeSH terms

  • Animals
  • Body Composition* / drug effects
  • Body Weight / drug effects
  • Bone and Bones / metabolism
  • Bone and Bones / pathology
  • Calcium / metabolism
  • Eating
  • Extracellular Space / physiology*
  • Growth Disorders / etiology*
  • Growth Disorders / pathology
  • Growth Disorders / physiopathology
  • Muscles / metabolism
  • Muscles / pathology
  • Rats
  • Rats, Inbred Strains
  • Sodium / deficiency*
  • Sodium / metabolism
  • Sodium, Dietary / administration & dosage*
  • Sodium, Dietary / pharmacology

Substances

  • Sodium, Dietary
  • Sodium
  • Calcium