Effect of expansion of extracellular fluid volume on renal phosphate handling.
To examine the specific effect of extracellular fluid (ECF) volume expansion on phosphate excretion studies were performed in thyroparathyroidectomized dogs receiving saline solution intravenously. The natriuresis resulting from ECF volume expansion was consistently accompanied by an increase in phosphate excretion. The possible role of increased filtered load of phosphate was eliminated in experiments in which the filtered load of phosphate was reduced by acute reduction in the glomerular filtration rate. Despite considerable reductions in filtered phosphate, ECF volume expansion resulted in a consistent increase in phosphate excretion. Furthermore, the possible contribution of alteration in blood composition was investigated in experiments in which saline was infused during thoracic inferior vena cava constriction. In these experiments saline infusion failed to increase sodium or phosphate excretion. Cessation of saline infusion and release of caval constriction resulted in a prompt natriuresis and increased phosphate excretion. It is concluded from these studies that extracellular fluid volume expansion results in an increased phosphate excretion in the parathyroidectomized dog. This effect is the specific consequence of ECF volume expansion and is not due to increase in the filtered load of phosphate or alterations in blood composition.
D000818:Animals; D004285:Dogs; D005110:Extracellular Space; D005919:Glomerular Filtration Rate; D007668:Kidney / Q000378:metabolism*; D009318:Natriuresis; D010280:Parathyroid Glands / Q000601:surgery; D010281:Parathyroid Hormone / Q000502:physiology; D010710:Phosphates / Q000378:metabolism* / Q000652:urine*; D011188:Potassium / Q000652:urine; D012964:Sodium / Q000378:metabolism; D013965:Thyroidectomy; D014867:Water / Q000378:metabolism
D010281:Parathyroid Hormone; D010710:Phosphates; D014867:Water; D012964:Sodium; D011188:Potassium
J Clin Invest. 1966 Feb;45(2):179-86
5901504
J Clin Invest. 1966 Apr;45(4):542-51
4287059
Proc Soc Exp Biol Med. 1966 Apr;121(4):1058-63
5937703
Nature. 1966 Jan 22;209(5021):407-9
5920250
Circulation. 1967 Sep;36(3):441-8
6033171
Am J Physiol. 1967 Nov;213(5):1218-24
6054868
Am J Physiol. 1968 Jan;214(1):52-7
5634533
J Clin Invest. 1968 Apr;47(4):761-73
5641617
J Clin Invest. 1968 May;47(5):983-91
5645865
Am J Physiol. 1968 Jul;215(1):71-4
5659345
J Clin Invest. 1968 Aug;47(8):1843-50
4299012
Am J Physiol. 1961 May;200:1099-104
13782897
J Lab Clin Med. 1962 Sep;60:422-32
14006284
J Clin Invest. 1963 Sep;42:1491-6
14065267
J Clin Invest. 1964 Aug;43:1596-607
14201543
Am J Physiol. 1949 Oct;159(1):160-74
15391092
J Clin Invest. 1965 Jul;44:1160-70
14328393