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Fluid and electrolyte handling in Long Evans and Brattleboro rats following injection of polyethylene glycol.
Author(s) -
Bennett T,
Gardiner S M
Publication year - 1986
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1986.sp016334
Subject(s) - kaliuresis , diuresis , natriuresis , oliguria , evans blue , vasopressin , endocrinology , medicine , chemistry , polydipsia , polyuria , polyethylene glycol , thirst , kidney , renal function , organic chemistry , diabetes mellitus
1. Intake and output of water, Na+ and K+ were measured in Long Evans and Brattleboro rats (deficient in hypothalamic and pituitary vasopressin) before and after subcutaneous injection of polyethylene glycol (PEG) sufficient to cause a substantial hypovolaemia. 2. In the Long Evans rats an initial fluid retention (due to oliguria and polydipsia) was accompanied by Na+ retention and K+ loss. On the second day there was a diuresis but Na+ retention persisted until days 3 and 4 when there was a natriuresis. 3. Brattleboro rats initially also showed fluid retention but this was achieved by hypodipsia with a greater oliguria; there was an accompanying retention of Na+ and K+. On the second day, a reduced fluid balance was still accompanied by Na+ retention but associated with kaliuresis. Diuresis and natriuresis occurred on the third day after PEG injection. 4. Thus, rats deficient in vasopressin respond to hypovolaemia by retaining fluid. The renal actions of aldosterone do not explain fully the changes in renal electrolyte handling.