Effects of acute hepatic damage on natriuresis and water excretion after acute normal saline loading in rats

摘要

AIMS To investigate the relationship between the liver functional impairment and sodium and water retention. METHODS Acute liver damage model was established with carbon tetrachloride (CCl_4) administration to male Sprague-Daw-ley rats. Twenty-four and 48 hours later after CCl_4 administration, the excretion of acute sodium and water load was examined, and 24 hours later after normal saline administration, the excretion of acute sodium and water load was examined in control group. The concentration of plasma caffeine was analysed with high pressure liquid chromatograph (HPLC). The half life time of plasma caffein (Caft 1/2) served as a quantitative index of hepatic function. Plasma ALT was measured with Reitman method. The hepatic tissue was sectioned in the same site for water content measurement and pathological observation. The serumal and urinary sodium was measured with flame photometry. RESULTS Twenty-four hours later after CCl_4 administration, plasma alanine aminotransferase (ALT, n = 6, 37.5 ± 12.6 → 189.4 ± 34.4 U, P < 0.01) and water content of hepatic tissue (n = 6, 70.0% ± 1.1%→73.0% ± 1.0%, P < 0.01) rose significantly, Caft 1/2 was prolonged significantly (94.9± 18.9→ 326.4±85.8 minutes, P < 0.01). The renal function of excretion of acute salt and water load declined obviously (n = 6, Na~+: 92.4% ±14.1%→50.1% ±13.1%, P < 0.01; H_2O: 86.3% ± 14.3% →42.1% ± 8.8%, P < 0.01). Forty-eight hours later, the indexes above somewhat recovered, but were still markedly different from those of the control. Furthermore, the relationships between Caft 1/2 and ALT (r = 0.752, P < 0.01), and between Caft 1/2 and excretory rate of sodium (r = - 0.634, P < 0.05) and water were still significant (r= -0.612, P < 0.01). CONCLUSIONS Caft 1/2 is a good index to assess the degree of hepatic damage. The hepatic dysfunction may be a factor causing the renal excretory impairment to the acute sodium and water load.