Role of the liver in splanchnic extraction of atrial natriuretic factor in the rat

Mesenteric, hepatic and splanchnic extraction of C-terminal and
N-terminal atrial natriuretic factor was investigated in male
Sprague-Dawley rats. Plasma concentrations (mean ± S.E.M.) of
C-terminal atrial natriuretic factor were 55.0 ± 6.1 fmol/ml, 31.2
± 4.0 fmol/ml and 23.5 ± 3.3 fmol/ml (n = 12) in the abdominal
aorta, the portal vein and the hepatic vein, respectively.
N-terminal atrial natriuretic factor plasma levels in these vessels
were 3031 ± 756 fmol/ml, 2264 ± 661 fmol/ml and 1618 ± 496 fmol/ml
(n = 6), respectively. Although the mesenteric extraction ratio was
higher (p < 0.05) for C-terminal atrial natriuretic factor (42%
± 6%) than for N-terminal atrial natriuretic factor (28% ± 4%),
there were no significant differences in the hepatic extraction
ratio (41% ± 5% vs. 39% ± 6%) and the splanchnic extraction ratio
(56% ± 5% vs. 50% ± 7%). These data suggest a major role of the
liver in the splanchnic extraction of C-terminal and of N-terminal
atrial natriuretic factor in the rat. (HEPATOLOGY 1992;16:790-793.