Somatostatin inhibits the Na+/H+ exchange activity of rat hepatocytes in short term primary culture.
Activation of the Na+/H+ exchanger is associated with cell growth and differentiation. Our study has tested whether somatostatin-14 (SS-14), which is a potent inhibitor of liver regeneration, has an inhibitory effect on the Na+/H+ exchange (NHE-1) of rat hepatocytes. We treated hepatocytes with SS-14 prior and after cell culture. NHE-1 activity of short term cultured hepatocytes was estimated with the recovery rate of pHi after 9 min. acid-loading in a sodium free buffer. Cultured with SS-14 (100 nM) inhibited significantly the pHi recovery rate of hepatocytes, dpHi/dt and set point were significantly decreased in the presence of SS-14 in comparison to controls. The resting pHi of hepatocytes was not affected in the presence of SS-14. In contrast, addition of SS-14 after cell culture had no effect on the pHi recovery rate of hepatocytes. Therefore the inhibitory action of SS-14 on NHE-1 activity of rat hepatocytes appears to depend on the presence of the hormone in the early steps of the process of cell growth/adhesion. Inhibition of SS-14 on NHE-1 activity seems to mediate, at least in part, its inhibition on liver regeneration.
Ye
W Z
WZ
Faculté de Médecine, INSERM-U. 260, Marseille, France. ye@cochin.inserm.fr
Mathieu
S
S
Marteau
C
C
D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D008099:Liver / Q000166:cytology / Q000378:metabolism; D051381:Rats; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism*; D013004:Somatostatin / Q000378:metabolism* / Q000494:pharmacology
D017923:Sodium-Hydrogen Exchangers; C069139:growth factor-activatable Na-H exchanger NHE-1; D013004:Somatostatin