Nuclear alterations in hepatocytes of Arctic char Salvelinus alpinus from acidic high alpine lakes

Abstract

The hepatocyte morphology of Arctic char Salvelinus alpinus from 2 acidic, a circumneutral and 3 alkaline lakes in the Austrian Alps (Tyrol and Styria) was compared with respect to nuclear alterations and related to environmental parameters. Extensive glycogen storage of hepatocyte nuclei could regularly be found in Arctic char from the 2 acidic high mountain lakes. In contrast, in Arctic char from the cirumneutral lake (slightly acidic during winter) nuclear glycogen storage could only be documented in a few specimens. In alkaline lakes, however, nuclear glycogen deposition was absent in 64 out of 65 specimens. Additional nuclear pathology in char of the most acidic lake was evident from a reorganization of nucleolar components. The number of nuclei involved in glycogen storage showed a distinct seasonal pattern which correlated with the intensity of feeding, but not with the seasonality of other environmental parameters (trace metals, temperature, pH).