Can cultured teleost hepatocytes show temperature acclimation?

Hepatocytes were prepared from 15 degrees C acclimated catfish (Ictalurus punctatus) and maintained in primary culture for 20 days on biomatrix at 7, 15, and 25 degrees C without hormones or serum to determine if cells can directly adapt to temperature. Specific activities of cytochrome-c oxidase, NADH-cytochrome c reductase, citrate synthase, and glucose-6-phosphate dehydrogenase showed acclimatory rate compensation (7 greater than 15 greater than 25 degrees C cultured); 6-phosphogluconate dehydrogenase had activity changes of 15 greater than 7 greater than 25 degrees C cultured; activity of lactate dehydrogenase occurred in the series 7 greater than 15 = 25 degrees C. Protein synthesis of freshly isolated hepatocytes from catfish acclimated to the three temperatures exhibited acclimatory rate compensation. In contrast, protein synthesis of cultured hepatocytes occurred in the series 15 greater than 25 greater than 7 degrees C cultured. Protein degradation was highest at 25 degrees C followed by cells at 15 and 7 degrees C. Cultured hepatocytes showed incomplete temperature acclimation in vitro by way of enzyme activity changes and of protein synthesis. This suggests that some factor(s), such as hormones, is probably necessary to mediate the full temperature-acclimation process.