Effects of isoprenaline treatment on the rat liver parenchyma. Ultrastructural investigations.

Ultrastructural modifications of liver cells were studied in adult rats treated with high doses of isoprenaline for 8 days and subsequently sacrificed at various times up to 25 days from the beginning of treatment. The most evident changes were observed at the earliest times after the end of treatment. They involved both the nucleus (changes in shape and chromatin organization) and cytoplasmic organelles such as the rough endoplasmic reticulum and the smooth endoplasmic reticulum, the latter exhibiting marked dilation and increase, while glycogen generally appeared to be decreased. At later times after the end of treatment, these changes tended to disappear, while there was an increase of peroxisomes and particularly of lysosomes, which exhibited a clearly polymorphic pattern.