Lysosomal alterations in heart, skeletal muscle, and liver of hyperthyroid rabbits

R. S. Decker, K. Wildenthal

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


Daily administration of L- or D-thyroxine for 1 week produced hypertrophy of the heart and atrophy of skeletal muscle and liver. The myocardial hypertrophy was accompanied by a rise in the activity of cathepsin D but not of cathepsin B; this was correlated with an increase in cathepsin-D-rich interstitial cells while the number of cathepsin-D-positive lysosomes in myocytes was decreased, as assessed from immunohistochemistry. In atrophying skeletal muscle (soleus and tibialis anterialis), large increases in the activities of cathepsins B and D were present. Immunohistochemical localization of cathepsin D revealed that in thyrotoxic striated muscle cells this acid proteinase had become localized diffusely in the paranuclear myoplasm. The atrophying liver of thyrotoxic rabbits also developed large increases in cathepsin D activity, but in this organ the increase was correlated with an increased number of cathepsin-D-positive secondary lysosomes without diffuse extralysosomal deposits. These observations indicate that changes in lysosomes and lysosomal enzyme activities elicited by thyrotoxicosis are tissue-specific. In some organs, the changes may be associated with net changes in protein balance or with tissue injury, but the exact functional significance of the lysosomal alterations remains uncertain.

Original languageEnglish (US)
Pages (from-to)455-465
Number of pages11
JournalLaboratory Investigation
Issue number5
StatePublished - 1981

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Molecular Biology
  • Cell Biology


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