Glucocorticoid-induced alterations in the rabbit heart.
Daily intramuscular injection of the synthetic glucocorticoid, betamethasone, into rabbits for 2 weeks resulted in both gross and microscopic alteration of cardiac muscle. A 30 per cent increase in heart weight was based on increased muscle fiber size occasioned by the deposition of fibrillo-granular material (not glycogen in nature) in the cytosol. At the same time, some myocytes underwent profound myolysis, predominantly at the nuclear poles, occasionally pervading the entire cell. Conventional lysosomes were not increased in number or size, but certain cells possessed prominent cytoplasmic vacuoles that sometimes contained mitochondria. The biochemical basis for these cardiac changes is undetermined, but the obvious ultrastructural damage produced by betamethasone, particularly dissolution of myofibrils, may prove to have clinical significance.
D000818:Animals; D001623:Betamethasone / Q000494:pharmacology*; D003600:Cytosol / Q000473:pathology; D006321:Heart / Q000187:drug effects*; D006984:Hypertrophy; D008247:Lysosomes / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D008929:Mitochondria, Heart / Q000648:ultrastructure; D009206:Myocardium / Q000473:pathology / Q000648:ultrastructure; D009929:Organ Size; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000648:ultrastructure; D013997:Time Factors
D001623:Betamethasone