title: Ultrastructural changes in skeletal muscles of rats treated neonatally with 6-mercaptopurine.
abstract: The purpose of this study was to characterize the ultrastructural changes in the muscles of 2- and 6-month-old rats that were injected with 6-mercaptopurine monohydrate (6-MP) at 2 mg base/kg sc daily from 2 to 22 days of age. The earliest, usually subsarcolemmal alterations, were disorganization of fibrils at the Z-bands with excessive Z-band-like material and loss of myofibrils. In the most extensive lesions, the entire fiber was involved, with vacuoles within the disorganized fibrils. The peripheral nerves and vessels were unremarkable. Thus 6-MP-induced changes appear to be primarily myogenic in origin.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D005260:Female; D008297:Male; D015122:Mercaptopurine / Q000633:toxicity*; D009132:Muscles / Q000187:drug effects / Q000648:ultrastructure*; D051381:Rats
chemical_list: D015122:Mercaptopurine