title: Reduction of enzyme efflux from isolated skeletal muscle and heart by diethylstilbestrol.
abstract: It was previously shown that the efflux of creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) from isolated mouse gastrocnemius was reduced 20% by a daily dose of 10 mug of diethylstilbestrol (DES) given for 14 or 21 days. The present study was designed to ascertain to what degree increasing doses of DES could suppress the CPK and LDH efflux from isolated skeletal muscle, and if DES affected heart in a similar manner. A total of 36 mice were injected with saline or 20, 100, 250 and 500 mug DES in saline daily for 14 days. The spontaneous efflux of CPK and LDH from the isolated gastrocnemius and heart was then compared in control and treated mice. The reduction in efflux was partially dose-dependent: increasing doses up to 100 mug DES per day, progressively reduced skeletal muscle efflux of CPK to 50% and LDH to 30%; higher doses had no additional effect. LDH efflux from heart was similarly reduced by DES, but over a narrower dosage range. This is the first agent shown to lower the spontaneous enzyme efflux from these two organs. These studies confirm that DES lowers the enzyme efflux from skeletal muscle; and though this effect is dose-related, the efflux could not be completely suppressed. The mechanism responsible for this reduction remains to be determined.
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003402:Creatine Kinase / Q000378:metabolism; D003864:Depression, Chemical; D004054:Diethylstilbestrol / Q000494:pharmacology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009132:Muscles / Q000201:enzymology*; D009206:Myocardium / Q000201:enzymology*; D009929:Organ Size / Q000187:drug effects; D013997:Time Factors
chemical_list: D004054:Diethylstilbestrol; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase