It seemed to stress the liver of the pigs in this study, but the dosages used were quite high.
Vet Hum Toxicol 2002 Oct;44(5):269-71 Related Articles, Links
Effects of repeated growth-promoting doses of clenbuterol on the hepatic function of female pigs.
Gojmerac T, Pleadin J, Zuric M, Mirko L, Stipica C.
Department of Chemistry, Croatian Veterinary Institute, Zagreb.
The effect of repeated administration of clenbuterol in a growth-promoting dose on hepatocellular integrity of female pigs was assessed by correlating histopathologic lesions in the livers of dosed pigs with changes in serum ALT, AST, GGT and AP activities. The experiments were carried out in 12 (6 control and 6 treated) female pigs (Fl generation Swedish Landrace and Large Yorkshire) 6-7 mo and 80-100 kg bw. Experimental animals were treated with 10 microg clenbuterol/kg bw iv twice daily for 25 d prior to being sacrificed. Blood and liver samples were collected. Treated animals had increased serum AP and ALT activities (p< 0.02), whereas serum AST and GGT activities did not significantly change. Mild hyperplasia of biliary ducts, interstitial liver inflammation and hydropic and vacuolar hepatocyte degeneration were observed. These findings indicate that repeated administration of growth-promoting doses of clenbuterol to female pigs adversely affect liver function.