IN-VIVO EFFECTS OF CARDIOTROPHIN-1

Cardiotrophin-1 (CT-1) is a recently discovered cytokine that was isol ated based on its ability to induce cardiac myocyte hypertrophy in vit ro, In this study, the effects of chronic administration of CT-1 to mi ce (0.5 or 2 mu g by intraperitoneal injection, twice a day for 14 day s) were determined, A dose-dependent increase in both the heart weight and ventricular weight to body ratios was observed in the treated gro ups, The body weights of the animals were unaffected, These results in dicate that CT-1 can induce cardiac hypertrophy in vivo, CT-1 was not specific for the heart, however, It stimulated the growth of the liver , kidney, and spleen, and caused atrophy of the thymus, CT-1 administr ation also increased the platelet counts by 70%, with no change in mea n platelet volume. Pied blood cell counts were increased in the treate d animals, and there was a concomitant increase in haemoglobin concent ration. Thus, CT-I has a broad spectrum of biological activities in vi vo. This observation is consistent,vith previous in-vitro findings sho wing that the mRNA for CT-1 is expressed in several tissues, and that CT-1 can function through binding to the leukaemia inhibitory factor ( LIF) receptor and signalling through the gp130 pathway.