cDNA cloning of rat cardiotrophin-1 (CT-1): augmented expression of CT-1 gene in ventricle of genetically hypertensive rats.

Cardiotrophin-1 (CT-1) is a novel cytokine that was discovered from mouse embryoid bodies by means of expression cloning. It induces hypertrophy in cultured myocytes by activating a gp130 signaling pathway. To investigate the expression of the CT-1 gene in both normal adult and genetically hypertensive rats, we cloned rat CT-1 cDNA. The amino acid sequence is 94% identical to that of mouse CT-1. A significant amount of CT-1 mRNA was expressed in the ventricle of adult rats and also detected in the lung, kidney, liver, skeletal muscle, stomach and urinary bladder. Northern blot analysis revealed that the CT-1 mRNA level is significantly augmented in the ventricle of 12-week-old spontaneously hypertensive rats-stroke prone/Izm at a stage of established hypertension, suggesting a possible relevance of CT-1 to ventricular hypertrophy.