Research progress in CTRP9, a novel adipokine

C1q/TNF-related protein 9 (CTRP9), a newly identified adipokine, shows high homology to adiponectin and exerts such positive effects as metabolic regulation, cardioprotection, vasorelaxation and improvement of endothelial function. In this paper, the structure, oligomeric form, tissue expression and secretion of CTRP9 as well as its physiological functions are reviewed.