ABSTRACT

Activities are cytokines that are members of the transforming growth factor beta (TGF-β) superfamily. Activins have a number of effects in the body that regulate various growth and differentiation events such as embryogenesis, immune response regulation, wound healing in various systems in the body. The most important factor regulating the functions of activins in the body is the follistatin, also known as ‘activin binding protein’. Follistatin was first described as a protein in the follicle fluid that regulates the release of follicle-stimulating hormone (FSH) from the pituitary. Nowadays, it is known that follistatin is widely synthesized and secreted from many tissues in the body and has many reproductive and non-reproductive functions. Follistatin achieves these effects by binding to activin due to its affinity to activin and inhibiting it. Activin-follistatin system has important roles in renal development and regeneration. It has been shown in many studies that the activins inhibit the development of tubules in the embryological development process of the kidneys. Follistatin inhibits the actions of activins and contributes to the healthy progress of the renal organogenesis process. The role of the activin-follistatin system in renal tissue repair and regeneration was investigated in the ischemia reperfusion model in rats and in the ureteral obstruction-induced fibrosis model. These limited number of studies indicate that exogenous follistatin administration in renal injury may be a new therapeutic approach in renal tubule regeneration. This review summarizes how the activin-follistatin system acts in the process of renal development and recovery of renal damage.