- Relaxin modulates cardiac fibroblast proliferation, differentiation, and collagen production and reverses cardiac fibrosis in vivo. Samuel, C.S., Unemori, E.N., Mookerjee, I., Bathgate, R.A., Layfield, S.L., Mak, J., Tregear, G.W., Du, X.J. Endocrinology (2004)