Long-term melatonin treatment reduces ovarian mass and enhances tissue antioxidant defenses during ovulation in the rat. L.G.A. Chuffa, J.P.A. Amorim, G.R. Teixeira, L.O. Mendes, B.A. Fioruci, P.F.F. Pinheiro, F.R.F. Seiva, E.L.B. Novelli, W. Mello Júnior, M. Martinez and F.E. Martinez. Braz J Med Biol Res 2011; 44: 217-223.

Figure 1. A, Protocol for melatonin treatment based on Zeitgeber time (ZT) corresponding to the environmental circadian time. B, Rats received 100 µg melatonin·100 g body weight-1·day-1, ip, for 60 days.