Cosine adjusted curve of late-treated and early-treated diabetic animals. Diabetic animals received late treatment (left column) or early treatment (right column) with insulin (A, D), melatonin (B, E) or a combination of both hormones (C, F). The cosine adjusted curve was obtained with Cosinor analyses for each day of the recording of each animal. The resulting data for each day (24 bins) was plotted throughout the recording (55 days). Only days that showed a 24 h oscillation in the Cosinor analysis were used. Lines indicate the moments of the STZ injection, the treatments and their interruption.