Figure 5.

Linear regression analysis between serum testosterone and serum estradiol during 24-hours sampling at different pubertal stages in healthy boys. Boys followed up by repeated measurements were randomized to participate once in the analyses. Serum estradiol correlated significantly with serum testosterone: r = 0.38, p < 0.001 and r = 0.58, p < 0.001 for early to mid-puberty and late puberty, respectively. Estradiol values below the detection limit are set to the expected value of 2 pmol/L.