Correlations between heme precursors and the analytes selected. (a) correlation coefficients of PBG, ALA and F with all the analytes studied. Dotted and solid lines indicate a significance level at p = 0.05 and p = 0.01, respectively. The negative correlation between cortisol and heme precursors was of a similar magnitude to that of positive correlation obtained between cortisol and its direct precursor (corticosterone, B) or its direct product (cortisone, E). (b) correlation found between both heme precursors and the PT/5β-THF ratio (main metabolites of 17-hydroxy-progesterone and cortisol, respectively). The adrenal hormonal imbalance (ratio between the 17-hydroxy-progesterone precursor and the cortisol product) is correlated with the heme precursors detected in urine.