Comparison of the testosterone-to-cortisol ratio values obtained from hormonal assays in saliva and serum

Testosterone (T) and cortisol (C) were determined in serum and saliva, sampled simultaneously, from triathletes and karate athletes, in order to determine the T:C ratios in those body fluids and the relationship between them, as well as to assess the salivary T:C ratio as a measure of the so-called anabolic-catabolic index. Mean salivary T:C (value (1.67±0.85) was nearly 3-fold lower than that obtained for serum (4.87±1.86). Salivary and serum values were strongly correlated with one another (r=0.874, p<0.001) but the relationship depended on the range of cortisol concentrations in serum, the slope of the salive - serum regression line being significantly lower for serum cortisol concentrations over 600 nmol.l -1 than for concentrations below that value (0.305 and 0.380, p<0.05, respectively). It has been concluded that the salivary T:C ratio, based on values reflecting the levels of biologically active fractions of T and C in circulation, is a better measure of metabolic equilibrium conditioned by those hormones than the corresponding ratio obtained from total concentrations in serum.