Sexual dimorphism in relationships between of plasma bilirubin and some neuro-endocrine parameters

Abstract

Background. Earlier we found that plasma uric acid, urea and creatinine causes modulating effects on neuro-endocrine parameters, as well as anxiety, but these effects are significantly different in men and women of different ages. The purpose of this study is to analyze the relationships between the plasma bilirubin level and some psycho-neuro-endocrine parameters in the same cohort. Materials and Methods. The object of observation were almost healthy volunteers: 31 males (24÷69 y) and 30 females, from among them 18 postmenopausal (48÷76 y) and 12 of reproductive age (30÷45 y). In basal conditions we determined plasma levels of bilirubin and adaptation hormones, estimated the severity of the trait and reactive anxiety, recorded the ongoing HRV and EEG. After 4 or 7 days, repeated testing was performed. Results. By building regression models with stepwise exclusion, it was found that in men plasma bilirubin upregulates the variability of β- and α-rhythms as well as PSD of β-rhythm in T4 and Fp2 loci, but downregulates the variability of θ-rhythm, PSD of β-rhythm in P4 and δ-rhythm in T6 loci as well as the trait anxiety. The measure of determination is 42,6% In postmenopausal women, bilirubin downregulates the PSD of β-rhythm in T6 locus, but upregulates the Testosterone plasma level, vagal tone as well as PSD of ULF and VLF bands HRV. The degree of determination of neuro-endocrine parameters is 59,2%. In women of reproductive age bilirubin upregulates the PSD of β-rhythm in T4 locus while downregulates the amplitude of θ- and β-rhythms, PSD of β-rhythm in 5 loci, of α-rhythm in 5 other loci as well as the Entropy of EEG in T5, P4 and C4 loci. The degree of determination of EEGs parameters is 97,8%. Conclusion. Plasma bilirubin has a modulating effect on psycho-neuro-endocrine parameters, but this effect is significantly different in men and women of different ages, which is due, apparently, to the influence of sex hormones on the expression of Ah receptors in neurons.