Experimental and Clinical Physiology and BiochemistryReceived: 25-05-2026
Accepted: 23-09-2026
Published: 28-09-2026
Annotation. Introduction and aim. Sexual dimorphism across animals and human in nervous, endocrine and immune systems has been the subject of a number of studies, but each of them was limited to one system. The aim of this study is the simultaneous comparison of parameters of the autonomic, endocrine and immune systems, which closely interact with each other within the framework of the triune neuro-endocrine-immune complex. The scientific novelty of this work lies in the integrated, system-level analysis of all three regulatory systems simultaneously in the same animals, which distinguishes it from previous studies conducted by other researchers who examined individual systems in isolation. Material and methods. The experiment was conducted on 20 intact rats Wistar line: 10 males and 10 females. We calculated the parameters of the HRV: Mode, Amplitude of the mode and Variational scope as markers of the circulating catecholamines, sympathetic and vagal tones respectively. Among endocrine parameters determined serum levels of main adaptation hormones such as Corticosterone, Aldosterone, Testosterone, Triiodothyronine, as well as Parathyroid hormone and Calcitonin. In addition, the thickness of the glomerular, fascicular, reticular and medullary zones of the adrenal glands was measured in smears under a microscope. The percentage of cells populations and the parameters of phagocytosis by neutrophils and monocytes of Staphylococcus aureus were determined in the blood. The Thymus and Spleen were weighed and made smears-imprints for counting Thymocytogram and Splenocytogram. Results. It was established that males have significantly higher levels of 11 variables: serum testosterone and triiodothyronine, percentage of epitheliocytes, endotheliocytes, and macrophages in the thymocytogram and its entropy, percentage of lymphocytes and lymphoblasts in the splenocytogram, phagocytosis activity of blood microphages and macrophages, as well as percentage of 0-Lymphocytes. On the other hand, females have significantly higher levels of 19 variables: serum corticosterone, catecholamines, PTH, calcitonin, aldosterone, the mass of the adrenal glands and the thickness of their fascicular, reticular and glomerular zones, the percentage of lymphocytes and lymphoblasts in the thymocytogram, fibroblasts in the splenocytogram and its entropy, natural killers and B-Lymphocytes in the immunocytogram of blood and its entropy, intensity of phagocytosis of macrophages as well as reaction of blast transformation of T-Lymphocytes to phytohemagglutinin. Using the method of discriminant analysis, 14 of the listed variables were selected as specific endocrine-immune markers of sex. Conclusion. Intact rats show pronounced sexual dimorphism in a number of indicators of the endocrine and immune systems, which can be assessed quantitatively by the Mahalanobis distance (D² = 2620), indicating a very large inter-group separation, and by the difference between the discriminant roots (51.2), reflecting the magnitude of between-sex variance explained by the selected variables. This approach will make it possible to quantitatively assess the influence of stressors and adaptogens on sexual endocrine-immune dimorphism in subsequent studies.
Keywords: adaptation hormones, HRV, adrenal glands, thymus, spleen, immunocytes of blood, phagocytosis, male and female rats
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