Elsevier

Life Sciences

Volume 61, Issue 3, 13 June 1997, Pages 301-308
Life Sciences

GLUCOCORTICOID RECEPTORS IN HUMAN PERIPHERAL BLOOD MONONUCLEAR CELLS IN RELATION TO AGE AND TO SPORT ACTIVITY

https://doi.org/10.1016/S0024-3205(97)00386-XGet rights and content

Abstract

Glucocorticoid receptors (GR) are ubiquitous molecules and are present also in the hippocampus and in several other nervous and immune tissues. Peripheral blood mononuclear cells (PBMCs) are a good model for studies of GR in humans. Glucocorticoids are important for maintaining cellular and humoral homeostasis and are key mediators of neuroendocrine-immune regulatory interactions. The increase of cortisol is immunosuppressive and reduces GR concentration both in nervous and immune systems. Variation of glucocorticoids in healthy aged subjects and athletes has been shown. Prompted by these results, we have investigated in man a possible relationship between GR binding capacity in the PBMCs and age, in relation also to plasma testosterone and cortisol. The same parameters have been examined in a group of soccer players for comparison with the sedentary group. GR binding capacity was higher in younger subjects than in older ones, and lower in the group of athletes than in the younger and older sedentary subjects. In the sedentary group a negative correlation was present between GR binding capacity and age. Plasma cortisol was higher and testosterone lower in the athletes; they were negatively correlated in athletes and positively correlated in the sedentary subjects. The results for athletes agree with their lower anabolic/catabolic balance. The mechanism of reduced GR levels in relation to age and sport activity could involve a loss or an involution of receptor synthesis. However other possibilities, such as altered distribution of lymphocyte subpopulations with different receptor concentrations and with different cytokine production, cannot be excluded. Several neuroendocrine-immune interactions could be responsible for reduced GR levels with age and sport activity in man.

Section snippets

Materials and Methods

Subjects: For this study three groups have been considered. Athletes (n = 15): soccer players (age range 19–29 yr; mean ± SD: 23 ± 3) belonging to a semi-professional team. The training program of the team consisted of one daily training session (90–120 minutes) 4 times a week with one competition on Sundays. The training program consisted of aerobic (endurance running) and anaerobic (intense short-distance running) exercise. The athletes were not on a particular dietary regimen. Younger

Results

Saturation curves and Scatchard plots obtained in the athletes and sedentary group are shown in Fig. 1. Maximum binding was obtained in both conditions. The slopes of Scatchard plots are very similar although the binding capacity is lower in the athletes. The binding affinity (Kd = 5.05 ± 0.79) did not vary between groups. Values of binding capacity of GR in PBMCs from soccer players, younger sedentary and older sedentary subjects are indicated in Fig. 2. In the sedentary subjects, there were

Discussion

In line with previous research 2, 22, 23, the present study demonstrates a significant age-related decrease of GR binding capacity in PBMCs from normal human subjects. Plasma cortisol concentrations did not change with age, in agreement with other reports 22, 23, 24, even if older subjects tended to have lower values. The presence of normal plasma cortisol in older subjects suggests a loss of receptors with aging. Another work shows a GR reduction with increased plasma cortisol concentrations

Acknowledgements

We thank Dr. G.F. Bolelli (Department of Obstetrics and Gynecology, University of Bologna, Italy) for the anticortisol and antitestosterone antisera and Mr. P. Migliaccio for his excellent technical assistance. This work was financed by 40% and 60% funds from MURST, Rome.

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