The role of sex, adiposity, and gonadectomy in the regulation of irisin secretion.

A sexual dimorphism has been reported for the adipo-myokine irisin at rest and in response to exercise. The effects of male and female sex, adiposity, and gonadectomy on irisin secretion have not been investigated before. The objective of this study was to elucidate the effects of sex, adiposity, and gonadectomy in the regulation of irisin secretion as well as PGC-1α/FNDC5 mRNA and protein expression. We hypothesized that a lack of female sex hormones by ovariectomy reduces irisin levels and inhibits skeletal muscle expression of PGC-1α and FNDC5. Circulating irisin was measured in vivo in serum samples of healthy and obese men and women at rest and in response to acute exercise. The effects of gonadectomy on serum irisin, PGC-1α and FNDC5 muscle mRNA, and protein expression were investigated in ovariectomized (OVX) and orchiectomized (ORX) Wistar rats. Serum irisin at rest was not significantly different between men and women (lean or obese). However, in response to acute aerobic exercise, irisin levels increased significantly more in lean women versus men (p ≤ 0.05). In obese individuals, resting irisin concentrations were significantly higher compared to lean subjects (p ≤ 0.001) and the irisin response to acute exercise was blunted. Only the lack of gonadal hormones in OVX but not ORX rats increased serum irisin levels (p ≤ 0.01) and resulted in significantly increased body weight (p ≤ 0.01), adipose tissue content (p ≤ 0.05), muscle FNDC5 mRNA (p ≤ 0.05), and protein (p ≤ 0.01) expression without altering PGC-1α expression. Testosterone treatment in ORX rats leads to increased PGC-1α mRNA content and reduced PGC-1α protein content without affecting FDNC5 expression or serum irisin levels. We show that a sexual dimorphism exists for the acute irisin response to exercise in normal-weight but not in obese subjects. OVX, which is associated with increased adiposity and insulin insensitivity, increases basal FNDC5 expression and serum irisin, without altering PGC-1α expression. This may be an early sign for metabolic disturbances associated with menopause, such as a developing irisin resistance or an attempt of the organism to improve glucose metabolism.

ACE and ACTN3 genes polymorphisms among female Hungarian athletes in the aspect of sport disciplines.

The aim of the study was to determine the importance of two sport-associated gene polymorphisms, alpha-actinin-3 R577X (ACTN3) and angiotensin-converting enzyme I/D (ACE), among Hungarian athletes in different sports. The examination was carried out only on women (n = 100). Sport-specific groups were formed in order to guarantee the most homogeneous clusters. Human genomic DNA was isolated from blood, and genotyping was performed by polymerase chain reaction. To measure the differences between the participating groups, Chi-squared test was performed using Statistica 9.0 for Windows® (significance level: p < 0.05). In comparing the ACE I/D allele frequencies, significant difference was detected between water polo (I = 61.11%; D = 38.89%) and combat sports (I = 35.71%, D = 64.29%) athletes (p < 0.03). There was no statistical difference when ACE I/D alleles in combat sports and kayaking/rowing (p > 0.05) were compared. A similarity was detectable in the I allele frequencies of the water polo (61.11%) and kayaking/rowing (56.67%) groups. The ACTN3 R/X polymorphism showed no differences in comparison with the sport groups. R allele frequencies were higher in every group compared to the X allele. The potential significance of the ACE I allele in sports of an aerobic nature was not clearly confirmed among Hungarian athletes.

Retrospective Study of the Hungarian National Transplant Team's Cardiorespiratory Capacity.

The low availability of donor organs requires long-term successful transplantation as an accepted therapy for patients with end-stage renal and liver diseases. The health benefits of regular physical activity are well known among healthy individuals as well as patients under rehabilitation programs. Our aim was to describe the cardiorespiratory capacity of the Hungarian National Transplant Team. Twenty-five kidney (n = 21) or liver (n = 4) transplant athletes participated in this study. Maximal cardiorespiratory capacity (VO2max) was measured on a treadmill with the use of gas analysis. After a resting pulmonary function test, subjects completed a vita maxima test until exhaustion. Aerobic capacity of transplant athletes was higher than the age- and sex-predicted cardiorespiratory fitness (VO2max, 109.9 ± 21.7% of the predicted values; P = .0101). Resting respiratory function indicators exceeded 80% of predicted age- and sex-matched normal values. There were positive correlations between VO2max and workload (r(2) = 0.40; P = .0463), metabolic equivalent (r(2) = 0.72; P < .0001), and oxygen pulse (r(2) = 0.30; P = .0039). However, age showed negative correlation with VO2max (r(2) = 0.32; P = .0031), and there was no significant correlation between graft age and maximal oxygen consumption (r(2) = 0.15; P = .4561). Although the small amount of participants can not represent the general kidney and liver transplant population, the excellent cardiorespiratory performance suggests that a normal level of physical capacity is available after transplantation and can be even higher with regular physical activity. This favorable physiologic background leads to a state that provides proper graft oxygenization, which is an important factor in long-term graft survival.