Relationships between Thyroid Hormones, Blood Rheology, and Lipid Profile in Athletes

The interrelation of thyroid hormones with blood rheology and lipid profile was studied in athletes (N = 12). A decrease in blood viscosity in the athletes was caused by a lower erythrocyte rigidity index, which correlated with an increased reticulocyte count (P = 0.022), a decreased mean concentration of hemoglobin per cell (MCHC) (P = 0.006), and an increased level of thyrotropin (TTH) (P = 0.040). By multiple regression analysis, MCHC was found to be the primary correlate of the erythrocyte rigidity index (P = 0.044). The interrelation of TTH with the rigidity index was explained by a positive correlation of TTH with the reticulocyte count (P = 0.022). The level of triiodothyronine (T₃) was similar in the athletes and the control subjects and negatively correlated with total cholesterol (Ch) (P = 0.033) and low-density lipoprotein cholesterol (LDL Ch) (P = 0.048), which both correlated positively with blood and plasma viscosity and erythrocyte aggregation (P < 0.05 or 0.01). Thus, the decrease in LDL Ch in the athletes, which was closely related with the higher blood and plasma fluidities and with erythrocyte aggregation, was at least partly due to the effect of T₃.     

The pumping function of the heart in athletic tourists during a PWC<Subscript>170</Subscript> exercise

Changes in the pumping function of the heart (cardiac output) were studied in athletic tourists and untrained subjects during a PWC₁₇₀ test. It was confirmed that regular training remarkably improves the pumping function of the heart. At rest and during the PWC₁₇₀ test, the athletes exhibited more pronounced changes in the cardiac output than their untrained counterparts.     

Integration of Functional,Psychophysiological, and Biochemical Processes in Athletes after Audiovisual Stimulation

We studied intra- and inter-system structural interactions between functional, psychophysiological, and biochemical processes in athletes after audiovisual stimulation (AVS). We used multiple linear regression and correlation analysis after AVS to investigate the formation of new relations between the nervous, hormonal, cardiorespiratory, and metabolic systems. AVS training leads to an increase in physical working capacity (PWC₁₇₀) and in the number of its correlations, e.g., with the amplitude of alpha-rhythm, resting heart rate (HR), concentrations of thyroxine, phosphorus, glucose, bilirubin, and triglycerides, antioxidant status, and the level of life satisfaction, which indicates the elevation in inter-system integration processes at different functional levels. An increase in the number and effects of factors contributing to PWC₁₇₀ (chronoinotropic reserve, lung capacity, reaction of individual α-rate power depth, reaction to the moving object, and the concentrations of glucose, creatinine, bilirubin, and thyroxine) eventually resulted in higher PWC₁₇₀. This indicates that the rate of synchronization between the studied parameters increases under the influence of sensory impact, which results in the improvement of adaptive capacity and provides a lower cost of adaptation to physical loads at the competitive stage of sports training.     

Analysis of the Relationship Between Hemorheologic Parameters,Aluminum, Manganese,and Selenium in Smokers

Smoking is a significant risk factor in fatal pathologies including cardio-cerebrovascular and respiratory diseases. Aluminum (Al) is a toxic element without known biological function, but with recognized toxic effects. Manganese (Mn) and selenium (Se) are essential trace elements involved in cellular antioxidant defense mechanisms. Al, Mn, and Se carry out their metabolic activities via blood flow and tissue oxygenation. The structure and number of red blood cells (RBC) play important role in tissue oxygenation throughout blood flow. Increased hematocrit (Hct) as a result of probable hypoxia induces disturbed blood flow, RBC aggregation (RBC Agg), RBC deformability index (Tk), and oxygen delivery index (ODI). Therefore, we aimed to investigate the effects of altered Al, Mn, and Se levels on number, structure, and function of RBCs (Hct, blood and plasma viscosity (BV and PV, respectively), RBC Agg, Tk, ODI) in smokers without diagnosis of chronic obstructive pulmonary disease (COPD) in a study group (n = 128) categorized as ex-smokers (ES), smokers (S), and healthy controls (HC). Elements were analyzed in serum using ICP-OES. BV and PV were measured via Brookfield and Harkness viscometers at 37 °C, respectively. Smokers had statistically higher serum Al and Mn levels, BV, RBC, Hgb, Hct, PV, fibrinogen, RBC Agg, Tk₄₅, and pulmonary blood flow rate, but lower serum Se levels and ODI₄₅ values versus HC. In conclusion, increased Al, Mn, and hemorheological parameters and decreased Se and ODI₄₅ might result from inflammatory response in defense mechanism in smokers without diagnosis of COPD. Our results point out that serum Al, Mn, and Se with hemorheological parameters may be beneficial markers of tissue oxygenation and defense mechanism before the clinic onset of COPD in smokers.

     

Age-related changes of plasma steroids in normal adult males

Plasma cortisol, 17-hydroxyprogesterone (17-OH-P), testosterone (T), 5α-dihydrotestosterone (DHT, estrone (E₁) and estradiol (E₂), were measured in 94 normal adult men aged between 20–99. using RIA methods after chromatographic separation of steroids on Sephadex LH-20 columns.All plasma steroids except 17-OH-P, were age dependent: cortisol, testosterone and DHT decreased significantly with age, whereas estrone and estradiol were significantly increased in elderly men. Cortisol, testosterone. T/DHT ratio and estradiol levels were significantly correlated with age.The age related changes of plasma steroids in elderly men, were suggestive of decreased cortisol secretion, and decreased testicular function with increased peripheral conversion of androgens into estrogens. Testosterone was positively correlated with its precursor (17-OH-P) and respectively its peripheral metabolites (DHT and E₂). The negative correlation between estrone and 17-OH-P found in elderly men, suggested that increased estrogen level in aging males may be considered able to inhibit the testicular androgen production.     

Postural stability during static strain before and after a submaximal aerobic bicycle test in athletes

Control of static balance was studied in wrestlers (n = 31) in the normal state and against the background of physical fatigue, i.e., before and after a bicycle PWC ₁₇₀ test, respectively. The static balance was evaluated using a Ritm force platform (Russia) during normal basic stance (BS) and static strain (half-squatting position (HS) with the eyes open). Before physical exercise, i.e., during BS, the differences in postural control of the center of pressure (CP) between athletes and control subjects (n = 40) were nonsignificant. In the HS position, both linear and angular sway velocities of CP (LSV and ASV, respectively) were significantly lower in wrestlers (p < 0.001), and these parameters were negatively correlated with the PWC ₁₇₀ index (r = −0.454 and r = −455, p < 0.001 for LSV and ASV, respectively), which suggests that up to 20% of the sway velocity variance during static strain is dependent on the working capacity of the subjects. After the PWC ₁₇₀ test, the sway velocities of CP increased in both groups during BS (p < 0.01) and HS (p < 0.001), which testifies to the important role of muscular fatigue in the decrease in postural stability in both groups. During BS, an increase in LSV and ASV was about the same in both groups; however, during HS, an increase in the sway velocities of CP after PWC ₁₇₀ was lower in wrestlers (the intergroup differences at p = 0.037 and p = 0.008 for LSV and ASV, respectively); this parameter was negatively correlated with the recovery of the heart rate (HR) after the bicycle test (r = −0.378, p < 0.001 and r = −0.265, p < 0.05 for LSV and ASV, respectively), which suggests that rapid recovery contributes to a certain extent (about 6.5–14.2%) to the postural stability during static strain of wrestlers against the background of their physical fatigue.     

Seasonal changes of steroid levels in blood plasma of three phodopus species (Mammalia,Cricetinae)

Seasonal change of the base plasma level of testosterone and cortisol in males and progesterone, estradiol, and cortisol levels in females were analyzed in three Phodopus species: Ph. campbelli (Campbell’s hamster), Ph. sungorus (Djungarian hamster), and Ph. roborovskii (Roborovskii dwarf hamster). Our results showed a significant difference in the seasonal plasma level of testosterone and cortisol in males and cortisol in females of all Phodopus species, though the rhythms of breeding activity were similar. The results are discussed in the context of adaptive differences between hormonal patterns of more evolutionarily modern species (Campbell’s hamster and Djungarian hamster) and the more evolutionarily old Roborovskii dwarf hamster, the phylogenic position of which is currently under discussion.     

Diurnal patterns of testosterone, dihydrotestosterone, estradiol, and cortisol in serum of rhesus males: Relationship to sexual behavior in aging males

This study was carried out to determine differences between old and young rhesus males in levels and diurnal patterns of testosterone, dihydrotestosterone, cortisol, and estradiol, and to determine correlations between these hormones and sexual behavior of the old males. Blood was drawn from old (n = 9) and young (n = 9) rhesus males over 5 consecutive days at 0900, 1300, and 2100 hr. The two groups of males did not differ in mean serum levels of testosterone, dihydrotestosterone, or estradiol at any time. Although the old and young did not differ in cortisol levels at 0900 and 1300 hr, the cortisol levels at 2100 hr were lower in the old males. Diurnal variations in testosterone, dihydrotestosterone, and cortisol were comparable in old and young males. Mean serum levels of estradiol were significantly higher at 0900 hr than at 1300 hr in the old males, whereas in the young males estradiol levels did not differ with time of day. There was a significant positive correlation between testosterone and yawning rate, and cortisol levels were correlated positively with rate of contacting, rate of mounting, and percentage of tests with erections. The decline in sexual performance of old rhesus males cannot be attributed to changes in the levels or diurnal patterns of testosterone, dihydrotestosterone, or estradiol, but lower cortisol levels in old males may contribute to the decline in sexual behavior.     

Circannual rhythm of plasmatic vitamin D levels and the association with markers of psychophysical stress in a cohort of Italian professional soccer players

Adequate plasmatic Vitamin D levels are crucial to maintain calcium homeostasis and bone metabolism both in the general population and in athletes. Correct dietary supply and a regular sun exposure are fundamental for allowing the desired and effective fitness level. Past studies highlighted a scenario of Vitamin D insufficiency among professional soccer players in several countries, especially in North Europe, whilst a real deficiency in athletes is rare. The typical seasonal fluctuations of Vitamin D are wrongly described transversally in athletes belonging to teams that play at different latitudes and a chronobiologic approach studying the Vitamin D circannual rhythm in soccer players has not been described yet. Therefore, we studied plasma vitamin D, cortisol, testosterone, and creatin kinase (CK) concentrations in three different Italian professional teams training at the same latitude during a period of two consecutive competitive seasons (2013 and 2014). In this retrospective observational study, 167 professional soccer players were recruited (mean age at sampling 25.1 ± 4.7 years) and a total of 667 blood drawings were carried out to determine plasma 25(OH)D, serum cortisol, serum testosterone and CK levels. Testosterone to cortisol ratio (TC) was calculated based as a surrogate marker of overtraining and psychophysical stress and each athlete was drawn until a maximum of 5 times per season. Data extracted by a subgroup of players that underwent at least 4 sample drawings along a year (N = 45) were processed with the single and population mean cosinor tests to evaluate the presence of circannual rhythms: the amplitude (A), acrophase (Φ) and the MESOR (M) are described. In total, 55 players (32.9%) had an insufficient level of 25(OH)D during the seasons and other 15 athletes (9.0%) showed, at least once, a deficiency status of Vitamin D. The rhythmometric analyses applied to the data of Vitamin D revealed the presence of a significant circannual rhythm (p < 0.001) with the acrophase that occurred in August; the rhythms of Vitamin D levels were not different neither among the three soccer teams nor between competitive seasons. Cortisol, testosterone and TC showed significant circannual rhythms (p < 0.001): cortisol registered an acrophase during winter (February) while testosterone and TC registered their peaks in the summer months (July). On the contrary, CK did not display any seasonal fluctuations. In addition, we observed weak but significant correlations between 25(OH)D versus testosterone (r = 0.29 and p < 0.001), cortisol (r = ?0.27 and p < 0.001) and TC (r = 0.37 and p < 0.001). No correlation was detected between Vitamin D and CK. In conclusion, the correct chronobiologic approach in the study of annual variations of Vitamin D, cortisol and testosterone could be decisive in the development of more specific supplementation and injury prevention strategies by athletic trainers and physicians.     

Pulmonary blood volume and interventricular circulation time in physically trained and untrained subjects.

Resting pulmonary plasma and blood volumes (PPV and PBV), interventricular circulation time (IVCT), cardiac and stroke index (CI and SI), heart rate (HR), total plasma and blood volumes (PV and BV) were determined in athletes (two male groups representing different types of sport activities, and one female group) and compared with those of non-athletes (one male and one female group). In addition to high maximal aerobic power, the athletes were characterized by greater SI, BV and PV and lower resting HR than non-athletes, PPV and PBV were significantly larger and IVCT significantly longer in the trained than in the untrained groups, probably reflecting an improved capacity of the pulmonary circulation. PPV as per cent of PV was almost equal in all the groups, indicating the same distribution of plasma between the pulmonary and systemic circulation. The data also indicate that total blood volume is an important determinant of the magnitude of the pulmonary vascular bed. The increased volume of flowing blood and increased stroke volume in athletes probably allows for a reduction in flow velocity and thereby a reduction in kinetic energy.     

The effects of cortisol and testosterone on renal function in male Antechinus stuartii (Marsupialia)

Seasonal changes in the physiology of Antechinus stuartii result in complete male mortality after mating. The most important endocrine changes in males are large rises in plasma testosterone and cortisol concentrations. Glomerular filtration rate (GFR) in males declines coincident with high plasma testosterone and cortisol. In the present study GFRs were measured in males captured in May (when endogenous plasma testosterone and cortisol levels are low) and given depot injections of either saline, testosterone-only, cortisol-only or testosterone plus cortisol at doses designed to mimic plasma levels during the mating period. GFR decreased significantly with testosterone injection, independent of cortisol treatment. Urinary concentrations of sodium and chloride, and osmolality decreased significantly with cortisol treatment, although the addition of testosterone reversed the effect. Total urinary excretion of electrolytes was similar between groups. Plasma potassium levels significantly increased in testosterone plus cortisol treated males. Plasma sodium levels significantly increased and plasma chloride significantly decreased in all groups treated with cortisol. Water consumption significantly increased in all cortisol-treated males and food consumption significantly increased in all testosterone-treated males. The seasonal renal functional changes observed in A. stuartii were mimicked by testosterone administration. Accepted: 23 January 1998     

A recognition system for sex-hormone-binding protein-estradiol complex in human decidual endometrium plasma membranes

We have studied the specific binding of human serum sex-hormone-binding protein and its complexes with estradiol and testosterone to an enriched membrane fraction isolated from human decidual endometrium. The specific binding of sex-hormone-binding protein to these membranes has been found to be dependent on it being bound with estradiol. When estradiol concentration in the medium is high enough to provide for the saturation of sex-hormone-binding protein with the steroid, the protein exhibits specific binding to the membranes with an apparent equilibrium constant, K_d = (3.5 ± 2.0) · 10⁻¹² M. In the absence of estradiol, the binding protein devoid of steroid or complexed with testosterone does not interact with the membranes. At low concentrations of sex-hormone-binding protein and estradiol, when their complex is almost completely dissociated in solution, it can be reconstituted on the membranes with the optimum estradiol to binding protein ratio being 1:1 (mol/mol). It is proposed that, in plasma membranes of the estradiol target cells, there is a recognition system for the sex-hormone-binding protein-estradiol complex which may allow these cells to take up from blood not only free estradiol, but also estradiol complexed with the binding protein.     

Plasma leptin levels of elite endurance runners after heavy endurance training

A decrease in testosterone levels and an increase in cortisol levels are observed in male athletes with the overtraining syndrome (OTS). Cortisol causes blood leptin levels to rise and testosterone has an inverse relationship with blood leptin levels. Therefore, we hypothesized that the hormonal changes as a result of OTS induce an increase in leptin. To test this hypothesis, we examined the relationship among changes in leptin, testosterone and cortisol in thirteen male collegiate distance runners (aged 20.3+/-1.1 years) before and after an 8-day strenuous training camp. Runners ran 284.1+/-48.2 km during the training camp. Body fat percentages and plasma glucose concentrations decreased significantly after the training. Non-ester fatty acids and total cholesterol concentrations in blood were unchanged. Serum cortisol concentrations showed a significant increase after the training camp (from 11.82+/-2.00 microg/dl to 16.78+/-3.99 microg/dl), and serum testosterone decreased significantly (from 408.0+/-127.6 ng/dl to 265.2+/-97.6 ng/dl). The ratio of testosterone to cortisol (TCR) dropped by 50% after training (from 35.62+/-13.69 to 16.94+/-8.47). These results suggest that the subjects reached a state of the OTS. Contrary to our hypothesis, plasma leptin was not significantly changed (from 1.34+/-0.29 ng/ml to 1.49+/-0.18 ng/ml). Delta Plasma leptin was not significantly correlated with delta serum cortisol, delta TCR or delta fat percentage. However, delta serum testosterone was positively correlated with delta plasma leptin (r=596, p<0.05). Plasma leptin concentrations might modulate the secretion of testosterone in overtraining conditions. In conclusion, the change in blood leptin level is independent of the changes in cortisol, TCR and fat percentage in highly trained male athletes in the state of the OTS.     

Endocrine changes during the previtellogenic stage of the great sturgeon,Huso huso (Linnaeus, 1758)

The study aimed to investigate changes in serum concentrations of sex steroids, thyroid hormones, stress indices, cholesterol, triacylglycerol, calcium and phosphorus, as well as the growth in the 3‐year old previtellogenic stage of great sturgeon, Huso huso over a 6‐month period. Forty individually marked fish (mean weight 6913 g) were divided among three circular tanks under a natural temperature and photoperiod. Every 1.5 months fish were weighed and blood samples taken for serum analysis. Fish showed significant changes in 17β estradiol, testosterone, triiodothyronine (T₃), thyroxine (T₄), adrenocorticotropic hormone, cortisol, cholesterol, and phosphorus, but not in triacylglycerol and calcium concentrations. From the January onset of the experiment to the end of the trial in July, there was a decrease in sex steroids and cortisol concentrations as well as a decline in T₃ concentrations from March and in T₄ from February to July. The mean weight of fish increased significantly from the beginning to the end of the experiment. Although the oocyte diameter increased from 197 to 202 μm, the difference was not significant. The histological data on oocytes suggest that the great sturgeon, like the other sturgeons, has a heterogeneous asynchronous ovarian development in the early stage of reproduction. This data might be useful to the further understanding of the physiology of Huso huso and/or to improve its culture. Moreover, it leads to a general increase in the understanding of the basic reproductive biology of this valuable chondrostean species.     

Nitric oxide scavenging by cell-free hemoglobin may be a primary factor determining hypertension in polycythemic patients

Abstract

We tested the hypothesis that hypertension associated with polycythemia vera (PV) may be related to hemoglobin released from erythrocytes (cell-free hemoglobin, fHb). We assessed hematocrit, mean arterial pressure (MAP), blood viscosity, and the level of fHb and nitrite/nitrate (NO_x) in the plasma of 73 PV patients and 38 healthy controls. The effect of isovolemic erythrocytapheresis (ECP) on the considered parameters was also studied. From the whole group of PV patients a subset of subjects with normal (normotensive patients, n = 16) and elevated MAP (hypertensive patients, n = 57) can be subtracted.

It was found that in comparison with healthy controls, PV patients have significantly (p ≤ 0.01) elevated Hct (0.567 vs. 0.422), blood viscosity (5.45 vs. 3.56 cP), MAP (106.8 vs. 93.8 mmHg), plasma fHb (9.7 vs. 2.8 mg/dL), and NO_x levels (34.1 vs. 27.5 μM). Compared with normotensive patients, hypertensive PV patients demonstrated a higher rise in fHb (10.2 vs. 8.0) and plasma NO_x levels (35.8 vs. 31.0). In PV patients, fHb positively correlates with MAP (r = 0.489), NO_x levels (r = 0.461), hematocrit (r = 0.428), and viscosity (r = 0.393). Blood viscosity positively correlated with hematocrit (r = 0.894), but not with other considered parameters. In PV patients MAP poorly correlated with hematocrit, whereas the correlation between MAP and NO_x altered from ? 0.325 (healthy control) to + 0.268 (PV patients). ECP procedure was associated with a significant (p < 0.01) reduction of hematocrit, fHb, blood viscosity, and MAP. In the normotensive subgroup of PV patients the ECP procedure did not affect MAP. It can be concluded that accelerated scavenging of nitric oxide by fHb rather than high Hct may be a key factor determining the development of hypertension in PV patients.     

The effect of the administration of spironolactone on the concentration of plasma testosterone,estradiol and cortisol in male dogs

The effect of the administration of spironolactone, deacetylspironolactone, aldadiene or soldactone on the concentration of plasma testosterone, estradiol, and cortisol was examined in male dogs. Decreases of 60 to 75% in plasma testosterone and estradiol occur only at high doses (100 mg/kg) of spironolactone or deacetylspironolactone but not at low doses of spironolactone (5 to 10 mg/kg); they occur concomitantly with similar decreases of androgen formation by the testis. No decreases were detected with aldadiene or soldactone. Treatment of dogs with spironolactone (100 mg/kg) also lowered by 50 to 65% the concentration of cortisol in adrenal venous plasma.     

Association between Myocardial Triglyceride Content and Cardiac Function in Healthy Subjects and Endurance Athletes

Ectopic fat accumulation plays important roles in various metabolic disorders and cardiovascular diseases. Recent studies reported that myocardial triglyceride (TG) content measured by proton magnetic resonance spectroscopy (¹H-MRS) is associated with aging, diabetes mellitus, and cardiac dysfunction. However, myocardial TG content in athletes has not yet been investigated. We performed ¹H-MRS and cardiac magnetic resonance imaging in 10 male endurance athletes and 15 healthy male controls. Serum markers and other clinical parameters including arterial stiffness were measured. Cardiopulmonary exercise testing was also performed. There were no significant differences in clinical characteristics including age, anthropometric parameters, blood test results, or arterial stiffness between the two groups. Peak oxygen uptakes, end–diastolic volume (EDV), end–systolic volume (ESV), left ventricular (LV) mass, peak ejection rates and peak filling rates were significantly higher in the athlete group than in the control group (all P<0.02). Myocardial TG content was significantly lower in the athlete group than in the control group (0.60±0.20 vs. 0.89±0.41%, P<0.05). Myocardial TG content was negatively correlated with EDV (r = −0.47), ESV (r = −0.64), LV mass (r = −0.44), and epicardial fat volume (r = 0.47) (all P<0.05). In conclusion, lower levels of myocardial TG content were observed in endurance athletes and were associated with morphological changes related to physiological LV alteration in athletes, suggesting that metabolic imaging for measurement of myocardial TG content by ¹H-MRS may be a useful technique for noninvasively assessing the “athlete’s heart”.     

Effect of blood volume on plasma volume shift during exercise

To assess the relationship between blood volume (BV) and the reduction in plasma volume (PV) during exercise in individual variations, we measured BV and changes in PV in thirteen male volunteers during treadmill exercise until exhaustion. The lactate threshold (LT), as a predictor of aerobic exercise capacity, was calculated from the exercise intensity at the point of plasma lactate concentration buildup to 4 mmol. The relationship of peak VO₂ with BV indicated a significant positive correlation. The strong positive relation between the shifts in PV and total PV, and resulted in a maintenance of the circulating BV.