The influence of thyroid function and bone turnover on lipoprotein profile in young physically active men with different insulin sensitivity.

Physical activity induces changes in the endocrine system. Previous data indicated that changes in insulin secretion and the tissue response to this hormone are very important for energy metabolism. It is believed that they are accompanied by changes in lipid metabolism, but factors contributing to this process are still disputed. The aim of this study was to assess interactions among insulin sensitivity, thyroid function, a bone turnover marker and serum lipid profile in young physically active men. Eighty-seven physical education students, aged 18-23 years, participated in the study. We measured serum levels of glucose, lipids, insulin, thyroid-stimulating hormone (TSH), osteocalcin and anthropometric parameters. Insulin sensitivity was determined using homeostatic model assessment for insulin resistance (HOMA-IR). The median value of HOMA-IR (1.344) was used to divide the study population into Group A (above the median) and Group B (below the median). Men from both groups did not differ in anthropometric parameters or in daily physical activity. Triglycerides (TG), total cholesterol (TC) and high-density lipoprotein cholesterol (HDL-C) levels were higher in Group A (P < 0.05). TSH and osteocalcin levels were similar in males with different HOMA-IR. Multiple regression analysis for TSH and osteocalcin showed that in Group A these hormones had no effect on plasma lipoproteins. However, in Group B they significantly determined the variation of plasma TC and low-density lipoprotein cholesterol (LDL-C) levels (in about 28% and 29%, respectively). We concluded that TSH and osteocalcin are involved in determination of a more healthy lipid profile at a certain level of insulin sensitivity.

Gender differences in carotid artery intima-media thickness and flow-mediated dilatation in young, physically active adults.

AIM: The purpose of this study was to examine gender differences (GD) in vascular structure and function and their relations to cardiovascular risk factors (CVD) in young, physically active adults. METHODS: Sixty-three apparently healthy, physically active adults (34 women, 29 men), aged 20.2±0.9 years, were involved in the study. RESULTS: Carotid artery intima-media thickness (IMT) values of both internal carotid (CI) and common carotid arteries (CC) were significantly (P<0.01 and P<0.01) higher in men than in women (0.47±0.05 vs. 0.51±0.07 mm and 0.45±0.07 vs. 0.49±0.07 mm, respectively). In women, CC-IMT was positively correlated with body fat mass, height and body mass; and CI-IMT was inversely correlated with systolic and diastolic blood pressure. In men, CI-IMT was positively correlated with body height, diastolic blood pressure and high sensitivity C-reactive protein (hsCRP). Relative values of flow-mediated dilatation (FMD) increased in women by 16.6%, in men by 13.7% after a 5-minute period of forearm ischemia, but absolute FMD was similar in men and women, 0.53±0.25 vs. 0.53±0.14 mm, respectively. CONCLUSION: Values of CC IMT and CI IMT after adjustment to classical CVD risk factors remained strongly diversified with respect to gender, which confirmed the significance of gender as a conditional factor for atherosclerosis assessment. Some GD in vascular structure and function could be eliminated by adjusting for baseline artery diameter and/or subject's somatic features, i.e., body height. This study supports a need for additional studies focusing on understanding GD in vascular characteristics, which could lead to established better quality reference values and comprehend natural history of CVD in view of pathophysiological mechanisms underlying GD.

Plasma proinsulin, C-peptide and sex hormone concentrations in regularly menstruating premenopausal females with ovulatory and anovulatory menstrual cycles.

AIM: Highly active females are at risk of athletic menstrual irregularities including anovulatory menstrual cycles, oligomenorrhea and even amenorrhea. On the other hand, the functional relationship between endocrine pancreas and ovaries is supported by numerous studies indicating that disturbed female sex hormone secretion coexists with insulin resistance and glucose intolerance. However, the relationship between circulating beta islet and ovarian hormones in regularly menstruating active women with ovulatory and anovulatory menstrual cycle has not been studied. METHODS: A total of 32 regularly menstruating women participated in the study. Prospective subjects monitored their BBT for 3 months before the study. The determination of plasma progesterone levels between days 5-8 and again between days 19-22 of the menstrual cycles made possible the classification of subjects as ovulating or non-ovulating. Plasma 17-beta-estradiol, testosterone, insulin, proinsulin, C-peptide and glucose concentrations were assayed on the same menstrual cycle days as progesterone. RESULTS: There were no differences in circulating insulin, C-peptide and glucose between non-ovulating and ovulating women. In contrast, in non-ovulating subjects plasma proinsulin concentrations between days 19-22 were slightly, but significantly higher than between days 5-8 of the menstrual cycle (P<0.05). Exclusively in non-ovulating women significant and positive correlation was noted between circulating proinsulin and 17-beta-estradiol in data collected from both days 5-8 and 19-22 of the menstrual cycle (P<0.008). CONCLUSIONS: Our results indicate that in the face of low circulating progesterone and subsequent anovulation circulating 17-beta-estradiol slightly, but significantly, affect either pancreatic beta-cell biosynthetic activity or proinsulin hepatic and/or renal clearance.

Plasma leptin concentrations in lean, physically active males and females in relation to body composition and metabolic variables.

AIM: It is well recognized that plasma leptin levels even adjusted to body fat are significantly higher in females than in males. Additionally, physical activity irrespectively of sex is known to affect plasma leptin concentrations. However, the predictors of plasma leptin levels in males and females characterized by similar physical activity were not studied. The aim of the present study was to examine the predictors of plasma leptin concentrations in male and female physical education students not engaged in any specific sport but active due to obligatory studies' program. METHODS: A total of 36 subjects (17 males and 19 females) volunteered to participate in the study. Fasting blood was drawn from the antecubital vein for glucose and insulin determination. Fasting insulin resistance index (FIRI) was calculated from insulin and glucose plasma levels. Body fat was assessed using bioelectric impendance method (BIA). Pearson product-moment correlations between log10 transformed plasma leptin concentrations and FIRI, fat mass, percentage of body fat and lean body mass were calculated. Multiple regression analysis was performed to find the best model predicting plasma leptin levels. RESULTS: In males the only variables affecting plasma leptin concentrations were fat mass (r=0.60; p<0.01) and and the percentage of body fat (r=0.49; p<0.04). In contrast, in females the best model included fat mass, lean body mass and FIRI (adj. R2=0.538; p=0.002). CONCLUSION: The results of the current study indicated that the predictors of plasma leptin levels markedly differed in physically active males and females. The only variable predicting plasma leptin concentrations in both males and females was body fatness. In females lean body mass and fasting insulin resistance index (FIRI) together with body fatness markedly contributed to the variations in plasma leptin concentrations.

Anaerobic performance of arms and legs in male and female free style wrestlers.

The aim of the present study was to compare arm and leg anaerobic peak and mean power after normalisation for body mass (W/kg) and fat-free mass (W/kg FFM) of 12 female and 10 male wrestlers, members of the Polish Olympic team. Power outputs were assessed by 30 seconds leg cycling and 30 seconds arm cranking. It was determined that males had higher peak power (11.4 W/kg and 13.2 W/kg FFM for legs, 9.6 W/kg and 11.2 W/kg FFM for arms) as well as mean power (8.7 W/kg and 9.6 W/kg FFM for legs, 6.9 W/kg and 7.9 W/kg FFM for arms) than females (peak power 8.6 W/kg and 11.3 W/kg FFM for legs, and 5.9 W/kg, 7.8 W/kg FFM for arms, mean power 6.8 W/kg, 9.0 W/kg FFM for legs and 5.9 W/kg, 7.8 W/kg FFM for arms). Post-exercise maximal blood lactate concentration after 30 seconds leg cycling and 30 seconds arm cranking was also higher in male wrestlers (11.9 and 11.8 mmol/l, respectively) than in female wrestlers (10.4 and 9.1 mmol/l, respectively). However the ratios of lactate concentration to mean power expressed in W/kg FFM for males and females in leg cycling (1.18 and 1.17, respectively) and in arm cranking (1.48 and 1.50, respectively) were similar. These findings suggest that the amount of energy derived from glycolysis is not sex-dependent. Additionally it seems that the higher ratios for arms when compared to legs reflect closer relation of arm muscle energy metabolism to carbohydrate utilisation.

Plasma insulin and glucagon concentrations and biochemical variables in regularly menstruating females with ovulatory and anovulatory menstrual cycles.

Ovarian hormones are known to affect endocrine pancreas function. However, data concerning the effects of anovulatory menstrual cycles in regularly menstruating women on endocrine pancreas and blood metabolites are lacking. We examined plasma insulin, glucagon, glucose, lactate, urea and glycerol concentrations in reproductive-age, regularly menstruating females classified as ovulating or non-ovulating on the basis of basal body temperature measurements and plasma 17beta-estradiol and progesterone determinations. All measurements were performed twice--in the follicular and again in the luteal phases of the menstrual cycle. There were no differences in plasma lactate and glycerol concentrations between the two groups of subjects. Plasma insulin concentrations tended to be lower in non-ovulating than in ovulating women. In addition, plasma glucagon did not differ in the follicular (33.2 pmol/l) or luteal phase of the menstrual cycle in females with disturbed ovarian hormone secretion (34.1 pmol/l). In contrast, plasma glucagon concentrations in the luteal phase (32.8 pmol/l) were significantly higher than in the follicular phase (24.9 pmol/l) of the menstrual cycle in ovulating women. Plasma glucose concentrations in the follicular phase of the menstrual cycle in non-ovulating women (4.1 mmol/l) were slightly but significantly lower than in their ovulating counterparts (5.3 mmol/l). Furthermore, no correlations were noted between plasma glucose and insulin-to-glucagon molar ratio in non-ovulating subjects. Plasma urea concentrations in non-ovulating women were markedly lower than in ovulating women in both follicular and luteal phases of the menstrual cycle (4.1 and 3.9 mmol/l vs. 5.3 and 5.4 mmol/l in non-ovulating and ovulating women, respectively). In ovulating women, plasma urea levels in both cycle phases were significantly correlated with plasma glucagon concentrations, but no such correlation was found in non-ovulating women. In conclusion, anovulatory menstrual cycles in premenopausal females slightly altered pancreatic hormone plasma levels but markedly impaired their action on plasma glucose and urea concentrations.

Plasma cortisol and testosterone following 19-km and 42-km kayak races.

Plasma cortisol and testosterone levels were examined in five, elite, male kayakers before and after 19-km and 42-km kayak races. Both races resulted in significant elevation in plasma cortisol and observed increase is likely to depend on race duration, being much more pronounced after 42-km race compared to 19-km. It should be stressed that observed elevation in cortisol level after 42-km race was higher than reported previously after a marathon run. This finding is in line with reports on hormonal changes in response to arms exercise. Both contests caused a decrease in plasma testosterone level, but the difference between races was not significant. Testosterone/cortisol ratio dropped significantly immediately after the races and the observed decrease was more dominant after the 42-km distance. On the next day, 18 h after the races plasma cortisol, testosterone levels and T/C ratio returned to basal level indicating recuperation from post exercise changes.

Plasma biochemical variables in response to 42-km kayak and canoe races.

Some plasma biochemical parameters were examined one day prior, immediately after and 18 h after 42-km canoe and kayak races. The increases in plasma glycerol, lactate, ammonia and uric acid as well as the elevation in plasma CK, LDH and transaminase activities confirm the changes induced by different prolonged efforts. However some differences between canoeists and kayakers were indicated for ammonia and urea plasma concentration after the race, lactate elimination and increase in CK and transaminase activities. The influence of body posture and the impact of the static component during effort are discussed as a reason for observed disparity in response to prolonged races.

[Effect of physical exercise on the fate of drugs in the body]. / Wplyw wysilku fizycznego na losy leków w organizmie.

A data from the literature on the effect of physical exercise on the fate of drugs in the body have been collected. An intensive exercise and training produce several important changes in the physiological and metabolic function of the tissues and organs, especially kidneys, liver and circulatory system. Therefore, absorption, metabolism, and elimination of numerous drugs are modified. An intensive physical exercise increases or decreases blood levels of drugs and effect their elimination. It should be stressed that the data on these problems are incomplete and related to various groups of drugs, different modes of application, and various models of exercise testing. It seems, however, that physical exercise should be considered and additional, besides genetic factors, diet or patient's age, factor affecting the fate of drugs in the body.

Creatine phosphate inhibition of heart 5'-nucleotidase appears due to contaminants.

Creatine phosphate does not inhibit 5'-nucleotidase preparations from rat, dog or guinea-pig hearts. Previously reported inhibitory effects must have been due to contaminants present in some commercial preparations of creatine phosphate.