Serum FSH, LH, and testosterone in humans after physical exercise

Influence of Long-Distance Bicycle Riding on Serum/Urinary Biomarkers of Prostate Cancer

Herein, we present a study focused on the determination of the influence of long-distance (53 km) bicycle riding on levels of chosen biochemical urinary and serum prostate cancer (PCa) biomarkers total prostate-specific antigen (tPSA), free PSA (fPSA) and sarcosine. Fourteen healthy participants with no evidence of prostate diseases, in the age range from 49-57 years with a median of 52 years, underwent physical exercise (mean race time of 150 ± 20 min, elevation increase of 472 m) and pre- and post-ride blood/urine sampling. It was found that bicycle riding resulted in elevated serum uric acid (p = 0.001, median 271.76 vs. 308.44 µmol/L pre- and post-ride, respectively), lactate (p = 0.01, median 2.98 vs. 4.8 mmol/L) and C-reactive protein (p = 0.01, 0.0-0.01 mg/L). It is noteworthy that our work supports the studies demonstrating an increased PSA after mechanical manipulation of the prostate. The subjects exhibited either significantly higher post-ride tPSA (p = 0.002, median 0.69 vs. 1.1 ng/mL pre- and post-ride, respectively) and fPSA (p = 0.028, median 0.25 vs. 0.35 ng/mL). Contrary to that, sarcosine levels were not significantly affected by physical exercise (p = 0.20, median 1.64 vs. 1.92 µmol/mL for serum sarcosine, and p = 0.15, median 0.02 µmol/mmol of creatinine vs. 0.01 µmol/mmol of creatinine for urinary sarcosine). Taken together, our pilot study provides the first evidence that the potential biomarker of PCa-sarcosine does not have a drawback by means of a bicycle riding-induced false positivity, as was shown in the case of PSA.

Effect of acute DHEA administration on free testosterone in middle-aged and young men following high-intensity interval training

With advancing age, plasma testosterone levels decline, with free testosterone levels declining more significantly than total testosterone. This fall is thought to underlie the development of physical and mental weakness that occurs with advancing age. In addition, vigorous exercise can also lower total and free testosterone levels with the decline greatest in physically untrained men. The purpose of the study was to evaluate the effect of oral DHEA supplementation, a testosterone precursor, on free testosterone in sedentary middle-aged men during recovery from a high-intensity interval training (HIIT) bout of exercise. A randomized, double-blind, placebo-controlled crossover study was conducted for 8 middle-aged participants (aged 49.3 ± 2.4 years) and an additional 8 young control participants (aged 21.4 ± 0.3 years). Each participant received DHEA (50 mg) and placebo on separate occasions one night (12 h) before a 5-session, 2-min cycling exercise (100% VO₂max). While no significant age difference in total testosterone was found, middle-aged participants exhibited significantly lower free testosterone and greater luteinizing hormone (LH) levels than the young control group. Oral DHEA supplementation increased circulating DHEA-S and free testosterone levels well above baseline in the middle-aged group, with no significant effect on total testosterone levels. Total testosterone and DHEA-S dropped significantly until 24 h after HIIT for both age groups, while free testosterone of DHEA-supplemented middle-aged men remained unaffected. These results demonstrate acute oral DHEA supplementation can elevate free testosterone levels in middle-aged men and prevent it from declining during HIIT. Therefore, DHEA supplementation may have significant benefits related to HIIT adaptation.

Different hormonal response to continuous and intermittent exercise in middle-distance and marathon runners

In order to study the effects of different athletic backgrounds on exercise-induced hormonal responses, serum testosterone, luteinizing hormone, follicle-stimulating hormone and cortisol concentrations were measured before and after intensive continuous and intermittent running in well-trained middle-distance runners (MID) and marathon runners (MAR). They performed two 40-min exercises on a treadmill: a continuous run at an intensity of 80% [tempo run (TR)] and an intermittent run (IR) at an intensity of 100% of the velocity associated with VO(2max). The testosterone response to IR and the cortisol response to TR was higher (P<0.05) in MID compared with MAR. The testosterone response to IR correlated positively with the maximal blood lactate concentration achieved after the maximal running test (r=0.46, P<0.05, n=20), while the cortisol response to TR correlated negatively with the runner's VO(2max) (r=-0.62, P<0.05, n=20). In conclusion, a continuous running exercise resulted in a lower cortisol response in runners who are adapted for longer distances, and an intermittent running exercise resulted in a higher testosterone response in runners who are adapted to middle distances.

Methodological and statistical considerations for exercise-related hormone evaluations

Improvements in laboratory techniques have allowed research related to exercise endocrinology to flourish. The emerging literature, however, is often inconsistent and contradictory. The discrepancies in research findings are possibly the result of poor control of confounding variables and/or inappropriate methodologies or analyses. Environmental and pretesting behavioural conditions must be standardised to minimise the influence of variables not directly related to the investigation. Environmental temperature and relative humidity, alcohol, caffeine and nicotine intake, prandial state, sleep deprivation and previous exercise can each alter hormonal responses to exercise. Both prescription and over-the-counter medications can also modify normal hormonal secretions thereby confusing exercise-induced findings. Specimen collection and analysis procedures must be controlled carefully. Changes in plasma volume related to postural changes or tourniquet-induced stasis can confound attempts to isolate exercise-related endocrine responses. The established circadian and rhythmical variations characteristic of many hormones need to be controlled. The specimen selection (plasma, serum, urine, etc), collection, storage and analysis procedures should be carefully planned and evaluated. The magnitude of haemolysis, analytical and biological variation must also be monitored. Isolating the hormonal perturbations resulting from a particular exercise variable can be very difficult. Exercise intensity, duration, mode, frequency and volume may each have specific effects on the endocrine changes seen with exercise and training. Furthermore, hormonal responses to exercise are dependent upon initial training status and fitness level. The statistical procedures and data presentation options selected to convey experimental findings can bias experimental results. The descriptive and inferential statistics to be used for data analysis should be preplanned and consistent with the underlying assumptions of the analytical procedure. Careful consideration should be given to the biological relevance of statistically significant findings. In some cases, data transformations (e.g. absolute vs relative changes, logarithmic) should be considered for analysis or presentation. Given the individual nature of hormonal responses to exercise, emphasis should be placed presenting individual data. Other considerations, including age, sex, racial origin and disease conditions need to be controlled for when trying to examine exercise-induced hormone changes.

Effects of follicular phase exercise on luteinizing hormone pulse characteristics in sedentary eumenorrhoeic women

OBJECTIVE

Current studies reveal little regarding the inception of exercise-induced LH changes during physical training. This study aimed to assess the susceptibility of the hypothalamic-pituitary axis to the acute physical stress of exercise in untrained, physically inactive women. The acute effects of submaximal endurance exercise upon the pulsatile LH secretion in the follicular phase were compared with those accompanying leisurely strolling for a similar time period.

SUBJECTS

All subjects were eumenorrhoeic, as determined by biphasic temperature patterns, detection of the urinary LH surge, and mid-luteal serum progesterone levels. Subjects were not physically active and had little history of strenuous exercise (VO2max = 38.0 +/- 1.8) (mean +/- SEM) ml/kg/min).

DESIGN

All women completed a 13.5-hour pulsatility test which included three consecutive 20-minute runs on a treadmill at 50, 60 and 70% of the subjects' maximum oxygen uptake (n = 16). Six of these same subjects completed a separate test on another occasion in which one hour of leisurely strolling was substituted for exercise. Blood was sampled every 10 minutes via an indwelling cannula for 4.5 hours before and 8 hours after one hour of exercise and or strolling.

MEASUREMENTS

A pulse algorithm (Pulsar) was used to quantify LH pulse characteristics.

RESULTS

Exercise produced no significant effects upon LH pulse frequency or mean serum LH concentration. However, exercise of moderate intensity caused a significant increase in LH pulse amplitude (P < 0.05). Strolling produced no significant changes in LH secretion.

CONCLUSION

Acute exercise of moderate intensity in the follicular phase of untrained women is an insufficient stimulus to inhibit the GnRH pulse generator in the post-exercise period, yet may produce a slight stimulatory effect on the amount of LH released per pulse.

Carbohydrate ingestion during prolonged running exercise results in an increase of serum cortisol and decrease of gonadotrophins

We tested the hypothesis that improved availability of energy through carbohydrate ingestion could counteract the documented suppression of pituitary-gonadal function during prolonged exercise. Nine trained males repeated twice a 36 kilometre running exercise with two weeks interval. During the tests the subjects ingested in a randomized single-blind fashion a total of 1050 millilitres of carbohydrate and placebo solutions. The total amount of ingested carbohydrate was 105 grams. Venous blood samples were taken before the exercise (sample A), immediately after exercise (B), and 2 hours later (C). In the B samples plasma glucose was 14% higher (P less than 0.01) and serum cortisol 13% higher (P less than 0.05) in the carbohydrate than in the control trial. In contrast, the level of LH was 18% (P less than 0.05) and that of FSH 11% lower (P less than 0.05) in the carbohydrate than in the placebo trial. Serum testosterone concentration did not differ between the treatment groups. We conclude that carbohydrate ingestion does not counteract the exercise-associated suppression of gonadotrophin secretion, but results in paradoxical increase of serum cortisol and decrease of LH and FSH, in comparison to placebo-treated controls. The higher cortisol level in carbohydrate group may be secondary to higher insulin levels.

Gonadotrophin-releasing hormone and human chorionic gonadotrophin tests reveal that both hypothalamic and testicular endocrine functions are suppressed during acute prolonged physical exercise

The mechanism of suppression of gonadotrophins and testosterone during prolonged exercise was studied. Fourteen healthy males were injected immediately before an exhaustive bicycle run for 4 h, and before a control period without exercise, with one of the following substances: (1) 1 ml of saline, (2) 100 micrograms of a GnRH agonist (buserelin), and (3) 50 IU/kg of hCG. Each test was repeated for each subject 2 weeks apart, in a randomized single-blind fashion. Blood samples were taken before the injections (sample A), 6 h after the injections (sample B), and the following morning (sample C). During placebo treatment testosterone concentration decreased from A samples to B samples more in the exercise trial than in rest trial (31 vs 8%, P = 0.02). This exercise-associated decrease was reversed by both the GnRH agonist and hCG treatments. Serum gonadotrophin concentrations responded identically to GnRH agonist injections during exercise and rest trials. hCG resulted in a greater increase of serum testosterone from A to C samples at rest than during the exercise trial (52 vs 33%, P = 0.04). In conclusion, the exercise-induced suppression of serum testosterone is associated with two effects: suppressed endogenous GnRH stimulation of gonadotrophin release during exercise, and decreased testicular capacity to secrete testosterone during recovery period.

Trait anxiety, submaximal physical exercise and blood androgens

This study evaluates the relationship between trait anxiety and both androgen and gonadotrophic hormone levels at rest and during severe physical exercise. Twelve volunteers were selected among 160 untrained male collegial students and classified as anxious (N = 6) or non-anxious (N = 6) subjects according to their scores on three trait-anxiety tests (STAI, IPAT, 16 PF). Serum delta 4-androgen (testosterone and delta 4-androstenedione), delta 5-androgen (DHEA and DHEA-SO4) and gonadotrophin (LH and FSH) concentrations were measured by radioimmunoassay before, during and after 20 minutes of intensive bicycle exercise (80% of maximal heart rate). Results indicate significantly lower serum delta 4-androgens in anxious subjects before exercise. However, for each subject and irrespective of his anxiety level, all measured serum androgen concentrations increased significantly during exercise, although delta 4-androstene-dione remained lower in anxious subjects than in non-anxious ones. Serum LH concentrations (but not FSH) were significantly higher in anxious subjects throughout the observation periods. However, exercise induced in each subject a significant decrease in the serum level of both gonadotrophic hormones. The results suggest that trait anxiety level may constitute an important factor that affects both pre-exercise and exercise serum androgen concentrations in untrained subjects.

A 7-week follow-up study of the behaviour of testosterone and cortisol during the competition period in rowers

Nine rowers (six men of the regional and three women of the national top class) participated in the study. During 7 consecutive weeks of the competition period serum testosterone (T), SHBG, cortisol (C) and urea were determined at the same time every morning under fasting conditions. From the concentrations of T and SHBG the free testosterone fraction (T/SHBG) was calculated, and from the concentrations of T and C the ratio of T/C was derived. The object of the investigation was to gather information on a potentially altered anabolic-catabolic hormone relationship dependent upon the intensity of the individual training periods. All rowers showed a continuous decrease in T, T/SHBG and T/C during the observation period. A week of regenerative training halted the decrease. In two of the oarsmen who discontinued their training after 2 and 3 weeks respectively, T, T/SHBG and T/C showed a normalization in the following weeks. In all subjects the concentrations of urea increased during the first 2 weeks and decreased during the subsequent weeks of intense training and competition. The findings suggest an increase in catabolic activity in periods of intensive physical strain, including competitions. Regenerative phases of training seem to reduce the anabolic-catabolic imbalance.

Early precursors of urogenital cancers in former college men

Physical and social characteristics recorded at college physical examination or reported at subsequent alumni questionnaire in 1962 or 1966 by 47,271 male former students from Harvard University and the University of Pennsylvania were reviewed for their relationship to risk for cancers of the kidney, bladder, prostate and testis. The records of 213 subjects who died with 1 of these cancers in a 16-50 year followup period and of 280 subjects who reported such a cancer by mail questionnaire in 1976 or 1977 were compared with those of 1,972 matched classmates who were known to be alive and cancer-free at the time subjects with cancer had died or were diagnosed. Students with a record of proteinuria at college physical examination experienced increased risk of kidney cancer. Higher levels of body weight during college were associated with elevated risks of kidney and bladder cancers; however, increased weight in 1962/1966 related only to kidney cancer. A history of cigarette smoking as reported by questionnaire in 1962/1966 predicted increased occurrence of bladder cancer. Students with a history of tonsillectomy at college entrance experienced increased risk of prostate cancer, and those who reported cancer history in 1 or both parents were at increased risk for testicular cancer. These and other findings are presented as clues deserving further exploration for any etiological significance they may hold for the cancer sites studied.