Louis J. Marchitelli

Training responses of plasma beta-endorphin, adrenocorticotropin, and cortisol.

The purpose of this study was to examine the effects of three different run training programs on plasma responses of beta-endorphin (beta-EP), adrenocorticotropin (ACTH), and cortisol to maximal treadmill exercise. Subjects were randomly assigned to one of three training groups: sprint intervals (SI) (N = 8), endurance (E) (N = 10), or combination (C) (N = 7). Training was monitored for 10 wk, and maximal treadmill exercise tests were administered pre-training and after 2, 4, 6, 8, and 10 wk of training. Blood samples were obtained (pre-training and after 10 wk) before, immediately after, and 5 and 15 min following the maximal exercise tests. All groups significantly (P less than 0.05) increased maximal oxygen consumption values at 8 and 10 wk of the training period. Significant exercise-induced increase in plasma beta-EP, ACTH, cortisol, and blood lactate were observed for both pre- and post-training tests in all training groups. The SI group demonstrated significant post-training increases in beta-EP, ACTH, cortisol, and 5 min post-exercise blood lactate concentrations in response to maximal exercise. No training-induced hormonal changes were observed for the E group. While exercise-induced increases were observed, the C group exhibited significant post-training reductions in plasma responses of beta-EP, ACTH, and blood lactate concentrations in response to maximal exercise. Still, resting and post-exercise increases in plasma cortisol concentrations were significantly higher in magnitude in the post-training test. Lactate was significantly correlated with beta-EP (r = 0.72), ACTH (r = 0.70), and cortisol (r = 0.64).(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma Opioid Peptide Responses During Heat Acclimation in Humans

Plasma beta-endorphin, Met-enkephalin and Peptide F immunoreactivity (ir) were measured at rest and following exercise on three days (days 1, 4, 8) of an eight day heat acclimation regime. Fourteen male subjects demonstrated physiological heat acclimation adaptations. Our data demonstrated a differential response of peripheral plasma levels of endogenous opioid peptides (EOP) to exercise in the heat. In addition, EOP did not follow the same time-course of other physiological adaptations as no differences (day 1 vs. 4 vs. 8) in resting or exercise levels were observed over the eight day heat acclimation regime. Significant increases in beta-endorphin ir (pre- to post-exercise) appear to reflect concomitant exercise-heat related changes. The increased peripheral levels of beta-endorphin were correlated to plasma levels of cortisol. Heat and exercise stress may result in a reduction of Met-enkephalin ir observed in peripheral plasma and might be due to degradation or a decrease in processing from the larger precursors. The differential responses of EOP suggest the possibility of separate physiological roles for these peptides during exercise in the heat but peripheral plasma levels of EOP do not appear to reflect acute heat acclimation changes.

The effects of graded exercise on plasma proenkephalin peptide F and catecholamine responses at sea level

SummaryThe purpose of this study was to evaluate the effects of graded treadmill exercise on plasma preproenkephalin peptide F immunoreactivity and concomitant catecholamine responses at sea level (elevation, 50 m). Few data exist regarding the sea-level responses of plasma peptide F immunoreactivity to exercise. Thirty-five healthy men performed a graded exercise test on a motor-driven treadmill at the relative exercise intensities of 25, 50, 75, and 100% of maximum oxygen consumption (VO2max). Significant (P<0.05) increases above rest were observed for plasma peptide F immunoreactivity and norepinephrine at 75 and 100% of the VO2max and at 5 min into recovery. Significant increases in plasma epinephrine were observed at 75 and 100% of VO2max. Whole blood lactate significantly increased above resting values at 50, 75, and 100% of the VO2max and at 5 min into recovery. These data demonstrate that exercise stress increases plasma peptide F immunoreactivity levels at sea level. While the exercise response patterns of peptide F immunoreactivity are similar to catecholamines and blood lactate responses, no bivariate relationships were observed. These data show that sea-level response patterns to graded exercise are similar to those previously observed at moderate altitude (elevation, 2200 m).

Influence of altitude and caffeine during rest and exercise on plasma levels of proenkephalin Peptide F

The purpose of this study was to examine the resting and exercise response patterns of plasma Peptide F immunoreactivity (ir) to altitude exposure (4300 m) and caffeine ingestion (4 mg.kg b.w.-1). Nine healthy male subjects performed exercise tests to exhaustion (80-85% VO2max) at sea level (50 m), during an acute altitude exposure (1 hr, hypobaric chamber, 4300 m) and after a chronic (17-day sojourn, 4300 m) altitude exposure. Using a randomized, double-blind/placebo experimental design, a placebo or caffeine drink was ingested 1 hour prior to exercise. Exercise (without caffeine) significantly (p less than 0.05) increased plasma Peptide F ir values during exercise at chronic altitude only. Caffeine ingestion significantly increased plasma Peptide F ir concentrations during exercise and in the postexercise period at sea level. Conversely caffeine ingestion at altitude resulted in significant reductions in the postexercise plasma Peptide F ir values. The results of this study demonstrate that the exercise and recovery response patterns of plasma Peptide F ir may be significantly altered by altitude exposure and caffeine ingestion. These data support further study examining relationships between Peptide F (and other enkephalin-containing polypeptides) and epinephrine release in response to these types of physiological stresses.

Responses of plasma human atrial natriuretic factor to high intensity submaximal exercise in the heat

SummaryNo data exists regarding responses of human atrial natriuretic factor (ANF) to exercise in the heat. The purpose of this study was to examine the responses of plasma ANF to high intensity submaximal (71%±0.9

Hormonal and growth factor responses to heavy resistance exercise protocols

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Changes in hormonal concentrations after different heavy-resistance exercise protocols in women

) exercise in the heat over an eight day acclimation period. Fourteen healthy males volunteered to participate in the study. Subjects performed intermittent exercises on a treadmill (0% grade) during 50 min of each 100 min trial in an environmental chamber maintained at 41.2±0.5° C, 39.0±1.7% relative humidity. Blood was obtained from an antecubital vein after standing 20 min in the heat prior to exercise, and immediately after exercise. Measures were compared on days 1, 4 and 8. ANF did not change pre- to post-exercise nor did it change over the eight day heat acclimation period despite other heat acclimation adaptations. Conversely, plasma aldosterone (ALDO), renin activity (PRA) and cortisol (COR) all increased (p<0.05) pre- to post-exercise on each day but again no changes were observed over the eight day period. These data support that ANF may not increase when ALDO and PRA increases are observed.

Effects of different heavy-resistance exercise protocols on plasma beta-endorphin concentrations

To determine if exercise training alters the pattern and magnitude of plasma concentrations of proenkephalin Peptide F and epinephrine, plasma proenkephalin [107-140] Peptide F(ir) and catecholamines were examined pre-training (T-1), and after 4- (T-2), 8- (T-3), and 12-weeks (T-4) of training. 26 healthy men were matched and randomly assigned to one of three groups: heavy resistance strength training (Strength, n=9), high intensity endurance training (Endurance, n=8), or both training modalities combined (Combined, n=9). Blood was collected using a syringe with a cannula inserted into a superficial arm vein with samples collected at rest, after each 7 min stage and 5 and 15 min into recovery. With training, all groups observed shifted plasma Peptide F responses to graded exercise, where significant increases were observed at lower exercise intensities. Increases in plasma epinephrine with exercise were observed in all groups. The Combined group saw increases at 25% at T-3 and for 50% at T-2, T-3, and T-4 which was higher than T-1. The Endurance group demonstrated increases for 50% at T-1, T-2, T-3 but not at T-4. The plasma epinephrine response to graded exercise was reduced in the Strength group. Increases in plasma norepinephrine above rest were observed starting at 50% . The Strength group demonstrated a significant reduction in norepinephrine observed at 100% at T-3 and T-4. Peptide F and catecholamines responses to graded exercise can be altered by different types of physical exercise training. Simultaneous high intensity training may produce adrenal medulla exhaustion when compared to single mode training.