E. F. De Palo

Plasma lactate, GH and GH-binding protein levels in exercise following BCAA supplementation in athletes

Summary. Branched chain amino acids (BCAA) stimulate protein synthesis, and growth hormone (GH) is a mediator in this process. A pre-exercise BCAA ingestion increases muscle BCAA uptake and use. Therefore after one month of chronic BCAA treatment (0.2 g kg−1 of body weight), the effects of a pre-exercise oral supplementation of BCAA (9.64 g) on the plasma lactate (La) were examined in triathletes, before and after 60 min of physical exercise (75% of VO2max). The plasma levels of GH (pGH) and of growth hormone binding protein (pGHBP) were also studied. The end-exercise La of each athlete was higher than basal. Furthermore, after the chronic BCAA treatment, these end-exercise levels were lower than before this treatment (8.6 ± 0.8 mmol L−1 after vs 12.8 ± 1.0 mmol L−1 before treatment; p < 0.05 [mean ± std. err.]). The end-exercise pGH of each athlete was higher than basal (p < 0.05). Furthermore, after the chronic treatment, this end-exercise pGH was higher (but not significantly, p = 0.08) than before this treatment (12.2 ± 2.0 ng mL−1 before vs 33.8 ± 13.6 ng mL−1 after treatment). The end-exercise pGHBP was higher than basal (p < 0.05); and after the BCAA chronic treatment, this end-exercise pGHBP was 738 ± 85 pmol L−1 before vs 1691 ± 555 pmol L−1 after. pGH/pGHBP ratio was unchanged in each athlete and between the groups, but a tendency to increase was observed at end-exercise.The lower La at the end of an intense muscular exercise may reflect an improvement of BCAA use, due to the BCAA chronic treatment. The chronic BCAA effects on pGH and pGHBP might suggest an improvement of muscle activity through protein synthesis.

IGF-I/IGFBP system: metabolism outline and physical exercise.

The GH/IGF-I system plays a well-known hormonal role and its effects, mainly anabolic and insulin-sensitizing, are mediated through endocrine as well as paracrine/autocrine mechanisms. This system includes the binding proteins, namely GH binding proteins and IGF-I binding proteins (IGFBP). As expected, this axis plays a key role in organism modification in consequence of a physical exercise. Physical activity, training, and exercise capacity chiefly involve anabolism process modifications of various tissues, in particular muscular adjustments. Numerous investigators found a correlation among the level of exercise tolerance, muscle strength or walking speed and IGF-I/IGFBP-3 concentrations. However, also inverse and absent correlations between circulating IGF-I concentrations and acute or chronic exercise responses have been reported. IGF-I is generally accepted as an important GH mediator with metabolic effects, through both endocrine and paracrine or autocrine mechanisms. GH is the main regulator of the hepatic synthesis of IGF-I and IGFBP-3, which is the most abundant IGF carrier in human plasma. Recently, it has been shown that the physical exercise stimulatory impact on skeletal muscles is mediated through an increased local IGF-I synthesis with an IGFPB involvement. An absent association of exercise performance and circulating IGF-I may indicate that exercise will exert muscle strength by predominately locally derived paracrine or autocrine mediators rather than endocrine circulating IGF-I. The present review considers the general aspects of the IGF/IGFPB system and the role of the IGF/IGFPB system in relation to physical exercise (type, duration, etc.) taking into account the training aspects.

Gender-, age-, body composition- and training workload-dependent differences of GH response to a discipline-specific training session in elite athletes: a study on the field.

Ninety-nine Italian elite athletes (61 M, 38 F, mean age±SE: 24.1±0.6 yr, age range: 17–47 yr) of different disciplines volunteered to participate in this investigation. Basal GH concentrations were significantly higher (p<0.0001) in females (6.2±1.1 ng/ml) vs males (1.9±0.5 ng/ml). Basal GH values were negatively correlated with age and body mass index (BMI); no significant correlation was found between GH and IGF-I levels. Among female athletes, 8/38 had basal GH values higher than 10 ng/ml [2/8 athletes were taking oral contraceptives (OC)], while among males 6/61 had values higher than 5 ng/ml. In females, training sessions significantly increased (p<0.0001) basal GH concentrations (peak GH: 18.5±1.9 ng/ml), while in males GH responses were lower than in females (11.8±1.4 ng/ml, vs F: p<0.005). Six out of 38 female and 6/61 male athletes were considered GH hypo-responders (i.e. negative difference between peak GH and basal GH values), the large majority of them being subjects with elevated basal GH concentrations. In responsive athletes, peak GH values occurred immediately at the end of the training session both in males and in females; GH concentrations rapidly declined during recovery. No significant correlations were found between peak GH and age, body weight and BMI in either gender. GH responses were directly related (p<0.001) to the intensity of the workload during the sessions. In conclusion, the present study demonstrates that: 1) some elite athletes had increased GH concentrations before training, which were however associated with normal IGF-I levels; 2) GH peaks after a discipline-specific training session were significantly higher in females than in males performing the same discipline, gender-related differences disappearing when post-exercise total GH outputs (area under the curve) were compared; 3) peak GH values were directly correlated with training workload; 4) GH concentrations rapidly declined during recovery, values at the end of the post-training GH sampling being generally lower than those found in basal condition.

Free carnitine and acetyl carnitine plasma levels and their relationship with body muscular mass in athletes

SummaryThe purpose of the present study was to investigate the relationship between plasma carnitine concentration and body composition variation in relation to muscular and fat masses since there is no experimentally proved correlation between plasma carnitine and body masses. We used bioelectric impedance analysis (BIA), to determine body composition and to have a complete physical fitness evaluation. The post-absorptive plasma free carnitine and acetyl carnitine plasma levels, body composition as Fat-Free Mass (FFM) and Fat Mass (FM) in kg, as well as in percent of body mass, were analysed in 33 healthy subjects. A significant negative correlation was found between plasma acetyl carnitine and FFM in weight (kg) as well as in percent of body mass (respectively p < 0.0001; p < 0.01); a significant positive correlation was found only between FM in percent and plasma acetyl carnitine (p < 0.01). The observed negative correlation between plasma acetyl carnitine and muscular mass variation might reflect an oxidative metabolic muscle improvement in relation to muscular fat free mass increment and might be evidence that muscle metabolism change is in relation to plasma acetyl carnitine concentration.

Elite volunteer athletes of different sport disciplines may have elevated baseline GH levels divorced from unaltered levels of both IGF-I and GH-dependent bone and collagen markers: a study on-the-field.

Seventy-seven Italian elite athletes (42 M, 35 F, mean age±SE: 24.4±0.7 yr, age range: 17–47 yr) of different sport disciplines (sprinters, triathletes, middle-distance runners, road-walkers, cyclists, rowing athletes, skiers, roller hockey players, swimmers) were sampled on-the-field (before a training session) for the determination of basal GH, IGF-I, C-terminal cross-linked telopeptide of type I collagen (ICTP) and amino-terminal propeptide of type III procollagen (PIIINP) levels, two GH-dependent peripheral markers of bone and collagen turnover, respectively. Basal GH concentrations were significantly higher (p<0.001) in female (5.8±1.0 ng/ml) vs male athletes (1.8±0.5 ng/ml), with a large spread of values in either gender. Mean GH levels of athletes were significantly higher than those recorded in agematched sedentary controls (females: 2.5±0.5 ng/ml, p<0.001; males: 0.5±0.2 ng/ml, p<0.05). Among female athletes, 7/35 had basal GH values higher than the upper limit of control values (>9.5 ng/ml), while among males 7/42 had values higher than the upper limit of male sedentary controls (>3.6 ng/ml). No significant differences in basal GH concentrations were found between females taking oral contraceptives (OC) and those who did not receive this treatment (5.0±2.1 vs 6.0±1.2 ng/ml). IGF-I levels (236.4±7.8 ng/ml) were in the normal range for age in all athletes (except for 1 athlete with slightly increased levels), no significant correlation being found between GH and IGF-I levels (R2=0.0393). Mean ICTP (4.6±0.2 ng/ml) and PIIINP (4.4±0.1 ng/ml) concentrations of elite athletes were not significantly different from those recorded in age and matched healthy sedentary subjects; 4 athletes showed increased PIIINP levels and 2 had increased ICTP levels. ICTP and PIIINP levels were positively correlated with chronological age (p<0.001), a positive correlation being also found between the two markers (p<0.001). On the contrary, no significant correlation was found between basal GH/IGF-I levels and ICTP/PIIINP levels. In conclusion, the present study demonstrates that: 1) elite athletes (particularly females), which have frequently increased basal GH on-the-field, have actually normal IGF-I levels; 2) ICTP and PIIINP levels of athletes are similar to those recorded in healthy sedentary, being significantly higher in younger subjects of both groups; 3) the presence of increased basal GH levels, being associated with normal IGF-I, ICTP and PIIINP levels, is probably the result of a transient GH peak in this study group. Further additional studies are requested to verify the possible use of these peripheral GH-dependent markers for detecting exogenous chronic administration of recombinant GH in athletes.

Circulating immunoreactive proANP(1–30) and proANP(31–67) responses to acute exercise

The circulating immunoreactive atrial natriuretic peptide (C-terminal; alpha-ANP) increases during exercise to become suppressed in the first hours of the recovery. The response of the N-terminal ANP fragments to acute exercise is not known while proANP (31-67) appears to be elevated with chronic exercise. We evaluated the plasma concentrations of the N-terminal ANP fragments (1-30) and (31-67) in oarsmen (n=10) before and after two acute exercise bouts separated by 5 h. As control, measurements were made on a day with no exercise (n=12). At rest, the concentrations of proANP(1-30) and proANP(31-67) were 344+/-42 and 810+/-172 pmol x l(-1), respectively. Half an hour after the first exercise bout, proANP(1-30) was elevated (to 404+/-48 pmol x l(-1); P<0.05) and decreased below the pre-exercise level (to 316+/-41 pmol x l(-1); P<0.05) 4 h into the recovery period. Also, 30 min after the second exercise session, the concentration of proANP(1-30) was elevated to 408+/-45 pmol x l(-1) (P<0.05) and the pre-exercise level was re-established on the following morning. Thus, proANP(1-30), rather than proANP(31-67), responded to acute exercise. These results suggest that atrial distension and, therefore, the central blood volume changes markedly in athletes during a day with repeated exercise bouts.

Branched chain amino acids chronic treatment and muscular exercise performance in athletes: a study through plasma acetyl-carnitine levels

SummaryIn relation to energy request during physical exercise, muscular tissue Branched Chain Amino Acids (BCAA) are metabolized particularly when the oxidation rises. But in the whole-human body, it is difficult to estimate, in a quantitative sense, the role played by BCAA in sustaining exercise. During a BCAA treatment, made on a group of athletes kept under observation, it was observed, through Conconis test, that this treatment influenced physical performance. Aim of present work is to investigate if BCAA chronic treatment effect on physiological trial is confirmed on blood circulating biochemical energy parameters and in particular on acetyl-carnitine, since acetyl-linked compounds may be an important biochemical factor.Fourteen athletic well trained male subjects, were randomly divided into two subgroups; a first group was submitted to a chronic treatment (n = 7) of BCAA (oral intake was 0.2 g/Kg die) and a second group, as controls (n = 7), assumed oral placebo. Conconis test demonstrated a significant difference (p < 0.005) in the exercise performance of the two sub-groups, comparing the measurements of ratios of deflection velocity (Vd), before and after the treatment. Therefore we studied the athletes performing a muscular exercise test (40 Km/h, cycle race, for 90 min) after one month of treatment. During this treatment period the subjects followed a well standardized diet. Samples of blood were drawn before, at the end and during the recovery (60 min) to study if traditional biochemical parameters varied and confirmed the observed differences in Conconis test. The measurements of concentrations of FFA, KB, free carnitine, acetyl-carnitine and BCAA were performed. Plasma BCAA levels did not demonstrate variations either before or after the exercise performance, or between the two groups. The biochemical factors, substrates and hormones, KB, FFA, lactate, insulin and growth hormone plasma levels did not demonstrate significant differences from the patterns present in literature. Plasma free and acetyl-carnitine followed the well known variations, but only acetyl-carnitine levels demonstrated, at the end increase in acetyl-carnitine levels could be related to a minor fatigue situation and to a larger energy supply availability perhaps present in BCAA treated athletes (Sahlin et al., 1990; May et al., 1989). Both mentioned hypothesis seem in concordance with a smaller acetyl-CoA substrate accumulation, or better for present study, is even more successful with athletes who give a better physical performance. In fact Conconis test in the two sub-groups of athletes seems to suggest that BCAA treated athletes were able to give a better performance, furthermore out of curiosity we point out that the athletes treated with BCAA won more races than the untreated.We would also like to add in conclusion that although confirming the difficulties of studies in the whole-body, our work gives an interesting clue about the possibility to use acetyl-carnitine plasma levels to understand the biochemical importance of the BCAA as substrate able to influence physical performance, but further research is needed.The phenomenon presence might be showed better perhaps by studying untrained groups during prolonged exercise and with physical performance at exhaustion. If treatment were able to help the physical performance and to shift the fatigue, then confirmation might be a less raised plasma acetyl-carnitine level. In effect blood ammonium levels in present study did not demonstrate any variation in and between sub-groups; this latter observation could be caused by the quantity of work load, and training state of the athletes (Ji et al., 1987; Kirkendall, 1990). Moreover, as observed by Hageloch et al. (1990), the ammonia increases less during prolonged endurance exercise, and in fact the athletes of present study were all middle distance racing cyclists, and the physical performance was a prolonged endurance exercise.

Salivary free Insulin-like Growth Factor-I levels: Effects of an acute physical exercise in athletes

Background/aims: The offer of human saliva IGF-I (sIGF-I) measurement in athletes investigation is a new proposal. The aim was to investigate the physical exercise effect on sIGF-I and explore plasma free IGF-I relation. Materials and methods: Saliva and blood were collected from well-trained athletes, investigated immediately before and at the end of a physical exercise test. Results: sIGF-I was significantly increased at the end of the physical exercise. The plasma free IGF-I concentrations did not demonstrate any difference. The saliva total protein level (sTP) was also significantly increased. A positive correlation between sTP and sIGF-I, was observed, both before and after physical exercise, and between salivary and plasma free IGF-I only after physical exercise. The salivary free IGF-I level significantly increased after physical exercise, moreover a correlation with the plasma levels exists in post-exercise condition. Conclusion: The physical exercise affects sIGF-I as well as the sTP. The correlation between plasma and salivary free IGF-I levels only in post-exercise condition suggests further studies to investigate the effects of different type and duration of physical exercise. The comparison with other salivary biochemical parameter investigation would also further increase comprehension on the role of salivary IGF-I.

Branched-chainα-amino acid chronic treatment: responses of plasmaα-keto-related compounds and ammonia when used in physical exercise performance.

SummaryTo examine the effects of acute branched-chainα-amino acids (BCAA) oral administration following chronic BCAA intake, a group of well trained young swimmers (n = 12) was submitted to a one month chronic BCAA treatment (0.2g/Kg body weight per die; Leu: Val: Ileu = 2:1:1) and a physical exercise test before and after this period of treatment was carried out. The exercise tests (60min swim) were performed in a high circulating BCAA level state which was obtained through oral BCAA administration (or placebo) just before the beginning of the exercise. The groups will be referred to as BCAA/before, BCAA/after, placebo/before, placebo/after. Blood and plasma (antecubital vein) samples were collected from the different groups at different times: on the morning of the day before the test (basal time, rest 0), the following day 30min after an acute administration (oral dose placebo or BCAA acute treatment: Leu 4.8g, Val 2.4g, Ileu 2.4g), just before the beginning of the exercise performance (time 0min, rest 1), at the end of the exercise (time 60min, EE) and during recovery (time 120min, Re). Plasma ammonia levels increased significantly from rest 1 to the end of the exercise in all subjects, but it was significantly higher in BCAA treated than in placebo subjects in both the before and after chronic treatment groups (BCAA/before: from 38 ± 7 to 204 ± 65mmol/l; placebo/before: from 36 ± 10 to 93 ± 29mmol/l; BCAA/after: from 36 ± 9 to 171 ± 43mmol/l; placebo/after: from 30 ± 6 to 65 ± 16mmol/l). Plasma ammonia level increments observed before a chronic one month BCAA treatment were significantly higher than after this treatment (p < 0.05). Plasma alanine was at all times of the test higher before the BCAA chronic treatment than after; this difference resulted significant at rest 0, rest 1 and recovery times (p < 0.05). After acute BCAA administration, plasma BCAA levels increased from 618 ± 52mmol/l to 1893 ± 284mmol/l (p < 0.05) from the onset of exercise and remained elevated throughout the test. Placebo and basal (rest 0) levels both before and after the chronic treatment did not demonstrate any significant differences. Plasma BCAA and BCKA levels, in the BCAA/before demonstrated significantly higher levels than placebo/before at rest 1 time (BCAA/before vs placebo/before: Leu 86 ± 27 vs 620 ± 97mmol/l; KIC 60 ± 3 vs 87 ± 5mmol/l, Ileu 51 ± 19 vs 359 ± 56mmol/l, KMV 26 ± 1 vs 43 ± 2mmol/l, Val 290 ± 79 vs 915 ± 133mmol/l, KIV 14 ± 1 vs 24 ± 2mmol/l). The levels after the chronic treatment maintained circa these differences in the two groups BCAA/after and placebo/after. The plasma BCAA as well as the BCKA levels of acutely treated athletes, in physical exercise, showed a different profile before and after the chronic treatment. The chronic treated BCAA/after group in fact depicted a decreasing BCKA level profile at the end of the exercise and during recovery; on the contrary, before the chronic treatments, acutely treated athletes demonstrated a tendency to increase these levels during recovery. These data seem to confirm that increased BCAA availability, before exercise, result in significantly greater plasma ammonia responses during exercise than does placebo administration; furthermore this increment is lower after chronic treatment. The interpretation of the ammonia data is difficult since the exercise type could have an influence on this phenomenon. The differences in the profile patterns of alanine, BCAA and BCKA levels seem to indicate that the chronic treatment brings about a state in which there is a better use of BCAA compounds as energy supply.

Plasma Acetyl-Carnitine Concentrations during and after a Muscular Exercise Test in Patients with Liver Disease

In many human tissues, fuel is stored for immediate use, as well as for energy exchange between different parts of the body. Fat and glycogen represent, together with proteins, the principal energy storage materials. During energy requirement, e.g. muscular exercise, glycogen as a local reserve, is used first to supply energy needs. Acetyl-carnitine, as an active molecular group, represents an intermediate substrate, usable directly in the working tissue. The present study investigates whether plasma acetyl-carnitine could be a useful biochemical measure for information on fuel exchange in the body, and whether it is a rapidly available energy source exchangeable among tissues with different metabolic functions, such as muscle and liver. The present study investigated control and hepatopathic subjects after maximal and submaximal muscular exercise. Hepatopathic patients may be a useful model, as liver carnitine metabolism is likely to be impaired. Plasma acetyl-carnitine before, during and after maximal exercise in hepatopathic subjects did not differ, while in normal subjects it increased. After submaximal exercise, acetyl-carnitine increased in patients, as well in controls. In the patients (n = 9) with liver metabolism disorders we observed that during maximal exercise plasma acetyl-carnitine varied from 3.26 +/- 2.18 mumol/l (time 0 min) to 4.30 +/- 2.02 mumol/l (time 20 min) and from 1.99 +/- 1.36 mumol/l to 4.83 +/- 2.60 mumol/l (p less than 0.05) in the controls (n = 7).(ABSTRACT TRUNCATED AT 250 WORDS)