Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In four independent studies, sex differences in cortisol responses to psychological stress were investigated in healthy adolescents and adults (total n = 153). Public speaking and mental arithmetic in front of an audience (Studies 1-3) reliably induced increases in free cortisol levels in both sexes with 2- to 4-fold increases above baseline levels. Mean cortisol responses were 1.5- to 2-fold higher in men compared with women. In Study 3, cortisol profiles were additionally investigated after human corticotropin-releasing hormone (h-CRH) and bicycle ergometry until exhaustion. Here, both sexes showed very similar adrenocortical responses. Furthermore, men showed elevated cortisol levels in anticipation of the psychological stress situation without actually having to perform the tasks (Study 4). Under this condition cortisol concentration was unchanged or decreased in women. From these data we conclude that the observed sex difference does not reflect an overall lower responsiveness of the female adrenal cortex. Although these studies do not provide conclusive data, we suggest sex differences in cognitive and/or emotional responses to distressing psychosocial situations which in turn may influence cortisol secretion.
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PMID:Consistent sex differences in cortisol responses to psychological stress. 145 58

The effects of low blood glucose concentration during low-intensity prolonged physical exercise on the hypothalamus-pituitary-adrenocortical axis were investigated in healthy young men. In experiment 1, six subjects who had fasted for 14 h performed bicycle exercise at 50% of their maximal O2 uptake until exhaustion. At the end of the exercise, adrenocorticotropic hormone (ACTH) and cortisol increased significantly. However, this hormonal response was totally abolished when the same subjects exercised at the same intensity while blood glucose concentrations were maintained at the preexercise level. In experiment 2, in addition to ACTH and cortisol, the possible changes in plasma concentration of corticotropin-releasing factor (CRF) were investigated during exercise of the same intensity performed by six subjects. As suggested by a previous study (Tabata et al. Clin. Physiol. Oxf. 4: 299-307, 1984), when the blood glucose concentrations decreased to less than 3.3 mM, plasma concentrations of CRF, ACTH, and cortisol showed a significant increase. At exhaustion, further increases were observed in plasma CRF, ACTH, and cortisol concentrations. These results demonstrate that decreases in blood glucose concentration trigger the pituitary-adrenocortical axis to enhance secretion of ACTH and cortisol during low-intensity prolonged exercise in humans. The data also might suggest that this activation is due to increased concentration of CRF, which was shown to increase when blood glucose concentration decreased to a critical level of 3.3 mM.
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PMID:Effect of low blood glucose on plasma CRF, ACTH, and cortisol during prolonged physical exercise. 166 96

The peptidergic, endogenous opioid system counteracts exogenous and endogenous stress factors. The system will be activated by stress, e.g., also in case of heart failure. The endogenous opioids endorphin, met-enkephalin, leu-enkephalin, dynorphin, casomorphin, and others split from precursor proteins (250-265 amino acids) by a specific proteolytic cleavage. In clinical and experimental heart failure the plasma levels of endorphin and lipotropin are changed as an evidence of the activated opioid system. In patients with chronic heart failure the plasma levels of endorphin and lipotropin are decreased, which is discussed as an exhaustion of the opioid system. In the case of experimentally induced right-heart failure in dogs the plasma levels of endorphin and lipotropin are increased. Morphine antagonists (naloxone hydrochloride) which penetrate into the cerebral system improve the disturbed hemodynamics in dogs with a right-heart failure. The improving effects results from central actions since opiate antagonists, which cannot penetrate the blood-brain-barrier (naloxone methobromide) have no effect. The actions of opioid peptides will be induced by inhibition of the depletion and the reabsorption of catecholamines in synaptic storages (isolated atria from guinea pig). In cultures from cardiac myocytes (chicken ventricle cells) enkephalins induced positive inotropic effects via receptor mediated mechanisms. The results showed modulating activities of endogenous opioids against the effect of activated sympathetic activity.
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PMID:[Role of endogenous opioids in heart failure]. 166 29

Neuroendocrine and sympathoadrenal responses to exhaustive graded treadmill exercise were examined in 17 male subjects of varying degrees of fitness. The mean duration of exercise to exhaustion was 15.2 +/- 0.7 (+/- SE) min. Exercise duration was inversely correlated with baseline heart rate (P less than 0.05). Compared to standing baseline values, mean plasma norepinephrine and epinephrine levels increased 339% and 301%, respectively, in an integrated 2-min blood sample collected immediately after completion of exercise. Mean adrenocorticotrophic hormone (ACTH), beta-endorphin (beta-EP), beta-lipotropin (beta-LPH), and prolactin levels increased 282%, 720%, 372%, and 211%, respectively, in an integrated 4-min blood sample beginning 2 min after completion of exercise. Cortisol levels increased 183% in the sample collected 17-21 min after exercise. The magnitude of these neuroendocrine responses to exercise was similar among individuals at the same relative intensity of exhaustive exercise, regardless of the duration of exercise. The exercise-induced increases of the pro-opiomelanocortin (POMC)-derived peptides, ACTH, beta-EP, and beta-LPH, were highly correlated with each other (P values less than 0.001), and were correlated with prolactin increases, (P values less than 0.05). During a 20-min recovery period after exercise, changes in heart rate, ACTH, and beta-LPH levels were correlated with duration of exercise, (P less than 0.01, P less than 0.03, and P less than 0.03, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The influence of fitness on neuroendocrine responses to exhaustive treadmill exercise. 215 74

The purpose of this study was to investigate the effects of physical training on the responses of serum adrenocorticotropic hormone (ACTH) and cortisol concentration during low-intensity prolonged exercise. Five subjects who had fasted for 12 h cycled at the same absolute intensity that elicited 50% of pre-training maximal oxygen uptake (VO2max), either until exhaustion or for up to 3 h, before and after 7 weeks of vigorous physical training [mean daily energy consumption during training exercise, 531 kcal (2230 kJ)]. In the pretraining test, serum ACTH and cortisol concentrations did not increase during the early part of the exercise. Increases in concentrations of both hormones occurred in all subjects when blood glucose concentration decreased during the later phase of the exercise. The mean values and SEM of serum ACTH and cortisol concentrations at the end of the exercise were 356 ng.l-1, SEM 79 and 438 micrograms.l-1, SEM 36, respectively. After the physical training, VO2max of the subjects improved significantly from the mean value of 50.2 ml.kg-1.min-1, SEM 2.5 to 57.3 ml.kg-1.min-1, SEM 2.0 (P less than 0.05). In the post-training test, exercise time to exhaustion was prolonged in three subjects. Comparing the pre- and post training values observed after the same length of time that the subjects had exercised in the pre-training test, the post-training values of serum ACTH (44 ng.l-1, SEM 3) and cortisol (167 micrograms.l-1, SEM 30) concentration were less than the pre-training value (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of physical training on the responses of serum adrenocorticotropic hormone during prolonged exhausting exercise. 217 89

Twelve trained male athletes were subjected to a progressive intensity treadmill exercise test to total exhaustion and at a later date took part in the Comrades Marathon. Blood was taken in order to determine whether plasma met-enkephalin levels increase in an exercise-intensity dependent manner. The mean concentrations in f mol/ml were as follows: post-exercise levels (266) were significantly higher than basal levels (172), and the post-marathon levels (378) rose significantly above the post-exercise levels. The magnitude of the responses is thus correlated with the amount of work performed and would suggest that this opioid peptide is involved in physiological actions that perhaps extend beyond the pharmacological actions of opiate drugs.
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PMID:Circulating met-enkephalin in trained athletes during rest, exhaustive treadmill exercise and marathon running. 234 64

beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) concentrations were measured in the basal state and after acute exercise for 15 min or until exhaustion in 6 physically conditioned male volunteers. Serum concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone and prolactin were also measured in the basal state. In addition, the concentrations of the gonadotropins (LH and FSH) were determined after exercise and the gonadotropin response to gonadotropin releasing hormone was assessed before and after exercise. The data show that acute exercise stimulates the release of both beta-EP and beta-LPH which return to base-line levels within 60 min after exercise. This is in contrast to our previously described results in physically unconditioned male volunteers in whom only beta-LPH release was noted after exercise. Serum LH concentrations declined after exercise reaching nadir values between 60 to 150 min after exercise. As we previously reported in physically unconditioned male volunteers, serum FSH concentrations did not change with exercise and the gonadotropin response to LRH stimulation was uninfluenced by exercise. Serum testosterone and prolactin concentration were within the normal range for healthy adult males. We speculate that the difference in beta-EP release with exercise in physically conditioned and unconditioned males represents a difference in processing of the opioid precursor molecule (pro-opiomelanocortin, POMC) in the two groups.
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PMID:Beta-endorphin/beta-lipotropin release and gonadotropin secretion after acute exercise in physically conditioned males. 252 54

It is well established that prolactin release during exercise is one of the important factors in exercise-induced menstrual dysfunction. The purpose of this study is to clarify the mechanisms of prolactin release during exercise. Ten female athletes measured their BBT every morning. They performed incremental exercise on a cycle ergometer, with or without naloxone, on the 5th to 8th days of the follicular phase. Three minutes before the exercise, 0.4mg of naloxone was injected intravenously and a further 1.6mg/hr of naloxone was continuously infused during exercise. Blood samples were collected after 60 minutes bed rest (Rest), at the time when the heart rates reached 150 bpm (Submax), the point of exhaustion (Max) during exercise and after 60 minutes bed rest following exercise (After 1hr). The levels of prolactin in serum, dopamine, beta-endorphin. VIP and ACTH in the plasma were measured. Whereas prolactin increased significantly at Submax (p less than 0.05) and Max (p less than 0.001), the increase in prolactin was suppressed by the administration of naloxone (p less than 0.05). Dopamine showed no remarkable change during exercise, with or without naloxone. There were significant increases in beta-endorphin at Max (p less than 0.001), VIP at Submax and Max (p less than 0.001), but these increases were suppressed by the administration of naloxone (p less than 0.001). ACTH which had markedly increased at Submax (p less than 0.025) and Max (p less than 0.001) showed a slight tendency to decrease following the administration of naloxone, but there were no significant differences in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of naloxone on hormonal changes during exercise. 255 87

Twenty-four unfit volunteers and twenty-three superfit athletes were subjected to a progressive intensity treadmill exercise to total exhaustion in order to study the plasma met-enkephalin response to exercise. Blood samples were collected before and 5 min post-exercise. The basal met-enkephalin levels were significantly higher in the superfit individuals (180 fmol.ml-1) than in the unfit individuals (126 fmol.ml-1). Post-exercise the increase from basal levels of plasma met-enkephalin was significantly higher in the superfit athletes (180-278 fmol.ml-1) than in the unfit individuals (126-157 fmol.ml-1). The magnitude of the met-enkephalin responses to exercise therefore appears to be dependent on the amount of work performed and the degree of previous physical training. Peripherally circulating opioid peptides may, therefore, possibly play a role in the body's adaptation to exercise training.
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PMID:Effect of exercise on met-enkephalin in unfit and superfit individuals. 259 73

The concentrations of endogenous opiates (beta-endorphin, methionine-enkephalin, leucine-enkephalin) in the spinal fluid and arterial blood plasma has been studied in 16 dogs, using the model of acute pain stimulation under electroacupuncture analgesia (EAA). It has been shown that pain stimulation under EAA is accompanied by a significant increase in methionine-enkephalin++ and leucine-enkephalin concentrations (by 244 and 69.4%, respectively) in the spinal fluid. beta-endorphin level tends to increase. There is also a trend towards the reduction in beta-endorphin and methionine-enkephalin concentrations in the arterial blood plasma, which is indicative of effective antinociceptive stimulation of the endogenous opiate system. However, by the end of the first hour a decrease of methionine-enkephalin and leucine-enkephalin levels in the spinal fluid was paralleled by a trend towards beta-endorphin and methionine-enkephalin increase and a significant leucine-enkephalin increase in arterial blood plasma, which can account for the exhaustion of the opiate system.
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PMID:[Changes in the concentration of endogenous opiates in the blood and cerebrospinal fluid during acute painful stimuli and protective electroacupuncture analgesia]. 262 35


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