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)

To investigate the activity of the endogenous opioid system in patients with insulin-dependent diabetes mellitus during ventilatory stress situations, we measured plasma beta-endorphin levels in six male and five female diabetic patients breathing against fatiguing inspiratory resistive loads. The patients had to generate with each inspiration an esophageal pressure (Pes) 80% of maximum until they were exhausted and could no longer develop target Pes. The loaded breathing run was repeated three times with a 1-min interval between each run. Duty cycle, tidal volume, and breathing frequency were constant in all tasks. For each run plasma beta-endorphin levels were measured, inspiratory effort sensation assessed using a modified Borg scale, and inspiratory muscle endurance evaluated by the length of time the task could be maintained (Tlim). A group of 11 sex-, age-, height-, and weight-matched healthy individuals served as control subjects. Tlim was significantly lower in the diabetic patients. Evaluating respiratory effort during the three test runs in control subjects at a time corresponding to the break point of loaded breathing in patients showed significantly lower Borg ratings in the control group than in the patient group. Baseline plasma beta-endorphin was significantly lower in the diabetic patients (10.6 +/- 2.1 versus 27.0 +/- 4.2 pg/ml, p < 0.01). Additionally, whereas resistive loaded breathing caused a further increase in plasma beta-endorphin concentration in the control group (p < 0.005), absolutely no increase was found in the diabetic patients. We conclude that the endogenous opioid system in insulin-dependent diabetic patients does not respond to stress caused by breathing against fatiguing inspiratory resistive loads.
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PMID:Endogenous opioid system during inspiratory loading in patients with type I diabetes. 823 72

We examined whether streptozotocin-induced diabetes can modulate beta-endorphin-induced antinociception in mice. While beta-endorphin administered i.c.v. produced a dose-dependent inhibition of the tail-flick response in both diabetic and non-diabetic mice, the antinociceptive response was greater in diabetic mice than in non-diabetic mice. The ED50 value of beta-endorphin administered i.c.v. in diabetic mice was significantly lower than that in non-diabetic mice. The antinociceptive effects of beta-endorphin administered i.c.v. in both diabetic and non-diabetic mice were significantly antagonized by s.c. administration of naltrindole, a selective delta-opioid receptor antagonist. beta-Endorphin administered i.t. also produced a dose-dependent antinociception in both diabetic and non-diabetic mice. However, the ED50 value of kappa-opioid receptor antagonist. On the other hand, the antinociceptive potency of DPDPE, a selective delta-opioid agonist, administered i.t. is significantly increased in diabetic mice, as compared with non-diabetic mice, whereas, the antinociceptive potency of U-50,488H, a kappa-opioid receptor agonist, administered i.t. is significantly less than in non-diabetic mice. These results suggest that diabetes may modulate beta-endorphin-induced antinociception differently at the spinal and supraspinal levels.
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PMID:Effect of diabetes on the antinociceptive effect of beta-endorphin. 837 94

To determine whether abnormalities of hypothalamic-pituitary-adrenal axis function occur in type I diabetes mellitus, corticotropin, cortisol, 17-hydroxyprogesterone (17-OHP), androstenedione (D4-A), dehydroepiandrosterone (DHEA), and DHEA sulfate (DS) levels were measured after an intravenous (IV) injection of 1 microgram/kg human corticotropin-releasing hormone (CRH) in diabetic adolescents and normal age-matched subjects. CRH produced a consistent increase in corticotropin blood levels that was comparable in the two groups. In contrast, both baseline and stimulated cortisol concentrations were greater in diabetic patients. Levels of 17-OHP increased after CRH administration, and the magnitude of increase was similar in all subjects. Stimulation with CRH determined an attenuated integrated DS response in diabetics compared with normal subjects with a different pattern of the hormone secretion, whereas no differences in D4-A concentrations were detected between the two groups. DHEA serum levels of subjects from both groups underwent similar changes following administration of CRH. In conclusion, patients with type I diabetes have a discrete response of adrenal steroids to CRH stimulation that appears to be independent of corticotropin secretion. This phenomenon might be related to a direct effect of insulin on enzyme systems involved in the biosynthetic pathway of adrenal steroids or, alternatively, to an intra-adrenal CRH/corticotropin mechanism acting on the adrenal cortex in a paracrine manner.
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PMID:Adrenal steroid and adrenocorticotropin responses to human corticotropin-releasing hormone stimulation test in adolescents with type I diabetes mellitus. 841 66

In the horse, adenomata of the pairs intermedia of the pituitary gland have been associated with the distinct clinical entity of Cushing's disease which arises largely as a result of excessive secretion of adrenocorticotropin (ACTH) or other proopiomelanocortin (POMC) peptides. Pars intermedia peptide secretion is under dopaminergic control and compounds such as pergolide or bromocriptine, which are dopamine agonists, can palliate the clinical signs. A variety of endocrinological abnormalities, relevant to both pathogenesis and diagnosis, may be demonstrated in equine Cushing's disease, including hyperadrenocorticism, peripheral insulin resistance and excessive POMC-peptide secretion from the pituitary gland. Preliminary studies on carbohydrate metabolism suggest that quantification of insulin activity may be a useful prognostic index in cases of equine Cushing's disease, and that insulin therapy of secondary diabetes mellitus may be indicated in some cases.
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PMID:Equine Cushing's disease. 848 40

Several hormonal alterations have been described in patients with chronic renal failure. However, there are few epidemiological studies on uremia-associated endocrine derangements, in particular in patients undergoing peritoneal dialysis (PD). A cross-sectional descriptive study was performed to assess the prevalence of hormonal dysfunctions affecting pituitary secretions in the whole population of patients in the PD unit of our hospital. The total population included 69 patients, 66 on continuous ambulatory PD and 3 on continuous cycling PD. There were 31 men and 38 women, the mean age was 55 years (range 23-82 years), and the mean duration of PD was 32 months (range 1-161 months). There were 27 (39.1%) patients with diabetes mellitus (7 type I and 20 type II). Clinical records were reviewed for hormonal alterations affecting the pituitary and its target glands. The whole population had available data on the pituitary-thyroid axis. The following diagnoses and prevalences were found: hypothyrotropic hypothyroidism 4 (5.8%), subclinical hypothyroidism 4 (5.8%), primary hypothyroidism 8 (11.6%), and low T3 syndrome 11 (15.9%). The remaining pituitary hormones were available in 20 patients. Hyperprolactinemia was found in 7 (35%) patients and abnormally increased growth hormone levels in 6 (30%). Gonadotropin levels were normal for the age of the women and showed a tendency to be increased in most of the men. Corticotropin levels were normal in all patients with available data. There was no relationship between the high prevalence of diabetes mellitus in our population and the remaining hormonal derangements found. These results suggest that there is a non-negligible prevalence of pituitary abnormalities in uremic patients undergoing PD.
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PMID:Pituitary dysfunctions in uremic patients undergoing peritoneal dialysis: a cross sectional descriptive study. 853 9

In rats, beta-endorphin (beta-END) and gamma-aminobutyric acid (GABA) suppress LH secretion by hypothalamic mechanisms involving the preoptic area (POA). Systemic injection of naloxone (NAL) increases LH secretion in male rats, an effect which can be prevented by coadministration of GABA agonists. Application of NAL into the POA of ovariectomized (ovx), progesterone substituted sheep modulates preoptic GABA release. These findings have been interpreted such that the endogenous opioids act via the preoptic GABAergic system to regulate LH release. To evaluate this hypothesis we implanted ovx rats with push pull cannula into the POA and measured GABA secretion prior to and during the preoptic application of either NAL or beta-END. Blood samples were collected to assess the effects of the drugs on LH secretion. In addition, ovx rats were substituted with estradiol (E2) to induce a negative feedback effect on LH release. Intrapreoptic application of beta-END caused a rapid decline of LH release in ovx rats which was completely reversible after termination of beta-END perfusion. Though LH levels were clearly suppressed, no change of GABA release in the POA was observed. During preoptic NAL perfusion both LH secretion and GABA release remained unaffected. Likewise, during beta-END perfusion into the POA of E2 treated rats neither LH nor GABA secretion changed. In contrast, NAL perfusion rapidly increased LH release but again this action of the opioidergic drug was not accompanied by alterations of GABA release. We conclude from these data: 1) Intrapreoptically applied beta-END inhibits LH release only in the absence of steroids. In turn, blockade of opioid receptors is effective only in the presence of steroids. Both findings indicate that in the POA opioidergic activity is low in ovx rats, but high during negative feedback of E2. 2) No changes of GABA secretion were observed during manipulations of the opioidergic tonus in the POA suggesting that both beta-END and GABA do not interact to regulate LH release. Thus, beta-END may directly inhibit the activity of GnRH neurons located in the POA or acts via a neurotransmitter other than GABA.
Exp Clin Endocrinol Diabetes 1995
PMID:The inhibitory effect of beta-endorphin on LH release in ovariectomized rats does not involve the preoptic GABAergic system. 853 61

As previously reported, activation of the adrenocorticotropic hormone (ACTH)-adrenal cortical axis in rats with insulin-dependent diabetes mellitus (IDDM) reduces their growth and circulating insulin-like growth factor-I (IGF-I) levels and induces a resistance to growth hormone (GH) and IGF-I. The studies reported herein were conducted to determine whether the pituitary and/or adrenal gland influence the changes in basal and GH-stimulated serum concentrations of IGF-binding proteins (IGFBPs) in rats with IDDM. Male rats were made diabetic by injections of streptozotocin. Intact nondiabetic (NonDb), diabetic (Db), hypophysectomized diabetic (HxDb), and adrenalectomized diabetic (AxDb) rats were injected twice daily with 50 micrograms porcine (p) GH or with 0.9% saline for 2 weeks following the surgeries. Changes in serum IGFBP concentrations were determined by Western ligand- or immuno-blot analysis. Neither IGFBP-5 nor -6 was detected in any of the treatment groups. Induction of IDDM increased serum concentrations of IGFBP-1 and -2 and reduced those of IGFBP-3 and -4. Although serum IGFBP-1 and -2 concentrations remained elevated in the HxDb rats compared with the NonDb controls, IGFBP-1 levels were reduced compared with those in the Db controls. Serum IGFBP-3 and -4 were reduced to levels below those in Db controls. Although IGFBP-3 and -4 concentrations were elevated to normal in AxDb rats, the IGFBP-2 concentration was increased above those in both NonDb and Db rats and the IGFBP-1 concentration was reduced. Administration of pGH increased serum IGFBP-4 concentrations in all groups and IGFBP-3 concentrations in all groups except the Db. In addition, pGH reduced the concentration of IGFBP-1 in HxDb rats and nearly abolished it in AxDb rats, but had no effect on IGFBP-1 concentration in NonDb or Db rats. Administration of corticosterone (B; 25 micrograms/ml of 0.9% saline drinking water) to AxDb rats restored Db-like profiles of all IGFBPs. The refractoriness of Db rats to pGH is associated with a failure of the hormone to elevate IGFBP-2 and -3 titers and to reduce those of IGFBP-1. Adrenal B production appears to be responsible for this resistance to GH. However, the elevated IGFBP-2 concentration in Db rats does not appear to be due to B or any other pituitary-controlled or -derived factors. Impaired growth was associated with substantially reduced IGFBP-3 concentrations and elevated IGFBP-1, whereas growth restoration was associated with the opposite changes.
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PMID:Regulation of insulin-like growth factor-binding proteins in rats with insulin-dependent diabetes mellitus. 853 61

Plasma beta-endorphin (beta-E) concentration was determined before, during, and after a standardized incremental exercise test to maximal capacity in eight type I diabetic patients and eight normal control subjects. Diabetic patients were studied under normoglycemic and hyperglycemic conditions in a single-blind random fashion to differentiate between the effects of acute hyperglycemia and of diabetes per se on the beta-E response to exercise. The perceived magnitude of leg effort elicited by exercise was evaluated using a category scale. Whereas plasma beta-E concentrations increased in control subjects with increasing workload, causing significantly higher beta-E levels at the end of exercise than at the beginning (P < .001), no such increase could be observed in the diabetic patients under normoglycemic and hyperglycemic conditions. In addition, baseline plasma beta-E concentrations were significantly lower in normoglycemic (P < .01) and hyperglycemic (P < .001) diabetic patients than in control subjects. Even during the recovery period, patients' beta-E levels remained significantly lower than those of control subjects. At submaximal levels of power output, the perceived intensity of leg effort was significantly higher in normoglycemic and hyperglycemic diabetic patients than in control subjects. We conclude that in type I diabetic patients, the ability of the endogenous opioid system to respond to exercise-induced stress is impaired under hyperglycemic and even under normoglycemic conditions. Considering the effect of endogenous opioids on stress tolerance, such changes may compromise exercise performance in diabetic patients.
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PMID:Defective endogenous opioid response to exercise in type I diabetic patients. 859 79

Correction of the obese state induced by genetic leptin deficiency reduces elevated levels of both blood glucose and hypothalamic neuropeptide Y (NPY) mRNA in ob/ob mice. To determine whether these responses are due to a specific action of leptin or to the reversal of the obese state, we investigated the specificity of the effect of systemic leptin administration to ob/ob mice (n = 8) on levels of plasma glucose and insulin and on hypothalamic expression of NPY mRNA. Saline-treated controls were either fed ad libitum (n = 8) or pair-fed to the intake of the leptin-treated group (n = 8) to control for changes of food intake induced by leptin. The specificity of the effect of leptin was further assessed by 1) measuring NPY gene expression in db/db mice (n = 6) that are resistant to leptin, 2) measuring NPY gene expression in brain areas outside the hypothalamus, and 3) measuring the effect of leptin administration on hypothalamic expression of corticotropin-releasing hormone (CRH) mRNA. Five daily intraperitoneal injections of recombinant mouse leptin (150 micrograms) in ob/ob mice lowered food intake by 56% (P < 0.05), body weight by 4.1% (P < 0.05), and levels of NPY mRNA in the hypothalamic arcuate nucleus by 42.3% (P < 0.05) as compared with saline-treated controls. Pair-feeding of ob/ob mice to the intake of leptin-treated animals produced equivalent weight loss, but did not alter expression of NPY mRNA in the arcuate nucleus. Leptin administration was also without effect on food intake, body weight, or NPY mRNA levels in the arcuate nucleus of db/db mice. In ob/ob mice, leptin did not alter NPY mRNA levels in cerebral cortex or hippocampus or the expression of CRH mRNA in the hypothalamic paraventricular nucleus (PVN). Leptin administration to ob/ob mice also markedly reduced serum glucose (8.3 +/- 1.2 vs. 24.5 +/- 3.8 mmol/l; P < 0.01) and insulin levels (7,263 +/- 1,309 vs. 3,150 +/- 780 pmol/l), but was ineffective in db/db mice. Pair-fed mice experienced reductions of glucose and insulin levels that were < 60% of the reduction induced by leptin. The results suggest that in ob/ob mice, systemic administration of leptin inhibits NPY gene overexpression through a specific action in the arcuate nucleus and exerts a hypoglycemic action that is partly independent of its weight-reducing effects. Furthermore, both effects occur before reversal of the obesity syndrome. Defective leptin signaling due to either leptin deficiency (in ob/ob mice) or leptin resistance (in db/db mice) therefore leads directly to hyperglycemia and the overexpression of hypothalamic NPY that is implicated in the pathogenesis of the obesity syndrome.
Diabetes 1996 Apr
PMID:Specificity of leptin action on elevated blood glucose levels and hypothalamic neuropeptide Y gene expression in ob/ob mice. 860 77

The effects of streptozotocin-induced diabetes on pituitary neuropeptides were studied. Substance P, dynorphin and beta-endorphin in both pituitary lobes and cholecystokinin and somatostatin in the neurointermediate lobe (NIL) were measured 4 weeks after streptozotocin treatment in adult male rats. There were significant decreases of substance P levels in both the anterior lobe (AL) and NIL, and of cholecystokinin, dynorphin and beta-endorphin in the NIL, whereas the dynorphin content in the AL increased, when values were expressed on a per-lobe basis. On a per-milligram-protein basis, however, only beta-endorphin in the NIL showed a significant decrease, while AL beta-endorphin and dynorphin were increased. Correlated with these changes were a drastic decrease in the serum insulin level and a marked increase in serum glucose and corticosterone levels. All these changes were reversible with insulin treatment. It is suggested that the decrease in NIL contents of neuropeptides demonstrated (except for beta-endorphin) might be due to mechanisms other than a change in synthesis.
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PMID:Pituitary contents of beta-endorphin, dynorphin, substance P, cholecystokinin and somatostatin in rats with streptozotocin-induced diabetes. 873 22


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