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)

Previous studies have demonstrated that abolition of the naloxone-stimulated increase in plasma LH levels is characteristic of hypothalamic dysfunction in experimental uremia. This study aimed to further characterize the nature of the defect in hypothalamic opiatergic mechanisms in experimental uremia. Specifically, we have tested the hypothesis that naloxone resistance was due to either opioid receptor dysfunction or diminished opioid peptide levels. Administration of naloxone (2 mg/kg, iv) to cannulated freely mobile rats confirmed previous observations that despite marked increases in plasma LH in control rats, plasma LH levels were unaffected in uremic male rats (P = 0.001 for group x time interaction). In a second experiment, morphine (2 mg/kg) or saline diluent was given quasi-continuously as small aliquots before each blood sample during the pulse studies of castrate mature male rats that had undergone either subtotal nephrectomy or sham operation. After the administration of morphine, uremic rats exhibited a 60% reduction in mean LH levels (14.9 +/- 1.4 vs. 6.0 +/- 0.7 ng/ml) attributable to a 42% reduction in LH pulse frequency (3.6 +/- 0.4 vs. 2.1 +/- 0.5 peaks/3 h) and a 60% reduction in LH pulse amplitude (4.7 +/- 0.5 vs. 1.9 +/- 0.3 ng/ml). The preservation of sensitivity to morphine despite complete naloxone resistance raised the alternate hypothesis of depletion of endogenous opiate peptide levels in the uremic hypothalamus. This hypothesis was tested by measuring the beta-endorphin content of the medial basal hypothalamus (MBH) in a rat beta-endorphin RIA. Rat MBH beta-endorphin content was not significantly altered specifically by either uremia or castration. We conclude, therefore, that naloxone resistance of plasma LH in experimental uremia is not due to either defects in opioid receptor function or reduced hypothalamic beta-endorphin content. Instead, we suggest that uremia may diminish the release of endogenous opioid peptides that interact with GnRH neurons from the MBH.
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PMID:Hypothalamic opioid mechanisms in experimental uremic hypogonadism. 213 74

Seven cases with uremia (6 men, 1 woman, mean age = 55.6 +/- 2.2 years) were studied with four combined hypothalamic releasing hormones (corticotropin-releasing hormone, CRH; luteinizing hormone-releasing hormone, LHRH; thyrotropin-releasing hormone, TRH; and growth hormone-releasing hormone, GHRH) for assessment of anterior pituitary functions. The mean basal levels of corticotropin (ACTH, 22.4 +/- 5.2 pg/ml), thyrotropin (TSH, 2.4 +/- 0.6 microU/ml), and follicle stimulating hormone (FSH, 26.0 +/- 3.4 mIU/ml) in uremic patients were not significantly different from those (34.0 +/- 3.5 pg/ml, 2.0 +/- 0.4 microU/ml, and 23.2 +/- 6.4 mIU/ml) of controls (5 men, 1 woman, mean age = 54 +/- 2.5 years), but the ACTH and TSH responses to the releasing hormones were significantly lower than those of the controls. The mean basal levels of luteinizing hormone (LH, 70.7 +/- 16.3 mIU/ml), cortisol (9.8 +/- 1.2 micrograms/dl) and prolactin (109.3 +/- 23.2 ng/ml) in uremic patients were significantly higher than those of normals (27.3 +/- 6.6 mIU/ml, 6.5 +/- 0.7 micrograms/dl and 15.7 +/- 3.4 ng/ml), while suppressed LH, cortisol and prolactin responses to the releasing hormones were observed in the uremic group. The mean basal growth hormone (GH) level in uremic patients (3.1 +/- 0.4 ng/ml) was not significantly different from that (2.8 +/- 0.7 ng/ml) of normals, but the GH response to the releasing hormones was significantly higher than that of controls. These results show pituitary dysfunction, such as blunted ACTH, TSH, LH and prolactin response, exists in uremic patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Anterior pituitary functions in patients with uremia tested by stimulation with four combined hypothalamic releasing hormones. 256 85

To identify factors that regulate the levels of immunoreactive digitalis-like substances (irEDLS) in body fluids, two studies were carried out. Plasma and urine levels of irEDLS were measured in uremic and normal subjects. Extracted material was fractionated (12 fractions) and assayed by digoxin radioimmunoassay. In four fractions, higher levels of irEDLS were found in uremic than in normal plasma. Urine from healthy subjects contained very high levels of irEDLS, but in urine collected from uremic patients irEDLS levels were similar to those in plasma. In another study, eight healthy subjects were given dexamethasone 1 mg orally and tetracosactide [an adrenocorticotropic hormone (ACTH) analogue] 0.25 mg i.v., on separate occasions. Dexamethasone suppressed the plasma and urine levels of cortisol and irEDLS. ACTH increased the levels of cortisol in plasma and urine, and of irEDLS in plasma. Taken together, these results support the hypothesis that irEDLS are of adrenal origin. However, decreased renal clearance, rather than increased production or release, may be the main cause of increased plasma levels of irEDLS in uremia.
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PMID:Immunoreactive endogenous digoxin-like substances: plasma levels are dependent on the hypothalamic-pituitary-adrenal axis for release and on kidney function for elimination. 750 14

In order to examine the role of endogenous opioid peptides on glucose metabolism in uraemic patients, plasma concentrations of beta-endorphin, glucose, insulin and C-peptide were determined before and during an oral glucose tolerance test (OGTT) in nine non-dialysed patients with chronic renal failure (CRF). The results are compared with those obtained in a group of age-matched normal subjects. In CRF patients, plasma beta-endorphin fasting values (16.0 +/- 1.9 pmol/l) were significantly higher than those of the controls (6.6 +/- 0.6 pmol/l) and significantly correlated with the degree of renal function impairment. After glucose load, plasma beta-endorphin in CRF patients tended to decline, whereas in normal subjects increased. The fasting and the mean OGTT plasma beta-endorphin values negatively correlated with insulin initial response to glucose, insulin and C-peptide mean OGTT values, but not with glucose OGTT mean values. Data indicate that chronic uraemia induces a significant increase in circulating plasma beta-endorphin levels, with a loss of opioid system responsiveness to glucose. The possibility that this hyper-endorphinism may have a biological importance at least as a contributory factor of impaired glucose tolerance in uraemia may be suggested.
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PMID:Plasma beta-endorphin levels and glucose tolerance in patients with chronic renal failure. 757 9

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

Chronic kidney disease (CKD) is associated with an increase in inflammatory cytokines and can result in cachexia with loss of muscle and fat stores. We previously demonstrated the efficacy of treating a model of cancer cachexia with ghrelin and a ghrelin receptor agonist. Currently, we examine a surgical model of CKD in rats, resulting in uremia and decreased accrual of lean body mass. Treatment with ghrelin and two ghrelin receptor agonists (BIM-28125 and BIM-28131) resulted in increased food intake and an improvement in lean body mass accrual that was related in part to a decrease in muscle protein degradation as assessed by muscle levels of the 14-kDa actin fragment resulting from cleaved actomyosin. Additionally, there was a decrease in circulating inflammatory cytokines in nephrectomized animals treated with ghrelin relative to saline treatment. Ghrelin-treated animals also had a decrease in the expression of IL-1 receptor in the brainstem and a decrease in expression of prohormone convertase-2, an enzyme involved in the processing of proopiomelanocortin to the anorexigenic peptide alpha-MSH. We conclude that ghrelin treatment in uremia results in improved lean mass accrual in part due to suppressed muscle proteolysis and possibly related to antiinflammatory effects.
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PMID:Ghrelin treatment of chronic kidney disease: improvements in lean body mass and cytokine profile. 1803 82

Total body irradiation (TBI) or partial body irradiation is a distinct risk of accidental, wartime, or terrorist events. Total body irradiation is also used as conditioning therapy before hematopoietic stem cell transplantation. This therapy can result in injury to multiple tissues and might result in death as a result of multiorgan failure. The hypothalamic-pituitary-adrenal (HPA) axis could play a causative role in those injuries, in addition to being activated under conditions of stress. In a rat model of TBI, we have established that radiation nephropathy is a significant lethal complication, which is caused by hypertension and uremia. The current study assessed HPA axis function in rats undergoing TBI. Using a head-shielded model of TBI, we found an enhanced response to corticotropin-releasing hormone (CRH) in vitro in pituitaries from irradiated compared with nonirradiated rats at both 8 and 70 days after 10-Gy single fraction TBI. At 70, but not 8 days, plasma adrenocorticotrophic hormone (ACTH) and corticosterone levels were increased significantly in irradiated compared with nonirradiated rats. Plasma aldosterone was not affected by TBI at either time point, whereas plasma renin activity was decreased in irradiated rats at 8 days. Basal and stimulated adrenal steroid synthesis in vitro was not affected by TBI. In addition, plasma epinephrine was decreased at 70 days after TBI. The hypothalamic expression of CRH messenger RNA (mRNA) and hippocampal expression of glucocorticoid receptor mRNA were unchanged by irradiation. We conclude that the hypertension of radiation nephropathy is not aldosterone or catecholamine-dependent but that there is an abscopal activation of the HPA axis after 10 Gy TBI. This activation was attributable at least partially to enhanced pituitary ACTH production.
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PMID:Effect of high-dose total body irradiation on ACTH, corticosterone, and catecholamines in the rat. 2114 49