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)

1. Alterations in phosphofructokinase properties can be reproducibly seen in tissue extracts prepared and rapidly assayed after exposure of rat adipocytes to hormones. 2. Noradrenaline, corticotropin or isoprenaline (isoproterenol; beta-adrenergic agonist) decreased the activity measured with high fructose 6-phosphate concentrations (3--6 mM), but increased activity measured with lower concentrations of this substrate (0.3--0.9 mM). Noradrenaline decreased the Vmax. and the concentration of fructose 6-phosphate that gave half the Vmax.. 3. Insulin opposed the actions of noradrenaline and itself increased phosphofructokinase activity. 4. The effect of noradrenaline appeared to be exerted through a beta- rather than an alpha-type of adrenoceptor. 5. The effects of noradrenaline to decrease phosphofructokinase activity at high [fructose 6-phosphate] and to increase activity at low [fructose 6-phosphate] could be rapidly reversed in cells by addition of the beta-blocker propranolol. 6. The effect of noradrenaline seen at low [fructose 6-phosphate] could be abolished by homogenization of cells in buffer containing albumin or reversed by brief incubation of tissue extracts with albumin, suggesting that this effect of the hormone is due to the association of some ligand with the enzyme.
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PMID:Rapid modulation of adipocyte phosphofructokinase activity by noradrenaline and insulin. 621 52

The incorporation of [(32)P]P(i) into phosphatidylinositol by rat fat-cells was markedly increased in the presence of adrenaline. Phosphatidic acid labelling was also increased, but to a lesser extent. These effects are due to alpha(1)-adrenergic stimulation since they were unaffected by propranolol, blocked by alpha-blockers in the potency order prazosin<<phentolamine<yohimbine and mimicked by methoxamine. The alpha-adrenergic stimulation of phosphatidylinositol labelling did not require extracellular Ca(2+), which supports the hypothesis that an increased turnover of phosphatidylinositol is involved in alpha-adrenergic activation of Ca(2+) entry. Insulin and the ionophore A23187 gave a small increase in (32)P labelling of phosphatidylinositol in Ca(2+)-free medium containing 1mm-EGTA. The increases due to insulin or ionophore A23187 were abolished if 2.5mm-Ca(2+) was added to medium containing EGTA. However, the increases in labelling of phosphatidylinositol due to alpha-adrenergic amines were still evident in medium containing EGTA and Ca(2+). Lipolytic agents such as corticotropin, dibutyryl cyclic AMP, adrenaline in the presence of phentolamine and isoproterenol decreased [(32)P]P(i) incorporation into phosphatidylinositol, phosphatidylethanolamine and phosphatidic acid. This inhibitory effect may be secondary to accumulation of intracellular unesterified fatty acids, since it was decreased by incubating fewer cells in medium with 6 rather than 3% albumin and was restored by the addition of oleate to the medium. The incorporation of [(32)P]P(i) into phosphatidylcholine was unaffected by lipolytic agents. The data suggest that there is an inhibition of the synthesis of certain phospholipids in the presence of lipolytic agents, which may be secondary to intracellular accumulation of unesterified fatty acids.
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PMID:Effect of insulin, catecholamines and calcium ions on phospholipid metabolism in isolated white fat-cells. 624 61

Since plasma ACTH, beta-lipotropin [beta-LPH-(1-91)], gamma-lipotropin (gamma-LPH: [beta-LPD-(1-58)]), and beta-endorphin (beta-EP: [beta-LPH-(61-91)]) are all derived from a common precursor molecule, their quantification in the same plasma under basal and stimulatory conditions should help to elucidate factors involved in their secretion and regulation. A sequential immune affinity chromatographic procedure was used to separate immunoreactive beta-LPH, gamma-LPH, and beta-EP on individual patient samples. Basal morning plasma concentrations [femtomoles per ml (to convert values to picograms per ml, femtomoles per ml values are multiplied by 10 for beta-LPH, by 5.8 for beta-LPH, by 4.5 for ACTH, and by 3.4 for beta-EP; n = 19; mean +/- SEM)] were: beta-LPH, 6.1 +/- 0.8; gamma-LPH, 4.4 +/- 0.5; and ACTH, 11.1 +/- 1.3. beta-EP was undetectable (< 1.5 fmol ml-1) in 7 of the 19 basal samples. The mean +/- SEM for the 12 remaining samples was 2.3 +/- 0.2. Insulin-induced hypoglycemia and Pitressin administration were associated with nearly equivalent increments of immunoreactive ACTH and beta-LPH concentrations. The resolving power of the technique was tested by separately applying the immunoreactive beta-LPH, gamma-LPH, and beta-EP fractions obtained from plasma pools to Sephadex G-50 gel filtration for molecular weight estimation. Greater than 88% of all immunoreactive material eluted with a Kav similar to the appropriate standard peptide markers. This immune affinity chromatographic system, therefore, permits simultaneous quantification of these peptides on small plasma volumes more rapidly and with greater resolution than when molecular sieve chromatography is used as an adjunct to RIA.
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PMID:Simultaneous determination of human plasma immunoreactive beta-lipotropin, gamma-lipotropin, and beta-endorphin using immuno-affinity chromatography. 625 27

ACTH and lipotropins (beta- and gamma-LPH) are synthesized from a common precursor by the pituitary corticotropic cell. We have measured LPH plasma levels under physiological and pathological conditions and we have compared them with ACTH plasma levels in the same circumstances. Spontaneous variations (nycthemeral rhythm) in LPH, ACTH and cortisol plasma levels were parallel, while responses to Dexamethasone freination test and stress (Insulin induced hypoglycemia) or more specific stimulation (Metopirone, lysine-vasopressin) were parallel and superimposable. LPH levels were always higher than ACTH levels in two pathological circumstances: chronic renal failure and Cushing's syndromes with ectopic ACTH producing tumors. The determination of both ACTH and LPH levels assists the diagnosis of corticotropic insufficiency and etiologic investigation of Cushing's syndrome, after hypercorticolism had been established. Although unable to confirm the presence of corticotropic adenoma in patients with Cushing's disease, or the predict effectiveness of pituitary surgery, these determination bring good arguments for treated Cushing's diseases follow up.
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PMID:[ACTH, beta-endorphin and lipotropins: physiopathological studies in man (author's transl)]. 628 91

Several alterations are present in the hypothalamic hypophyseal regulation of many hormones in patients with chronic renal failure. Evaluation of the hypothalamic hypophyseal adrenal axis in these groups of patients demonstrated normal levels of plasma cortisol. Dexamethasone suppression is abnormal after administration of 1 mg of oral dexamethasone, but normal after 3 mg. Dexamethasone blood levels were lower than the control after administration of 1 mg of oral dexamethasone. A dexamethasone metabolic clearance showed a similar half-life between the patients and controls. Oral absorption study showed poor absorption of the drug. Therefore, there is a problem of gastrointestinal absorption producing the abnormal dexamethasone suppression test in patients with renal failure. Results of metyrapone tests were normal. Corticotropin stimulation tests elicited a normal response. Insulin-induced hypoglycemia does not produce an increment in plasma cortisol or adrenocorticotropic hormone levels.
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PMID:Evaluation of the hypothalamic hypophyseal adrenal axis in patients receiving long-term hemodialysis. 628 45

Six normal subjects were studied to investigate the mechanisms involved in the release of immunoreactive beta-endorphin (ir-beta EP) in response to insulin hypoglycaemia. Insulin alone (0.2 U/kg body weight) was followed after a 30 min lag period by a congruent to 2.5 fold elevation of plasma ir-beta EP, with a return to basal levels by 90 min. Concurrent infusion of 10% dextrose at 250 ml/h for 2 h prevented the increase in plasma ir-beta EP levels, suggesting an effect of hypoglycaemia rather than a direct effect of insulin. Premedication with atropine 0.6 mg at -30 min was followed by hypoglycaemia equivalent to that seen with insulin alone, but no increase in plasma ir-beta EP, suggesting the involvement of cholinergic mechanisms in the neural mediation of ir-beta EP release in response to hypoglycaemia.
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PMID:Insulin hypoglycaemia and cholinergic blockade: response of plasma immunoreactive beta-endorphin. 631 63

In isolated adipocytes, fast-acting lipolytic hormones and insulin have been shown previously to control lipolysis by regulating the activity of hormone-sensitive lipase, the rate-limiting enzyme, through an increase or decrease, respectively, of the extent of phosphorylation of the enzyme. Here, we demonstrate that exposure to lipolytic hormones (corticotropin, noradrenaline) led to phosphorylation at two sites on the Mr 84,000 lipase subunit. One, designated "basal site," was phosphorylated also in the absence of any hormonal stimulation, its phosphorylation apparently not being influenced by hormones. The second, designated "regulatory site," was identical to that phosphorylated by cyclic AMP-dependent protein kinase on the isolated lipase. The regulatory site was not appreciably phosphorylated in the absence of hormones, but exposure of the cells to noradrenaline increased its phosphorylation extent to that of the basal site. Insulin or the beta-adrenergic antagonist propranolol decreased the extent of phosphorylation of the regulatory site to the low level before stimulation, apparently without effect on the basal site. Phosphoserine was the only phosphorylated amino acid residue at both sites. Limited proteolytic digestion indicated that the two sites were separated by less than about 170 amino acid residues. Thus, control of adipose tissue lipolysis by fast-acting lipolytic hormones and by insulin is exerted through the regulation of the phosphorylation state of a single phosphoserine residue in the hormone-sensitive lipase.
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PMID:Hormonal regulation of hormone-sensitive lipase in intact adipocytes: identification of phosphorylated sites and effects on the phosphorylation by lipolytic hormones and insulin. 637 55

The effect of chronic treatment with recombinant human erythropoietin (rHuEPO) on pituitary-adrenal axis responses to stress in patients undergoing continuous ambulatory peritoneal dialysis (CAPD) is not known. The purpose of this study was to assess the influence of rHuEPO treatment on corticotropin (ACTH) levels and cortisol responses to insulin-induced hypoglycemia in CAPD patients. Nine clinically stable and well-nourished patients (age 19-59 years) treated with subcutaneous rHuEPO, 34-208 U/kg BW/week, during 6-25 months were studied. Nine patients matched for age, sex, and duration of CAPD and not previously treated with rHuEPO were studied as the control group. Crystalline insulin (0.1 U/kg BW) was injected IV to the fasting subjects. Blood samples were collected before and 15, 30, 60, 90, and 120 minutes after insulin administration. In all blood samples serum cortisol and glucose concentrations were assessed. There were no statistically significant differences between both groups in hematocrit values and blood hemoglobin concentrations. Insulin administration induced a decrease in glucose levels that reached a nadir at 30 minutes in both groups (1.8 +/- 0.1 mmol/L in the rHuEPO group vs 2.1 +/- 0.2 mmol/L in the control group). After hypoglycemic stimuli cortisol levels clearly rose in rHuEPO-treated patients reaching a peak of 720 +/- 71 nmol/L at 60 minutes. However, in the control group the cortisol peak, which was not different from that observed in the rHuEPO group (676 +/- 44 nmol/L), occurred at 90 minutes. The areas under the secretory curve of cortisol did not differ between groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Influence of recombinant human erythropoietin treatment on cortisol responses to insulin-induced hypoglycemia in CAPD patients. 810 58

Insulin-like growth factor-II (IGF-II) gene expression is induced by adrenocorticotropic hormone (ACTH) in human fetal adrenals (HFA), which suggests an important role for IGF-II in HFA growth and differentiation. Many cytokines have different regulatory actions in the endocrine glands. In the present study we have investigated the effects of two cytokines, tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), on the regulation of IGF-II gene expression in cultured HFA cells. Both TNF-alpha and IFN-gamma inhibited basal and ACTH-induced accumulation of IGF-II mRNA dose-dependently. Cell viability was not altered by treatment with TNF-alpha or IFN-gamma. In addition, the combination of TNF-alpha and IFN-gamma decreased ACTH-induced IGF-II mRNAs more potently than each cytokine alone. Our results suggest that TNF-alpha and IFN-gamma may be involved in the regulation of HFA growth and differentiation via local IGF-II production.
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PMID:Tumor necrosis factor-alpha and interferon-gamma inhibit insulin-like growth factor II gene expression in human fetal adrenal cell cultures. 838 14

Hyperandrogenism, insulin resistance, and obesity are common features of polycystic ovarian syndrome (PCOS). This study was designed to investigate the relationship among these factors and how they might contribute to ovulatory dysfunction in PCOS. Adrenal androgen secretion and insulin resistance were quantified in oligomenorrheic women with PCOS and in three groups of eumenorrheic women: weight-matched hirsute women, obese nonhirsute women, and thin nonhirsute women. Adrenal androgen secretion was defined as the androstenedione response to synthetic corticotropin. Insulin resistance was estimated by calculating the area under the curve for serum insulin levels in response to a 75 g oral glucose load. The mean serum androstenedione response (nmol/L) to corticotropin in PCOS (5.6 +/- 1.3) was greater than that in eumenorrheic hirsute women (3.4 +/- 0.5; P < 0.10), obese nonhirsute women (1.8 +/- 0.8; P < 0.05), and lean nonhirsute women (1.9 +/- 0.5; P < 0.05). The serum androstenedione response was not correlated with body mass index (BMI). The area under the curve for serum insulin (mU/L.min/1000) in PCOS (29.1 +/- 5.3) was greater (P < 0.001) than in eumenorrheic hirsute women (9.1 +/- 1.7), obese nonhirsute women (5.8 +/- 1.0), and lean nonhirsute women (4.5 +/- 0.4). The serum insulin response was highly correlated with BMI (P < 0.001) in the three groups of obese women, but women with PCOS became significantly more insulin resistant with increasing BMI (P < 0.02). There was no correlation between adrenal androgen secretion and insulin resistance in any of the groups. We conclude that adrenal hyperandrogenism and insulin resistance are independent predictors of anovulation in hirsute women. These conditions are present in both oligomenorrheic and eumenorrheic hirsute women, but are present to a greater extent in anovulatory women. Obese women with PCOS also differ from eumenorrheic controls by developing a greater degree of insulin resistance as body mass increases.
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PMID:The role of adrenal hyperandrogenism, insulin resistance, and obesity in the pathogenesis of polycystic ovarian syndrome. 838 5


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