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)

Familial glucocorticoid resistance (FGR) is a rare hereditary disorder characterized by hypercortisolism and the absence of stigmata of Cushing's syndrome. The inability of glucocorticoids to exert their effects on target tissues is compensated for by increases in circulating corticotropin (ACTH) and cortisol, the former causing excess secretion of both adrenal androgens and adrenal steroid-biosynthesis intermediates with salt-retaining activity. There is considerable variability in the clinical presentations of FGR ranging from asymptomatic, to isolated chronic fatigue and to hypertension with or without hypokalemic alkalosis or to hyperandrogenism, or both. In women, hyperandrogenism can result in acne, hirsutism, menstrual irregularities, oligoanovulation, and infertility; in men it may lead to infertility and in children to precocious puberty. The reported molecular defects in FGR, such as point mutations and a microdeletion of the glucocorticoid receptor (GR) gene, cause partial resistance by, respectively, compromising the function of the GR or decreasing its intracellular concentration in glucocorticoid target tissues. Complete glucocorticoid resistance is believed to be incompatible with life in humans. Hence, the glucocorticoid resistance cases reported have been partial and of variable degree. The extreme variability in the clinical manifestations of the disorder can, additionally, be explained by differing sensitivity of target tissues to mineralocorticoids or androgens or both, and perhaps by different biochemical defects of the glucocorticoid receptor, causing selective resistance of certain glucocorticoid responses in specific tissues. Isolated tissue-resistance from a somatic mutation of the GR in a corticotropinoma from a patient with Nelson's syndrome was also found, suggesting that this may be a mechanism of tumorigenesis. There is additional evidence that defects of GR function can appear surreptitiously in a variety of clinical conditions, suggesting that glucocorticoid resistance in humans may be involved in the pathogenesis and/or clinical picture of a plethora of disease states, of which FGR is the archetype.
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PMID:Glucocorticosteroid resistance in humans. Elucidation of the molecular mechanisms and implications for pathophysiology. 782 90

The binding of hepatic lipase to rat liver was studied in an ex vivo perfusion model. The livers were perfused with media containing partially purified rat hepatic lipase or bovine milk lipoprotein lipase. The activity of the enzymes was determined in the perfusion media before and after passage through the liver. During perfusion with a hepatic-lipase-containing medium the lipase activity in the medium did not change, indicating that there was no net binding of lipase by the liver. In contrast, more than 80% of the lipoprotein lipase was removed from the medium. This lipoprotein lipase activity could be recovered into the perfusion medium completely by heparin perfusion of the liver. If livers, first depleted of hepatic lipase by heparin, were subsequent perfused with a hepatic-lipase-containing medium, 90 +/- 24 m-units of the lipase activity was bound per g of liver (up to 1000 m-units/total liver). However, heparin treatment of the liver decreases the ability of the liver to re-bind hepatic lipase by 80%. Perfusion of rat livers with 0.3 M NaCl released 60% of the lipase activity into the medium. Upon subsequent perfusion of these livers with hepatic-lipase-containing media, 541 +/- 164 m-units of hepatic lipase could be bound per g of liver (up to 5000 m-units/total liver). The binding of hepatic lipase was also studied in livers of corticotropin (ACTH)-pre-treated rats. In these rats also, hepatic lipase bound only to livers which had been pre-perfused with heparin or 0.3 M NaCl. After heparin pre-perfusion, 88 +/- 12 m-units of hepatic lipase could be bound per g of liver, similar to that with livers of control rats not treated with ACTH. After prior salt perfusion, however, the capacity of the livers of ACTH-pre-treated rats to bind hepatic lipase was 212 +/- 60 m-units/g of liver. This is less than in livers of control rats (541 +/- 164 m-units/g of liver). These results indicate that in rat liver the binding of hepatic lipase is heterogeneous in character and consists of heparin-resistant and heparin-sensitive components. The hepatic-lipase binding capacity of the liver is saturable and fully utilized under various conditions. The heparin-sensitive binding capacity is lowered in ACTH-treated rats, whereas the heparin-resistant binding is unaffected. We postulate that the functional hepatic lipase activity can be regulated by changes in the binding capacity of the liver.
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PMID:Rat liver contains a limited number of binding sites for hepatic lipase. 794 95

The restricted environmental stimulation technique or REST is a method of relaxation where the level of environmental sensory inputs is kept very low. A particular REST technique called tank flotation, or flotation REST, consists of 1 h sessions in a tank containing water with a high salt content and maintained at 35.5 degrees C. In this protocol, five normal subjects were studied before and during 2 h after a 60 min flotation REST session and a control session of 60 min in a supine position on a bed. Cortisol, thyreostimulating hormone (TSH), thyroxine (T4), prolactin, melatonin, luteinizing hormone (LH), growth hormone (GH), beta-endorphin, vasopressin (ADH), gamma-aminobutyric acid (GABA) and homovanillic acid (HVA) were measured in plasma. HVA, 5-hydroxy-indoleacetic acid (5-HIAA) and vanylmandelic acid (VMA) were measured in urine. There were no changes in hormones concentrations that could be attributed to flotation REST. The urinary excretion of VMA was lower after the flotation REST session. The psychological consequences of flotation REST were more easily demonstrated than the neuroendocrine changes that are assumed to reflect the state of relaxation. Flotation REST increased subjective levels of sedation and euphoria. The possible mechanisms by which flotation REST induces relaxation are discussed.
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PMID:Neuroendocrine and psychological effects of restricted environmental stimulation technique in a flotation tank. 800 91

The results of experiments on white rats, consuming different quantities of NaCl, show that excessive sodium chloride load increases osmolarity of blood plasma mainly due to excessive accumulation of Cl- in the blood. At the same time urine osmolarity increases by a factor of 10 due to the rise of water reabsorption and a fall in reabsorption of osmotical active substances such as sodium, potassium, chlorides, phosphates and other ions showing tendency to the glomerulus filtration rate rise. This testifies to the priority of osmoregulation over ionoregulation. NaCl injection causes a fall in difference of Na+ and Cl- concentrations in the blood plasma due to Na+ deposition by tissues, which leads to extracellular metabolic acidosis. Kidneys respond to it by a decrease of the urine pH and increase of excretion of hydrogen ions in the form of titrated acids and ammonium, as well as by removal of chloride ions which are not connected with sodium. The conclusion is made that kidneys' function of acid-excretion depends first of all on the acid-base status of extracellular fluids and not on intracellular pH. Concentration of corticotropin in the blood increases in the case of sodium deficiency as well as in the excess of sodium. Deficiency of Na+ intensifies activity of the renin-angiotensin-aldosterone system and decreases ADH secretion, while salt load produces just the opposite effect. The role of the hormones in kidneys' compensatory reaction to excessive NaCl load is discussed.
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PMID:[Response and endocrine mechanisms in the kidney effected by sodium chloride]. 804 19

Glucocorticoid resistance results from the partial, albeit apparently generalized, inability of glucocorticoids to exert their effects on target tissues. The condition is associated with compensatory increases in circulating pituitary corticotropin and cortisol, with the former causing excess secretion of both adrenal androgens and adrenal steroid biosynthesis intermediates with salt-retaining activity. The manifestations of glucocorticoid resistance vary from chronic fatigue (perhaps a result of glucocorticoid deficiency in the central nervous system) to various degrees of hypertension with or without hypokalemic alkalosis or hyperandrogenism, or both, caused by increased cortisol and other salt-retaining steroids and adrenal androgens, respectively. In women, hyperandrogenism can result in acne, hirsutism, menstrual irregularities, oligoanovulation, and infertility; in men, it may lead to infertility and in children, to precocious puberty. Different molecular defects, such as point mutations or a microdeletion of the highly conserved glucocorticoid receptor gene, alter the functional characteristics or concentrations of the intracellular receptor and appear to cause glucocorticoid resistance. The extreme variability in the clinical manifestations of glucocorticoid resistance and its mimicry of many common diseases can be explained by the overall degree of glucocorticoid resistance, differing sensitivity of target tissues to mineralocorticoids or androgens or both, and perhaps different biochemical defects of the glucocorticoid receptor, with selective resistance of certain glucocorticoid responses in specific tissues. The various different symptoms of classic glucocorticoid resistance and the theoretical potential of this condition to appear surreptitiously emphasize the importance of the glucocorticoid receptor in the pathogenesis of human disease.
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PMID:Syndromes of glucocorticoid resistance. 818 39

Previously, we showed that during salt-loading in mice there was an acute rise in plasma ACTH levels after 2 days followed by a transient decrease after 4 and 9 days. Pro-opiomelanocortin (POMC) mRNA levels in the anterior pituitary increased after 2 days and returned to normal thereafter. In this study, changes in hypothalamic CRH and AVP mRNA levels during salt-loading were investigated using quantitative in situ hybridization histochemistry. CRH mRNA was expressed only in the paraventricular nucleus (PVN), while AVP mRNA was expressed in both the supraoptic (SON) and paraventricular nuclei. CRH mRNA levels were unchanged after 2 days salt-loading, but declined to 77% of control levels after 9 days. AVP mRNA levels rose to 260% and 634% of control levels in the SON, and to 352% and 522% of control levels in the PVN, after 2 and 9 days salt-loading, respectively. These data suggest a major role of AVP in the acute stimulation of ACTH secretion and POMC mRNA levels seen after 2 days salt-loading. Desensitization of AVP receptors at the corticotroph level and a centrally mediated inhibition of CRH release may account for the decrease of ACTH secretion and POMC mRNA levels in the anterior pituitary with prolonged salt-loading.
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PMID:The effect of salt-loading on corticotropin releasing hormone and arginine vasopressin mRNA levels in the mouse hypothalamus: a quantitative in situ hybridization analysis. 824 54

Various doses of sulfated cholecystokinin octapeptide (CCK-8s) injected intracerebroventricularly (ICV) alone did not show any antinociceptive effect. CCK-8s (0.01-1 ng) pretreated ICV for 10 min dose-dependently attenuated the inhibition of the tail flick response induced by ICV-administered morphine (2 micrograms). beta-endorphin (1 microgram), and U50,488H (trans-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl) cyclohexyl]benzeocetamide), 60 micrograms). However, ICV pretreatment with CCK-8s was not effective in reducing the inhibition of the tail flick response induced by [D-Pen(2)-D-Pen5]enkephalin (DPDPE; 10 micrograms) administered ICV. To determine what subtype(s) of CCK receptors are involved in antagonizing the antinociception induced by these opioids, effect of lorglumide sodium salt (a CCKA receptor antagonist) or PD135,158 N-methyl-D-glucamine salt (a CCKB receptor antagonist) on opioid-induced inhibition of the tail flick response was examined. Various doses of lorglumide sodium salt (lorglumide) or PD135,158 N-methyl-D-glucamine salt (PD135,158) injected ICV alone did not affect the basal tail flick response. The antagonistic effect of CCK-8s on morphine-, beta-endorphin-, and U50,488H-induced inhibition of the tail flick response was blocked in a dose-dependent manner by the co-ICV injection of PD135,158 (0.001-0.1 ng). The co-ICV injection of lorglumide (0.001-0.1 ng) dose-dependently blocked the antagonistic effect of CCK-8s on beta-endorphin- and U50,488H-induced, but not morphine-induced, inhibition of the tail flick response. Our results suggest that both CCKA and CCKB receptors are involved in antagonizing antinociception induced by beta-endorphin and U50,488H administered supraspinally. However, only CCKB (but not CCKA) receptors are involved in antagonizing antinociception induced by morphine administered supraspinally. CCK receptors are not involved in antagonizing the supraspinally administered DPDPE-induced antinociception.
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PMID:Involvement of different subtypes of cholecystokinin receptors in opioid antinociception in the mouse. 854 43

The pituitary prohormone proopiomelanocortin gives rise to melanocortins of alpha, beta, and gamma primary structure in addition to corticotropin. Melanocortins have a variety of actions in mammals, and each is natriuretic. In particular, gamma-melanocyte-stimulating hormone has been shown to mediate reflex natriuresis after acute unilateral nephrectomy. We examined whether this peptide could play a role in longer term adjustments in sodium balance by measuring plasma gamma-melanocyte-stimulating hormone and corticotropin concentrations, as well as pituitary proopiomelanocortin mRNA abundance, in Sprague-Dawley rats ingesting either a low (0.07% NaCl) or high (7.5% NaCl) sodium diet. One week after the high sodium diet, plasma gamma-melanocyte-stimulating hormone concentration was double the value seen in rats on the low sodium diet (158 +/- 5 [SE] versus 76 +/- 9 fmol/mL, P < .001), a change that was accompanied by a fivefold increase in plasma atrial natriuretic peptide concentration but no change in plasma corticotropin. Whole pituitary proopiomelanocortin mRNA abundance, measured with a probe to exon 3 of the rat proopiomelanocortin gene, was significantly increased after 1 week of the high sodium diet compared with the low sodium diet and increased further at 2 and 3 weeks. This increase occurred primarily in the neurointermediate lobe as demonstrated by in situ hybridization; the content of gamma-melanocyte-stimulating hormone immunoreactivity was also increased in this lobe, but not the anterior lobe, after 1 week of the high sodium diet. These results demonstrate that high dietary sodium intake increases neurointermediate lobe proopiomelanocortin mRNA abundance compared with a very low sodium diet and also suggest that proopiomelanocortin is preferentially processed into gamma-melanocyte-stimulating hormone rather than corticotropin. These observations consequently raise the possibility of a role for this peptide hormone system in the adjustments to a high salt diet.
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PMID:Dietary sodium intake modulates pituitary proopiomelanocortin mRNA abundance. 870 89

To assess daily rhythms of salt appetite, we measured spontaneous 300 mM NaCl intake of male Sprague-Dawley rats fed a diet containing 150 or 25 mmol Ca2+/kg. Both groups drank most NaCl at night, but, as the dark period progressed, intakes of controls remained constant or diminished, whereas intakes of rats fed low-Ca2+ diet increased. During the late dark period, when the difference in NaCl intake between the two dietary groups was greatest, rats fed a low-Ca2+ diet lost more corticosterone and sodium in urine, had lower plasma osmolarity, and had higher plasma adrenocorticotropic hormone (ACTH) and corticosterone concentrations than did controls. Over the 24-h cycle, rats fed the low-Ca2+ diet excreted less Ca2+ and more corticosterone in urine than did controls. They also had consistently lower plasma concentrations of Ca2+ and renin activity and consistently higher plasma phosphorus, arginine vasopressin, parathyroid hormone, thyroxine, calcitonin, and 1,25-dihydroxyvitamin D3. These findings support the hypothesis that salt appetite induced by dietary Ca2+ deficiency involves a subtle dysfunction of the ACTH-corticosterone axis, but they also raise several other possibilities.
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PMID:Daily rhythm of NaCl intake in rats fed low-Ca2+ diet: relation to plasma and urinary minerals and hormones. 878 Feb 14

Exogenous glucocorticoid replacement in patients with congenital adrenal hyperplasia (CAH), who due to an adrenal 21-hydroxylase enzyme deficiency are unable to produce endogenous glucocorticoids, is aimed at normalizing hypothalamic-pituitary-adrenal function. Excess androgen production by the adrenals is thus decreased. Despite standard glucocorticoid replacement doses (12.5-40 mg, 10.5-27 mg/m2/day hydrocortisone equivalents) 4 of 7 patients ranging in age from 14 to 33 years had abnormalities of the pituitary on MRI. Three appeared to have microadenomas and 1 had an empty sella. Five (3 salt wasters, 2 simple virilizers) of these 7 patients had 60-min p.m. ovine corticotropin-releasing hormone (oCRH) stimulation studies. The mean (logarithm) area under the ACTH curve for 0-60 min after oCRH stimulation was significantly greater in patients than controls (p < 0.0001). Mean ACTH at each time point before and after oCRH stimulation was similarly greater in patients than controls (p < 0.05). Two of these patients had pituitary microadenomas, 1 had an empty sella; all 3 were salt wasters. Despite standard glucocorticoid replacement, adolescent and young adult patients with CAH tend to have high basal ACTH and ACTH hyperresponsiveness to oCRH, as well as structural abnormalities of the pituitary. The inevitable periods of under- and overexposure to glucocorticoids in CAH patients may over time cause abnormalities of the hypothalamic-pituitary-adrenal axis.
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PMID:Failure of steroid replacement to consistently normalize pituitary function in congenital adrenal hyperplasia: hormonal and MRI data. 880 8


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