Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The role of endothelin-1 (ET-1), a potent vasoconstrictor peptide secreted by endothelial cells, in fetal circulation was investigated in relation to fetal hypoxia. Umbilical venous blood was obtained from 23 subjects who delivered between 36 and 41 weeks of gestation. In all cases, pH of umbilical venous blood was measured immediately after the delivery of placenta. ET-1 was extracted from the umbilical venous plasma by an Amprep C2 column and determined by a specific radioimmunoassay. Immunoreactive ET levels in the umbilical cord plasma (pg/ml, mean +/- SEM) from subjects with umbilical venous blood pH levels below 7.30 (n = 9) were 12.53 +/- 2.03, significantly higher than those with pH levels above 7.30 (6.44 +/- 1.11, n = 14). These results indicate that ET-1 in the fetal circulation may be involved in the regulation of the circulation in response to changes in acid-base balance related to fetal hypoxia.
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PMID:Relationship between fetal hypoxia and endothelin-1 in fetal circulation. 172 27

The vasoconstrictor peptide endothelin-1 (8 x 10(-10) to 1 x 10(-8) mol/L) significantly increased fetal-placental perfusion pressure in vitro in a cumulative manner from 30 +/- 2 to 123 +/- 25 mm Hg (mean +/- SEM, n = 5, p less than 0.0005, analysis of variance). Accompanying this vasoconstriction was a corresponding reduction in fetal-placental perfusate flow rate. Measurement of thromboxane B2 and 6-keto-prostaglandin F1 alpha in the fetal-placental perfusate revealed a significant reduction in their release (p less than 0.0096 and p less than 0.0004, analysis of variance, respectively) when corrected for flow rate. Neither the thromboxane synthesis inhibitor dazoxiben (10(-6) mol/L) nor the thromboxane receptor antagonist SQ29548 (10(-6) mol/L) was able to block the vasoconstrictor actions of endothelin-1. Therefore endothelin-1-induced vasoconstriction in the human fetal-placental circulation does not appear to be mediated by thromboxane release or action. The stimulus to eicosanoid release in the fetal-placental circulation may be hydrodynamic, i.e., flow or shear stress.
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PMID:Endothelin-1-induced vasoconstriction is not mediated by thromboxane release and action in the human fetal-placental circulation. 175 Apr 66

The in vitro effects of endothelin-1 (ET-1) and endothelin-3 (ET-3) on the release of prostaglandin (PG)E2 from the rat median eminence were investigated. The addition of ET-1 from 10(-9) M to 10(-6) M stimulated PGE2 release in a dose-dependent manner (from 10.5 +/- 2.1 to 54.4 +/- 5.6 pg/ME fragment/30 min; mean +/- SEM, p less than 0.001). ET-3 also stimulated the release of PGE2 from 10(-7) M to 10(-5) M dose dependently (from 18.1 +/- 0.7 to 60.9 +/- 17.4 pg/ME fragment/30 min p less than 0.05). The time course effect of ET-3 (10(-6) M) showed that PGE2 release was stimulated within five minutes (control, 1.5 +/- 0.5; ET-3, 15.8 +/- 3.0 pg/ME fragment/5 min, p less than 0.01). These results suggest that ET-1 and ET-3 have some physiological effects on the rat median eminence.
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PMID:Endothelin-1 and endothelin-3 stimulate prostaglandin E2 secretion from the rat median eminence. 179 40

Male volunteers were exposed to +10 degrees C ambient temperature for 2 hours while they were sitting undressed. The levels of endothelin-1 and atrial natriuretic peptide were determined by radioimmunoassays. Control samples were obtained at thermoneutrality. The cold exposure resulted in lowering of the mean skin temperature (from 31.2 +/- 0.3 degrees C-22.6 +/- 2.5 degrees C, mean +/- SEM), which indicates that a marked vasoconstriction took place, as well as a decrease of the body heat content (by 11.2 +/- 0.7 kJ kg-1). However, plasma endothelin-1 levels did not change significantly during the exposure. Thus circulating endothelin-1 does not seem to be responsible for the vasoconstriction associated with cold air exposure. The plasma atrial natriuretic peptide levels exhibited a slight increase towards the end of the cold exposure. This finding is in accord with the notion that atrial natriuretic peptide might contribute to the diuresis frequently observed in the cold.
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PMID:Plasma levels of endothelin-1 and atrial natriuretic peptide in men during a 2-hour stay in a cold room. 183 49

The presence of immunoreactive (IR) endothelin, endothelin mRNA, and endothelin receptors in human brain and pituitary gland has been studied by RIA, Northern blot hybridization, and receptor assay. IR endothelin was detected in all five brain regions examined (cerebral cortex, cerebellum, brain stem, basal ganglia, and hypothalamus) (6-10 fmol/g wet wt) and spinal cord (22 +/- 6 fmol/g wet wt, n = 7, mean +/- SEM). Higher concentrations of IR endothelin were found in the pituitary gland (147 +/- 30 fmol/g wet wt). Fast protein liquid chromatographic analysis of the IR endothelin in pituitary gland showed a large IR peak in the position of endothelin-3 and a smaller peak in the position of endothelin-1, whereas IR endothelin in the hypothalamus and brain stem was mainly endothelin-1. Endothelin messenger RNA was detected by Northern blot hybridization in the pituitary but not in hypothalamus. The receptor assay showed that 125I-endothelin-1 binding sites were present in large numbers in all five brain regions but were much less abundant in the pituitary gland. Binding capacity and dissociation constant were 5052 +/- 740 fmol/mg protein and 0.045 +/- 0.007 nM in brain stem and 963 +/- 181 fmol/mg protein and 0.034 +/- 0.009 nM in hypothalamus. In the pituitary gland, there were two classes of binding sites for endothelin with dissociation constants of 0.059 +/- 0.002 nM (binding capacity = 418 +/- 63 fmol/mg protein) and 0.652 +/- 0.103 nM (binding capacity = 1717 +/- 200 fmol/mg protein). Endothelin-1, -2 and -3 were almost equipotent in displacing the binding (IC50 approximately 0.04 nM). These findings are in accord with the possibility that endothelin acts as a neurotransmitter, neuromodulator or neurohormone in man.
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PMID:Endothelin in human brain and pituitary gland: presence of immunoreactive endothelin, endothelin messenger ribonucleic acid, and endothelin receptors. 184 8

1. A radioimmunoassay has been developed for measuring endothelin-like immunoreactivity in human plasma using an antibody raised against endothelin-1 which also cross-reacts with big endothelin-1 and endothelin-2 but not endothelin-3. 2. The sensitivity of the assay was 1 fmol/tube with inter- and intra-assay coefficients of variation of 13% and 9%, respectively. Cross-reactivity with endothelin-3 and non-endothelin peptides was less than 1%. 3. Endothelin-like immunoreactivity was present in the plasma of hypertensive patients (n = 25) at a concentration of 5.7 +/- 0.5 pmol/l (mean +/- SEM), which was not significantly different from that of age-matched control subjects (5.1 +/- 0.5 pmol/l). At these levels, endothelin-1 is unlikely to function as a circulating hormone. 4. Within the normotensive group, the concentration of endothelin-like immunoreactivity in plasma was positively correlated with mean arterial blood pressure, but in hypertensive patients it showed a significant negative correlation.
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PMID:A sensitive radioimmunoassay measuring endothelin-like immunoreactivity in human plasma: comparison of levels in patients with essential hypertension and normotensive control subjects. 215 45

The possible production and role of endothelin in the gastrointestinal tract was investigated in rats by radioimmunoassay, Northern-blot hybridization, receptor assay using membrane preparations, and pharmacological study using gut strips. Endothelinlike immunoreactivity was detected in all regions (from stomach to colon) of the rat gastrointestinal tract (13-48 fmol/g wet tissue) including the mucosal layer of the ileum and colon (8.4 +/- 2.0 fmol/g wet tissue and 18.4 +/- 2.1 fmol/g wet tissue, respectively, mean +/- SEM; n = 5). Fast protein liquid chromatographic analysis of the endothelinlike immunoreactivity in jejunum, ileum, colon, and colon mucosa extracts showed peaks in the positions of endothelin-1 and endothelin-3. The presence of endothelin-1 messenger RNA was demonstrated by Northern-blot hybridization in the whole colon and pooled ileal and colonic mucosa, but not in the whole jejunum. Specific binding in the rat gastrointestinal tract was particularly high in the fundus of stomach, jejunum, ileum, and colon. In the ileum, many binding sites were found in the circular and longitudinal muscle layers, but few in the mucosal layer. Endothelin-1 and endothelin-3 caused contraction of rat stomach strips, rat colon, and guinea pig ileum. These findings indicate that endothelin is present in the rat gastrointestinal tract, perhaps produced by both vascular endothelial cells and mucosal epithelial cells, and can cause contraction of gastrointestinal smooth muscle. Thus, endothelin may have a physiological role in the control of gastrointestinal function.
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PMID:Endothelin in the gastrointestinal tract. Presence of endothelinlike immunoreactivity, endothelin-1 messenger RNA, endothelin receptors, and pharmacological effect. 217 72

Plasma concentration of immunoreactive endothelin-1 was measured by radioimmunoassay in 6 healthy subjects before and following cold pressor test by immersion of one fore-arm into ice-water. Mean (SEM) plasma endothelin-1 concentration rose from 1.2 (0.7) to peak value 8.4 (2.3) pg/ml in venous plasma from the immersed hand, and, reaching peak 2 minutes later, from 1.4 (0.5) to 4.6 (2.3) pg/ml in venous plasma from the contralateral hand. In 66 healthy control subjects, venous plasma concentration of endothelin-1 was 2.9 +/- 1.2 pg/ml (mean +/- SD). Exposure to cold is associated with raised blood levels of endothelin-1, which points to a relation between endothelin-1 and vasoconstriction associated with low temperature.
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PMID:Raised plasma endothelin-I concentration following cold pressor test. 219 May 53

Plasma concentrations of endothelin, a vasoconstrictor peptide released from vascular endothelial cells, have been measured by radioimmunoassay in 100 patients with diabetes mellitus and 19 healthy subjects. The plasma immunoreactive-endothelin concentrations were found to be greatly raised in the patients with diabetes (1,880 +/- 120 fmol/l, mean +/- SEM) compared with the healthy subjects (540 +/- 50 fmol/l, p less than 0.005). The elevation of immunoreactive-endothelin could not be explained by secondary changes in blood pressure or renal disease and did not correlate with the presence of diabetic retinopathy, duration of diabetes mellitus, fasting blood glucose or serum fructosamine. Fast protein liquid chromatographic analysis of the diabetic plasma immunoreactive-endothelin showed three forms, one in a very big molecular weight position, one intermediate and one in the position of endothelin-1 itself. No material appeared in the positions of endothelin-2 and 3. Chromatographic analysis of normal plasma showed only the big molecular weight peak while material in the endothelin-1, 2 or 3 positions was below detection. The elevation of endothelin in diabetic patients may be a marker of, and further exacerbate, their vascular disease.
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PMID:Elevated plasma endothelin in patients with diabetes mellitus. 219 88

Immunoreactive endothelin has been detected in 21 of 43 samples of breast cyst fluid (21 cases; 3.5 +/- 0.6 pmol/l, mean +/- SEM. Other 22 cases; not detectable, less than 0.5 pmol/l). Fast protein liquid chromatographic analysis of the immunoreactive endothelin of pooled breast cyst fluid showed two immunoreactive peaks; one in the void volume and the other in the position of endothelin-1. It is probable that endothelin-1 is produced by the epithelial cells lining breast cysts, but significance of the presence of endothelin-1 in breast cyst fluid remains to be elucidated.
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PMID:Endothelin-like immunoreactivity in human breast cyst fluid. 222 26


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