Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Persons participating in a 5-day diagnostic protocol were routinely typed for ABO, Rh, MNS, Kell, Kidd, Duffy, P, Haptoglobin, phosphoglucomutase-1 (PGM-1), and acid phosphatase (AcP). The study population was composed of 164 normotensive whites, 34 normotensive blacks, 161 whites and 43 blacks with essential hypertension, and 52 whites with secondary forms of hypertension (18 atherosclerotic renovascular hypertensives, 17 patients with fibromuscular disease, and 17 patients with primary aldosteronism). There were no significant differences in phenotype frequencies in ABO, Rh, Kidd, Kell, Duffy, P, Haptoglobin, PGM-1 or AcP in any of the comparisons. However, there was a significantly different distribution of MNS phenotypes in comparisons of essential and atherosclerotic renovascular hypertensives with normotensive controls. Essential hypertensives had a lower frequency of the S gene and a higher frequency of s in whites (X2 = 12.21, p less than 0.005). Atherosclerotic renovascular hypertensives differed from the normotensive population in the frequencies of both MN (X 2 = 4.34, p less than 0.05) and Ss (X2 = 4.21, p less than 0.05). The finding of disease-blood group associations supports the hypothesis that there may be significant physiological differences between individuals of different blood types.
Hypertension
PMID:Association of blood groups with essential and secondary hypertension. A possible association of the MNS system. 16 54

Ouabainlike factor (OLF) has been extracted from the hypothalamus and adrenals of the ox and rats of the Milan hypertensive strain (MHS) and their normotensive controls (MNS). OLF was identified by its ability to 1) inhibit ouabain-sensitive 86Rb uptake into human erythrocytes, 2) displace [3H]ouabain binding, and 3) inhibit purified dog kidney Na-K-adenosinetriphosphatase (ATPase). Rat and bovine OLF have similar characteristics. Those that are close to ouabain are 1) ligand conditions for maximal inhibitory activity, 2) high-performance liquid chromatography retention time, 3) reversibility of inhibitory activity on Na-K-ATPase, 4) reduced Na-K pump inhibitory activity by K, 5) high affinity for Na-K-ATPase, and 6) no activity on calcium ATPase. OLF does not resemble ouabain in the following characteristics: 1) the capacity of OLF to inhibit ouabain low-affinity Na-K-ATPase isoform is greater than that of ouabain and 2) the capacity of OLF to inhibit renal Na-K-ATPase isoforms is greater when the enzyme is obtained from adult rather than young rats. The yield of OLF is greater from MHS than MNS. These findings represent the first direct evidence that a higher amount of OLF is present in tissues from genetically hypertensive rats than from their inbred normotensive controls, maintained under the same dietary and environmental conditions. This further supports previous observations on the role of OLF in the pathogenesis of MHS hypertension.
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PMID:Ouabainlike factor in Milan hypertensive rats. 132 60

A series of compounds related to torasemide, a loop diuretic, were synthesized and examined for their diuretic potency and inhibitory activity on the erythrocyte and renal medullary thick ascending limb vesicle Na+,2Cl-,K+ cotransport in Milan hypertensive (MHS) and normotensive (MNS) rat strains, where previous studies had demonstrated an alteration of the cotransport system genetically related to hypertension. From the results of the screening, structure-activity relationships were drawn and two compounds, JDL 961 and C 2921 were selected. Their IC50 on renal vesicle cotransport were similar in the two strains (JDL 961: MHS = 1.8 microM; MNS = 1.2 microM; C 2921: MHS = 4 microM; MNS = 3.8 microM), and were 4-8 times lower than those of torasemide (MHS = 13 microM; MNS = 31 microM, P less than 0.01) and 50-60 times lower than those of bumetanide (MHS = 145 microM; MNS = 206 microM, P less than 0.05) taken as reference compounds. Their ability to reduce the development rate of hypertension was tested both in MHS and in Okamoto spontaneously hypertensive rats (SHR) strain, in which cotransport alterations are opposite to those of MHS. Both torasemide derivatives (7.5 mg.kg-1 os per day) prevented development of hypertension in the two strains. The time course of this hypotensive activity was faster and the percentage of blood pressure fall greater in MHS (20-25%) than in SHR rats (12-15%), even though the absolute value of blood pressure fall was similar in MHS (JDL 961 = -17 mm Hg; C 2921 = -30 mm Hg) and SHR (JDL 961 = -25 mm Hg; C 2921 = -20 mm Hg). A superimposable effect of bumetanide was observed in the two strains, but at 8 times higher daily dose (60 mg.kg-1). These results suggest that new loop diuretics can be selected for their antihypertensive activity on the basis of their in vitro potency in inhibiting the Na+,2Cl-,K+.
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PMID:Na+,2Cl-,K+ cotransport system as a marker of antihypertensive activity of new torasemide derivatives. 142 67

The (Na+,K+)-ATPase activity from the kidney cortex of the Milan hypertensive rat strain (MHS) and the corresponding normotensive control (MNS) was measured both in active solubilized enzyme preparations and in isolated basolateral membrane vesicles. Kinetic analysis of the purified enzyme showed that the Vmax value was significantly higher in MHS rats. The difference between MHS and MNS was not linked to a different number of sodium pumps, but was related to the molecular activity of the enzyme. Using basolateral membrane vesicles, an increased ATP-dependent ouabain-sensitive sodium transport was also demonstrated in MHS rats. These results support the hypothesis that a higher tubular sodium reabsorption may be involved in the pathogenesis of hypertension in this rat strain.
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PMID:Increased Na pump activity in the kidney cortex of the Milan hypertensive rat strain. 165 32

Environmental factors, genetic polymorphism and differences in experimental design have been the main impediments to evaluating the evidence for a genetic association between cell membrane cation transport abnormalities and human essential or genetic hypertension. The present paper reviews the results obtained in the Milan hypertensive rat (MHS) and in its corresponding normotensive strain (MNS) in order to illustrate our approach to defining the role of cation transport abnormality in a particular type of genetic hypertension. Kidney cross-transplantation between the strains showed that hypertension is transplanted along with the kidney. Proximal tubular cell volume and sodium content were lower in MHS rats while sodium transport across the brush border membrane vesicles of MHS rats was faster. Erythrocytes of MHS rats have a smaller volume, faster Na,K cotransport and a lower Km for internal sodium compared with MNS rats. The faster cotransport is also present in renal cells of the ascending limb and in vascular muscle cells. Moreover, these erythrocyte abnormalities are genetically associated in F2 hybrids and are primarily determined in the stem cells. These differences in ion transport between MHS and MNS rats are not present when studied in erythrocyte inside-out vesicles, which are deprived of membrane skeletal proteins, suggesting that a molecular abnormality underlies the functional one. We have identified a point mutation of one of these cytoskeletal membrane protein adducin genes in MHS rats. At present we are evaluating the possibility that mutation of the adducin gene in MHS rats might account for the differences in ion transport and, therefore, in blood pressure between the two strains.
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PMID:Genetic aspects of ion transport systems in hypertension. 171 Feb 65

Human arterial hypertension is likely a multifactorial trait resulting from multiple measurable monogenes, blended polygenes, shared family environment, and individual environment. Familial aggregation of hypertension and familial correlation of blood pressure appears to be more due to genes than to shared family environment. Total genetic heritability of 80% with some recessive major gene effects have been found for several traits associated with hypertension including urinary kallikrein excretion, intraerythrocytic sodium, and sodium-lithium countertransport. Other interesting factors regarding hypertension genetics include: non-modulation of the renin angiotensin system, intralymphocytic sodium, ionized calcium, and several genetic markers such as haptoglobin, HLA, and MNS blood type. Probably the most clinically useful information regarding the genetics of hypertension is evolving in several studies reporting a strong association of hypertension with dyslipidemia, diabetes, and obesity.
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PMID:Genetics of hypertension: what we know and don't know. 220 56

This paper describes experiments to examine Rb+ fluxes via the Na+/K+/Cl- cotransporter in membrane vesicles from renal outer medulla of three strains of rat: (A) Wistar (B) Milan hypertensive (MHS) and normotensive (MNS), and (C) Sabra salt-sensitive hypertensive (SBH) and salt-resistant (SBN). Initially, Na(+)-dependent furosemide- or bumetanide-inhibited 86Rb+ fluxes were characterised using Wistar rat microsomes. The latter were partially purified on a metrizamide cushion, and assay conditions were optimized for use with microsomes from the other rats. The major result is that in microsomes from adult Milan hypertensive (MHS) rats the rate of the Na+/K+/Cl(-)-cotransporter mediated 86Rb flux at sub-saturating concentrations of Rb, appears to be significantly greater than in the normotensive (MNS) controls. The effect reflects an increased apparent Rb affinity of the cotransporter in MHS microsomes. There is no difference in maximal rate or in the apparent Na+ activation affinity of the 86Rb+ flux. In addition bumetanide appears to be a somewhat more effective inhibitor in MHS compared to MNS microsomes. The 86Rb+ flux result is compatible with a previous finding that in red cells, Na+/K+ -cotransporter mediated fluxes are increased in MHS compared to MNS. It supports the notion that the Na+/K+/Cl(-)-cotransporter in in both red cells and kidney is a genetic marker for hypertension. It is of interest that apparently more than one Na+ transport system is affected in MHS hypertensive kidneys (a) the Na+/K+/Cl- cotransporter in the thick ascending limb of Henle and (b) the Na+/H+ exchanger and/o a conductive Na(+)-pathway in brush-border membranes from proximal tubule. It is conceivable that in the hypertensive animals a common regulatory pathway (e.g., phosphorylation) or protein (e.g., cytoskeleton) is affected along the length of the nephron. In Sabra SBH and SBN rat microsomes, no difference was found for the 86Rb+ flux via the Na+/K+/Cl- cotransporter (or via a K+ channel).
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PMID:Na+/K+/Cl(-)-cotransporter mediated Rb+ fluxes in membrane vesicles from kidneys of normotensive and hypertensive rats. 229 62

An approach to evaluating the genetic components of essential hypertension using an animal model, the Milan hypertensive strain (MHS) of rats, and studies in human families with positive and negative histories for high blood pressure are described and discussed. Differences at renal and cellular levels between MHS and its normotensive control strain, MNS, show many similarities to those between offspring from hyper- and normotensive families in humans. These include, with respect to the former group of each species, lower erythrocyte volume and Na content, higher Na-K cotransport across red blood cell (RBC) membranes higher Na excretion after load, and greater pressor effect in transplanted kidneys. A novel protein found in rat RBC cytoskeleton appears to have a function in Na-K cotransport and it may, eventually, be possible to demonstrate in man.
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PMID:Renal abnormalities at the prehypertensive stage of essential hypertension. 246 5

Previous studies have shown that erythrocytes from the Milan hypertensive strain of rats (MHS) differ from erythrocytes from the control normotensive strain (MNS). These differences are determined within the stem cells, are genetically associated with the development of hypertension, and are similar to those found between the tubular cells of the two strains. Moreover they seem to be dependent upon the presence of the membrane skeleton proteins. In this paper we describe our studies aimed at identifying some precise protein difference between the membrane skeletons of the two strains, which may cause the cellular differences described above. Milan hypertensive strain and MNS rats were immunized with ghost or membrane skeleton extracts prepared from the other or their own strains. Only MHS rats immunized with MNS ghost or membrane skeleton extracts produced an antibody against a 105 KD protein in about 95% of the animals. This protein has been identified with the recently described cytoskeletal protein adducin on the following bases: the protein binds calmodulin (CaM) and protein kinase C (PKc) in a Ca2+ dependent way. It also binds phosphatidylserine, is the substrate of exogenous PKc, and finally it is purified by high salt extraction of Triton-X100 insoluble erythrocyte cytoskeletons followed by affinity chromatography on CaM-sepharose. Using this antibody the isolation from a mouse spleen library, the characterization and sequencing of a partial cDNA clone coding for this protein has been carried out. In conclusion adducin may be considered a very useful tool to test the hypothesis that the cellular differences between MHS and MNS may be caused by a difference in a membrane skeleton protein.
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PMID:Erythrocyte adducin differential properties in the normotensive and hypertensive rats of the Milan strain. Characterization of spleen adducin m-RNA. 270 90

Cerebral and renal alpha-adrenergic receptors play an important role in the control of blood pressure. We studied alpha-adrenergic receptors in the cerebral and renal cortex of Milan hypertensive strain (MHS) and normotensive strain (MNS) rats, a genetic model of spontaneous hypertension linked to a kidney abnormality. Binding of the selective alpha 1-adrenergic antagonist [3H]prazosin and the alpha 2-adrenergic antagonist [3H]rauwolscine was used for receptor studies in tissues of prehypertensive (24-day-old) and hypertensive (60-day-old) rats. In the cerebral cortex, no between-strain differences in alpha 1-adrenergic and alpha 2-adrenergic receptor density and affinity were observed in prehypertensive and hypertensive periods. The density of these receptors increased similarly with age in MHS and MNS rats. In the renal cortex, the differences between MHS and MNS rats concerned alpha 2-adrenergic receptors only. Compared with their age-matched normotensive controls, MHS rats showed 1) a lower affinity for the antagonist (p less than 0.05) in the prehypertensive period, 2) absence of the normal age-related increase in receptor density, and 3) a lower density of [3H]rauwolscine binding sites (p less than 0.001) in the hypertensive period. In this period, studies of competitive inhibition of [3H]rauwolscine binding showed that l-epinephrine bound to one class of sites in MHS rats (pseudo-Hill plot, 0.90) and to two classes in MNS rats (pseudo-Hill plot, 0.68). In addition, the lack of any guanylylimidodiphosphate effect on the l-epinephrine competition curve observed in MHS rats suggests the uncoupling of these receptors from the guanosine 5'-triphosphate binding protein.(ABSTRACT TRUNCATED AT 250 WORDS)
Hypertension 1987 Nov
PMID:Selective modification of renal alpha 2-adrenergic receptors in Milan hypertensive rat strain. 282 76


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