Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.5 (5'-nucleotidase)
 3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mesangial cells possess a variety of receptors for hormones and autacoids. They are also equipped with ectoenzymes whose function may be to control the availability of autacoids and hormones at their receptor sites. Several examples are considered. Receptors for angiotensin II (AII) are present both on murine and human mesangial cells. One single group of receptors has been demonstrated in each of these preparations. Mesangial cell AII receptors are linked to phospholipase C via a G protein. They belong to the AT1 subtype because (125I)AII is displaced from its binding sites preferentially by AT1 antagonists such as DUP 753 and EXP 3,174, whereas AT2 antagonists are much less potent. AT1 antagonists suppress the biological effects of AII in mesangial cells, including the stimulation of intracellular calcium concentration and the increase of prostaglandin synthesis and of (3H)leucine incorporation. Mesangial cells also have receptors for atrial natriuretic factor, but the distribution between B receptors with guanylate cyclase activity and clearance (C) receptors varies with the species. Both types are present in murine mesangial cells, whereas only C receptors are found in human mesangial cells. In contrast, human epithelial cells possess both B and C receptors. Ecto-5'-nucleotidase activity results in the production of adenosine, which acts on mesangial cells through A1 and A2 receptors. This enzyme is markedly induced in rat mesangial cells by interleukin-1, whose effect is mediated in part by prostaglandin E2 and cAMP. Various other cAMP-stimulating agents also induce 5'-nucleotidase expression in rat mesangial cells. Ectopeptidases are present in all glomerular cell types but essentially in epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cell surface receptors and ectoenzymes in mesangial cells. 131 10

Regulation of coronary blood flow (CBF) is a complex process in which many neural, mechanical, myogenic and metabolic factors are involved and is largely controlled by local factors. Our recent results suggest that CBF and oxygen delivery to cardiac tissue is regulated according to the actual needs of the tissue, determined by oxygen consumption in the mitochondrial respiratory chain, controlled by the energy state of the cell. Several substances have been proposed to serve as messengers between the cardiac myocyte and the vascular smooth muscle cells. Abundant evidence has been accumulated showing that adenosine is an important regulator of CBF, its effects being thought to be mediated by binding to specific external or internal surface receptors, with regulatory link to adenylate cyclase. There is also evidence that adenosine formation takes place intracellularly, predominantly via a cytosolic 5'-nucleotidase. The intracellular level of adenosine is thought to be under delicate control by adenosine producing and metabolizing enzymes. Several arachidonic acid metabolites, especially prostacyclin, are also involved in the regulation of coronary circulation. The physiological significance of atrial natriuretic factor, which also seems to regulate CBF, cannot be established at this stage.
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PMID:Regulation of coronary blood flow. 295 5