Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dopamine has been proposed as an intrarenal natriuretic hormone. We reported previously that inner medullary collecting duct (IMCD) cells express a novel DA2-like dopamine receptor (namely, DA2K) that is linked to stimulation of prostaglandin E2 (PGE2) production. In this study we examined whether locally formed dopamine could stimulate PGE2 production in cultured IMCD cells. L-Dopa stimulated PGE2 production dose dependently in cultured IMCD cells (concentration for half-maximal stimulation, 54.3 microM; maximal stimulation, 212.7% of basal), with the maximal stimulation similar to that obtained with dopamine. This effect was blocked by aromatic L-amino acid decarboxylase (AADC) inhibitors and DA2-receptor antagonists. IMCD cells also had measurable AADC activity and produced dopamine from exogenously added L-dopa. AADC inhibitors and DA2 antagonists also lowered basal PGE2 levels, suggesting that dopamine was being formed constitutively in culture. These results suggest that cultured IMCD cells have the capacity to take up and convert L-dopa to dopamine, which then stimulates PGE2 production via DA2K receptors. These results further suggest that locally formed dopamine could act as an autocrine/paracrine hormone in the kidney inner medulla to regulate PGE2 synthesis and water and electrolyte excretion.
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PMID:Prostaglandin E2 production in rat IMCD cells. II. Possible role for locally formed dopamine. 168 39

The present work proposes an extra neural site of catecholamine production along the nephron. LLC-PK(1), MDCK, and mIMCD-3 (proximal and distal tubules and inner medullary collecting duct, respectively) presented the following amine concentrations in the cell homogenates: Norepinephrine = 275+/-34, 56+/-16 and 255+/-21; Epinephrine = 161+/-20, 83+/-17 and 53+/-7; and Dopamine = 63+/-15, 39+/-6 and 36+/-7 pg/mg cell protein (Means +/- SEM), respectively. The culture medium showed Norepinephrine = 168+/-25, 22+/-3 and 135+/-8; Epinephrine = 32+/-6, 152+/-17 and 39+/-5; and Dopamine = 27+/-9, 241+/-34 and 26+/-5 pg/mg cell protein, respectively. The synthesis enzymes as tyrosine hydroxylase, dopa decarboxylase and dopamine beta-hydroxylase were detected by Western blotting. Biopterin, the enzymatic cofactor of tyrosine hydroxylase, was quantified in the intracellular and medium of mIMCD-3 cells (17+/-4 and 24+/-3 nmol/mg cell protein, respectively) and in the medium of MDCK cells (19+/-4 nmol/mg cell protein). The data confirmed that the proximal tubule is an important source of dopa decarboxilase and Dopamine and epithelial cell along the nephron express the biochemical pathway for catecholamine production.
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PMID:Catecholamine production along the nephron. 1798 74