Adrenergic signal transduction in the kidney.
During signal transduction, renal adrenoceptors associate with (as in other tissues) specific members of a family of GTP-binding (G) proteins. Renal beta-adrenoceptors activate adenylate cyclase in glomeruli and distal nephrons via an interaction with the stimulatory G protein Gs. alpha 1-Adrenoceptors bind to an as yet uncharacterized G protein and activate phospholipase C to produce the putative second messengers 1,4,5-inositol trisphosphate and diacylglycerol. alpha 1-Adrenoceptors are found in most segments of the nephron where they regulate sodium reabsorption, and metabolic functions such as gluconeogenesis. Renal alpha 2-adrenoceptors which inhibit adenylate cyclase through the inhibitory G protein Gi are located mainly in the proximal convoluted tubule and the collecting ducts. Another population of alpha 2-adrenoceptors has been identified which enhances the sodium-hydrogen exchange across the luminal membrane of proximal tubules. Ongoing research is clarifying the locations and functions of these renal adrenoceptor subtypes.
Jeffries
W B
WB
University of Texas Southwestern Medical Center, Department of Pharmacology, Dallas.
Pettinger
W A
WA
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002352:Carrier Proteins / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D011941:Receptors, Adrenergic / Q000378:metabolism*; D015398:Signal Transduction; D017923:Sodium-Hydrogen Exchangers; D014018:Tissue Distribution; D010738:Type C Phospholipases / Q000378:metabolism
D002352:Carrier Proteins; D011941:Receptors, Adrenergic; D017923:Sodium-Hydrogen Exchangers; D010738:Type C Phospholipases; D000262:Adenylyl Cyclases