Localization of mRNAs encoding Ca2+-inhibitable adenylyl cyclases along the renal tubule. Functional consequences for regulation of the cAMP content.
Expression of Ca2+-inhibitable types V and VI adenylyl cyclases was studied by reverse transcription-polymerase chain reaction in rat renal glomeruli and nephron segments isolated by microdissection. Quantitation of each mRNA was achieved using a mutant cRNA which differed from the wild type by substituting two bases to create a new restriction site in the corresponding cDNA. Type VI mRNA was present all along the nephron but was more abundant in distal than in proximal segments. The expression of type V mRNA was restricted to the glomerulus and to the initial portions of the collecting duct. Expression of the Ca2+-insensitive type IV mRNA studied on the same samples was evidenced only in the glomerulus. The functional relevance of the expression of Ca2+-inhibitable isoforms was studied by measuring cAMP content in the microdissected outer medullary collecting duct which expressed both type V mRNA (2367 +/- 178 molecules/mm tubular length; n = 8) and type VI mRNA (5658 +/- 543 molecules/mm, n = 8). Agents known to increase intracellular Ca2+ in this segment induced a Ca2+-dependent inhibition on either arginine vasopressin- or glucagon-stimulated cAMP level. The characteristics of these inhibitions suggest a functional and differential expression of types V and VI adenylyl cyclases in two different cell types of the rat outer medullary collecting duct.
Chabardès
D
D
Département de Biologie Cellulaire et Moléculaire, CEA Saclay 91191 Gif sur Yvette Cedex, France.
Firsov
D
D
Aarab
L
L
Clabecq
A
A
Bellanger
A C
AC
Siaume-Perez
S
S
Elalouf
J M
JM
D000067956:Adenylyl Cyclase Inhibitors; D000262:Adenylyl Cyclases / Q000235:genetics*; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D001483:Base Sequence; D002118:Calcium / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism*; D017931:DNA Primers; D005934:Glucagon / Q000494:pharmacology; D007679:Kidney Medulla / Q000187:drug effects / Q000378:metabolism; D007685:Kidney Tubules, Collecting / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
D000067956:Adenylyl Cyclase Inhibitors; D017931:DNA Primers; D012333:RNA, Messenger; D001127:Arginine Vasopressin; D005934:Glucagon; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D002118:Calcium