Molecular analysis of vasopressin receptors in the rat nephron. Evidence for alternative splicing of the V2 receptor.

摘要: Expression and regulation of vasopressin V2 V1a receptors were studied at the mRNA level in rat kidney. Two variants identified shown to arise from a single gene by alternative splicing using one donor two different acceptor sites. The long (V2L) form encodes adenylyl cyclase-coupled receptor. short (V2S) lacks nucleotide sequence encoding putative seventh transmembrane domain undergoes frame shift its 3'end coding region; it is inactive on cyclase pathway transfected cells. Measurement mRNAs, carried out quantitative reverse transcription-polymerase chain reaction (RT-PCR) microdissected nephrons, demonstrated that neither V2L, V2S nor V1A mRNAs are expressed glomeruli proximal tubules (<100 copies/glomerulus or mm tubular length), whereas they present ascending limb Henle's loop collecting tubule. V2L mRNA, which always predominant these structures, throughout tubule 10 times higher levels (30,000 copies/mm) than thin thick limbs. ratio over constant (15%) all nephron segments; hence high only observed slightly limb, absent reaches maximum cortical duct (4,000 copies/mm), before gradually decreasing undetectable terminal duct. Finally, vivo administration agonist decreased 50% but did not alter level. We conclude this study provides quantitation, molar basis, receptor kidney demonstrates occurence spliced similarly down-regulated.