Abstract 1940 Poster Session II, Sunday, 5/2 (poster 184)
Adenylyl cyclases (AC) are known to consist of a family of enzymes that catalyze the formation of the second messenger cAMP. At least nine isoforms have been cloned so far, which exhibit unique patterns of tissue distribution and basal activities. Distinct adenylyl cyclase isoforms differ in their capacity to be stimulated or inhibited by G protein αi, αs and β/γ subunits, protein kinase C and intracellular calcium. The distribution of adenylyl cyclases in the kidney is only partially known even though they play important roles in the signal transduction in the nephron. Many receptors are known to couple to adenylyl cyclases, but little is known about their linkage to specific adenylyl cyclase isoforms. We conducted a reverse transcription-polymerase chain reaction (RT-PCR) study to investigate the tissue distribution of adenylyl cyclase isoforms in the nephron of Wistar Kyoto rats (WKY). RNA was extracted from freshly microdissected nephron segments (glomerulus, proximal tubule, thin limb of Henle, thick ascending limb of Henle, distal tubule, cortical collecting duct, outer medullary collecting duct and inner medullary collecting duct) as well as from WKY immortalized proximal tubule cells. Using PCR primers specific for adenylyl cyclases II-IX, mRNA encoding adenylyl cyclases II-IX were identified in tissues from both sources. Western blots and immunohistochemistry studies confirmed our results. Adenylyl cyclase isoform III for instance was found in the glomerulus, proximal tubule, thin limb of Henle and inner medullary collecting duct whereas adenylyl cyclase isoforms VI and VIII were found along the whole nephron. The individual adenylyl cyclase isoforms showed unique differential tissue expressions suggesting an important role in the regulation of signal transduction within different nephron segments.
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Bek, M., Asico, L., Yamaguchi, I. et al. Differential Expression of Adenylyl Cyclases in the Rat Nephron. Pediatr Res 45, 329 (1999). https://doi.org/10.1203/00006450-199904020-01956