title: Biochemical characterization and autoradiographic localization of [3H]PGE2 binding sites in rat kidney.
abstract: Specific binding sites for prostaglandin E2 (PGE2) in membranes obtained from whole kidney and from different areas of rat renal tissue were identified and quantified by in-vitro radioligand binding and localized by autoradiography. Analysis of the [3H]PGE2 binding by Scatchard plots revealed a single class of high-affinity binding sites in the whole kidney (KD = 5.1 +/- 0.4 nM; Bmax = 75 +/- 9 fmol mg-1 protein), the cortex (KD = 6.1 +/- 0.5 nM; Bmax = 58 +/- 5 fmol mg-1 protein) and the outer medulla (KD = 3.3 +/- 0.3 nM; Bmax = 376 +/- 59 fmol mg-1 protein). No reproducible Scatchard plots could be obtained in the inner medulla. PGE1 was equipotent with PGE2 in inhibiting [3H]PGE2 binding, whereas PGA2, PGB2, PGF2 alpha and PGI2 were 10- to 1000-fold less potent. Autoradiographs revealed sparse or no binding in glomeruli, proximal tubules or blood vessels. The pattern of distribution of [3H]PGE2 binding was consistent with the anatomical localization of the distal tubule and in particular the thick ascending limbs of Henle. Based on the distribution and cellular localization of the [3H]PGE2 binding sites, our data support the hypothesis that the physiological role of PGE2 receptors is coupled to the regulation of sodium transport across segments of the distal tubule.
authors.affiliation: Department of Clinical Pharmacology, University Hospital of Lund, Sweden.
authors.forename: L O
authors.initials: LO
authors.lastname: Eriksson
authors.forename: B
authors.initials: B
authors.lastname: Larsson
authors.forename: K E
authors.initials: KE
authors.lastname: Andersson
mesh_terms: D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D015232:Dinoprostone / Q000493:pharmacokinetics; D066298:In Vitro Techniques; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D007672:Kidney Cortex / Q000166:cytology / Q000378:metabolism; D007679:Kidney Medulla / Q000166:cytology / Q000378:metabolism; D008297:Male; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D011982:Receptors, Prostaglandin / Q000032:analysis*; D018078:Receptors, Prostaglandin E
chemical_list: D011982:Receptors, Prostaglandin; D018078:Receptors, Prostaglandin E; D015232:Dinoprostone