title: The intrarenal distribution of tritiated para-aminohippuric acid determined by a modified technique of section freeze-dry radioautography.
abstract: Section freeze-dry radioautography has been used to examine the intrarenal distribution of a water-soluble organic acid (para-aminohippuric acid (PAH-3H)) under constant-infusion, steady-state conditions in mouse and rat kidney in vivo. The technique described here has the following advantages: (a) Sectioning and freeze-drying are accomplished in a closed cryostat at temperatures below -40 degrees C; (b) Handling of the section is facilitated by mounting of the section-to-be on adhesive-coated Saran Wrap prior to cutting; (c) Unembedded freeze-dried sections are attached to photographic film at ambient temperature in the dark room; (d) Fixation follows completion of radioautographic exposure and precedes photographic development; (e) Permanent close contact is maintained between tissue and film. Morphologic preservation compared favorably with that obtained by optimal fixation techniques, which, however, permit diffusion. Cellular accumulation of PAH-3H during secretion was demonstrated in the proximal tubule under steady-state conditions in vivo. The cellular concentration of PAH-3H was uniform throughout the length of the proximal tubule in mouse and rat kidney.
mesh_terms: D000618:Aminohippuric Acids / Q000032:analysis*; D000818:Animals; D001345:Autoradiography; D002467:Cell Nucleus; D005260:Female; D005612:Freeze Drying; D006651:Histocytochemistry; D002479:Inclusion Bodies; D007684:Kidney Tubules / Q000032:analysis / Q000166:cytology*; D008722:Methods; D008853:Microscopy; D008858:Microscopy, Phase-Contrast; D008867:Microtomy; D008928:Mitochondria; D010969:Plastics; D051381:Rats; D014316:Tritium
chemical_list: D000618:Aminohippuric Acids; D010969:Plastics; D014316:Tritium