| 11309 | Ultrastructural Studies on the Heart of Boltenia ovifera (Sea Potato) | | | | | | |
| 11460 | Ultrastructure of Extracellular Material of the Single Cell-Layered Heart of Boltenia ovifera | | | | | | |
| 10744 | Ultrastructure of Marine Calcification | | | | | | |
| 10578 | Ultraviolet Induced Cleavage Delay And Its Photorecovery In Echinarachnius parma | | | | | | |
| 10424 | Unarrested passage of lymphoma‑leukemia cells through liver and kidney | | | | | | |
| 10641 | Unilateral Furrowing in the Eggs of Hydractinia and Echinorachnius | | | | | | |
| 11957 | Unusual Bacterial Flora in Leach's Storm-Petrel, Leucorhoa oceanodroma | | | | | | |
| 12835 | Up-regulation of Mrp2 expression and transport activity by dexamethasone in killifish (Fundulus heteroclitus) renal proximal tubules | | | | | | |
| 10357 | Upon the Presence of More Than One Chromatophorotropic Substance in Both Sinus Glands and Commissural Ganglia | | | | | | |
| 12780 | Upregulation of Multidrug Resistance-Associated Protein (Mrp2) in Renal Proximal Tubules from Killifish, Fundulus heteroclitus | | | | | | |
| 12263 | Upregulaton of the Na-K-Cl Cotransporter Protein in Saltwater Adaptation of the Rainbow Trout, Salmo gairdneri | | | | | | |
| 10505 | Uptake and run-out of chlorphenol red by isolated renal tubules of Flounder in vitro | | | | | | |
| 10647 | Uptake of Thymidine and Cytidine by Eggs of the Sand dollar, Echinarachnius parma | | | | | | |
| 11783 | Uptake of trimethylamine-N-oxide (TMAO) and trimethylamine (TMA) in skeletal muscle and rectal gland of shark (Squalus acanthias) | | | | | | |
| 11650 | Urea & Water Transport in Isolated Perfused Renal Tubules of the Dogfish Shark, Squalus acanthias | | | | | | |
| 10532 | Urea and Ammonia Excretion in the Frog | | | | | | |
| 10524 | Urea and Thiourea Excretion by Dogfish Kidney and Gill: Effect of Temperature | | | | | | |
| 10919 | Urea Biosynthesis and Excretion in Freshwater and Marine Elasmobranch | | | | | | |
| 12410 | Urea Cycle Enzymes in the Rock Gunnel, Pholis gunnellus | | | | | | |
| 11576 | Urea Effluxes from the Squalus acanthias Pub: The Effect of Stress | | | | | | |
| 10485 | Urea excretion and diving in the Seal (Phoca vitulina L.) | | | | | | |
| 10423 | Urea excretion in Toads and Frogs | | | | | | |
| 10844 | Urea Metabolism and Osmoregulation in the Skate, Raja erinacea | | | | | | |
| 11358 | Urea Permeability in Pregnant Endometrium of Spiny dogfish (Squalus acanthias) | | | | | | |
| 10997 | Urea Reabsorption by the Skate Nephron: Micropuncture of Collecting Ducts in Raja erinacea | | | | | | |