A Histological Study on the Nephrons in Rutilus frisii kutum of Caspian Sea

Rutilus frisii kutum is a cyprinid fish, distributing along the Caspian Sea, from Atrak River (Turkmenistan) to Kura River (Azerbaijan). This fish is one of the commercially important fishes in the south of the Caspian Sea. This species is normally a medium-sized fish, typically reaching 45-70 cm in length, weighing up to 5 kg. The kidney of the vertebrate is the main organ which balances the body fluid homeostasis. A histological study was carried out on the nephron of Rutilus frisii kutum for the first time. A total number of ten adult fish from the southern Caspian Sea fishing region were subjected to this investigation. The kidneys were removed and immediately fixed in 10% buffered formalin for 24 hours. Then, they were transferred into the tissue processor. Paraffin blocks were made and thin sections of five microns were cut. The sections were subjected to staining by Haematoxylin & Eosin. They were studied under the light microscope and photomicrographs were taken. The different parts of nephron were renal corpuscles, two types of proximal convoluted tubules, an intermediate segment and collecting ducts. There were no evidence for distal convoluted tubules and henle loops.