The Fine Structure of Podocytes in Crayfish Antennal Glands

The podocytes in the coelomosac of the crayfish Procambarus clarkii were examined using electron microscopy and by focusing on the growth stage. In immature animals, the cells of the coelomosac are likened to the vertebrate podocyte in that it has a flattened shape and small vacuoles as well as pinocytotic vesicles. Podocytes in mature crayfish have various sizes of vesicles in the cytoplasm, and they have elongated shapes. Our SEM observations show “blebs” as sections of the long elongated head of a podocyte, which push each other in the urinary space. Podocytes have long projections which are connected to each other via slit membranes. Wide space is required for podocytes, and they may secure the space needed to absorb the necessary materials that pass through the slit membrane and basal lamina. The morphological differences between the podocytes of mature and immature crayfish may reflect the amounts of metabolic waste. This reinforces the suggestion that in decapoda, podocytes have a very active function in the secretion and reabsorption of large molecules.