Specificity of Sertoli cells in isopods: The case of Saduria entomon L.

Authors:

• Elżbieta Gabała

Abstract

In Saduria entomon, as in other isopods, the male reproductive system is paired. The testes assume the form of three tubes opening independently into a vas deferens. The testis wall is built of Sertoli cells whose numerous long protrusions run in the lumen of the testis tubes. The Sertoli cells have large, polymorphic nuclei with distinct nucleoli. They also have a very well developed rough endoplasmic reticulum in the form of tubules as well as extensive Golgi complexes. In the cytoplasm of the Sertoli cells numerous lysosomes and secretory granules are observed. In isopods, as in other animals, protrusions of the Sertoli cells form compartments in which germ cells mature. In Saduria entomon, the ultrastructure of the Sertoli cells indicates their function specific to isopods. They are the site of macrotubule synthesis. The macrotubules are released by exocytosis to the compartments with maturing spermatozoa. In isopods mature spermatozoa of a specific structure are organised in bundles sometimes called spermatophores. There are very numerous macrotubules in the bundles, probably keeping spermatozoa arranged in the characteristic way typical of isopods. The Sertoli cells also produce material of medium electron density which, like macrotubules, are released to the testis compartments. Similar material fills the spaces between spermatozoa and macrotubules in the bundles.