title: The ultrastructure of lobule boundary cells and Leydig cell homologs in the testis in a cichlid fish, Cichlasoma nigrofasciatum.
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D004721:Endoplasmic Reticulum; D005399:Fishes / Q000033:anatomy & histology*; D002479:Inclusion Bodies; D007985:Leydig Cells / Q000166:cytology*; D008297:Male; D008854:Microscopy, Electron; D012708:Sertoli Cells / Q000378:metabolism; D013094:Spermatozoa; D013256:Steroids / Q000096:biosynthesis; D013737:Testis / Q000166:cytology*
chemical_list: D013256:Steroids