Fish 3β-Hydroxysteroid Dehydrogenase/Δ5-Δ4Isomerase: Antibody Production and Their Use for the Immunohistochemical Detection of Fish Steroidogenic Tissues

Abstract We have produced polyclonal antibodies against two oligopeptides corresponding to middle and c-terminal regions of amino acid sequences predicted from rainbow trout (Oncorhynchus mykiss) 3β-hydroxysteroid dehydrogenase (3β-HSD) cDNA (Sakai et al., 1994, FEBS Letters 350, 309-313). Both antibodies (α-tr3β-M and α-tr3β-C) recognized recombinant rainbow trout 3β-HSD protein derived from rabbit reticulocyte lysate system and non-steroidogenic mammalian COS-1 cell lysate. Immunoblot analysis of rainbow trout ovarian follicle homogenates revealed specific recognition of 3β-HSD protein, in rainbow trout testis, furthermore, immunoreactive 3β-HSD localized in Leydig cells in the interstitium of immature testes and interrenal cells in the head kidney. These results indicate that both α-3β-HSD antibodies recognized rainbow trout 3β-HSD protein at the level of immunoblot and immunohistochemical analyses. Furthermore, both antibodies also recognized immunohistochemically 3β-HSD in various steroidogenic organ...