11β-Hydroxysteroid Dehydrogenase Complementary Deoxyribonucleic Acid in Rainbow Trout: Cloning, Sites of Expression, and Seasonal Changes in Gonads

Abstract

11beta-Hydroxysteroid dehydrogenases (11beta-HSDs) are important steroidogenic enzymes for catalyzing the interconversion of active glucocorticoid (cortisol and corticosterone) and inert 11-keto forms (cortisone and 11-dehydrocorticosterone) in mammals. In teleosts, 11beta-HSD also plays a role in the production of the predominant androgen, 11-ketotestosterone, in male fish. In this study we cloned cDNAs encoding rainbow trout 11beta-HSD (rt11beta-HSD) from testes and head kidney. The predicted amino acid sequence, hydrophobicity analysis, and transient transfection assays with rt11beta-HSD in HEK293 cells showed that rt11beta-HSD is a homolog of mammalian 11beta-HSD type 2. rt11beta-HSD transcripts are present in steroidogenic tissues and in a number of other tissues. Strong in situ hybridization signals for rt11beta-HSD transcripts were found in Leydig cells of testes, in thecal cells of the early vitellogenic ovarian follicles, and in thecal and granulosa cells of the midvitellogenic and postovulatory follicles. Weaker signals were also found in head kidney interrenal cells from juvenile rainbow trout. Seasonal changes in rt11beta-HSD transcripts in testes showed a pattern similar to that of stress-induced serum cortisol levels, but not to serum androgen levels. High levels of rt11beta-HSD transcripts were found in ovarian follicles from late vitellogenesis through ovulation. These results raise the possibility of a role for rt11beta-HSD in the protection of developing gonads from the inhibitory effects of stress-induced cortisol.

Changes in mRNAs encoding steroidogenic acute regulatory protein, steroidogenic enzymes and receptors for gonadotropins during spermatogenesis in rainbow trout testes

“…potential gonadal steroidogenic capacity of an individual animal), knowing the weight of sample tissue used for RNA extraction and the amount of total RNA extracted, we were able to estimate target transcript abundance within individual testes. We then normalized data to GSI, in order to account for gonad weight varying with fish body weight, as in the work of Kusakabe et al (2002aKusakabe et al ( , 2003.…”

“…Furthermore, the localization of Leydig cells in testis during spermatogenesis changes with the maturational stage (Kusakabe et al 2003). Therefore, in order to avoid biasing the number of Leydig cells in each sample, testes samples for RNA extraction were collected as 300 mg cross-sections taken from the widest point, approximately 3 cm from the anterior end.…”

“…Salmonids are excellent study animals to examine the changes in steroidogenic enzyme gene expression in relation to steroid hormone synthesis, since germ cell development progresses in a synchronous fashion and dynamic changes in steroid hormone secretion occur during gametogenesis. In rainbow trout, cDNAs for most of the steroidogenic enzymes responsible for the synthesis of sex steroids have already been isolated: cytochrome P450 cholesterol side-chain cleavage (P450scc) (Takahashi et al 1993), cytochrome P450 17 -hydroxylase/17,20-lyase (P450C17) (Sakai et al 1992), 3 -hydroxysteroid dehydrogenase/n5-4-isomerase (3 -HSD) (Sakai et al 1994), cytochrome P450 aromatase (P450 arom) , cytochrome P450 11 -hydroxylase (P45011 ) (Liu et al 2000, Kusakabe et al 2002a, 11 -hydroxysteroid dehydrogenase (11 -HSD) (Kusakabe et al 2003) and 20 -hydroxysteroid dehydrogenase (20 -HSD) (Guan et al 1999). Recent studies reported changes in mRNA levels for key ovarian steroidogenic enzymes during a reproductive cycle in channel catfish (Kumar et al 2000), Arctic char (von Hofsten et al 2002) and rainbow trout (Nakamura et al 2005), and a few recent studies in male teleosts reported seasonal changes in transcript levels of a single steroidogenic enzyme (Liu et al 2000, Kusakabe et al 2002a.…”

Expression of 11β-hydroxysteroid-dehydrogenase 2 in Sertoli cells of boar testes

“…More recently 11ß-HSD2 was demonstrated to occur in the smooth endoplasmatic reticulum of rat Leydig cells (Ge et al, 2005b). In the rat, it is assumed that a peripubertal change of reductive activity (11ß-HSD1) in immature animals to oxidative activity (11ß-HSD2-like) in mature animals abolishes the inhibitory effect of cortisol on testosterone production and thus allows the pubertal rise of testosterone concentration in peripheral plasma (Welsh et al, 1982;Monder, 1990;Ge et al, 1997;Kusakabe et al, 2003).…”

11β-Hydroxysteroid dehydrogenase-type 2 evolved from an ancestral 17β-Hydroxysteroid dehydrogenase-type 2

“…These activities would appear to be converting cortisone to cortisol and 11-KT to 11 -OH-T [ Figure 1]. Cortisol is both a glucocorticoid and mineralocorticoid in fish, while 11-KT is the physiological androgen in fish [36][37][38][39][40]. This suggests that 11 -HSD3 has an important role in fish endocrine physiology.…”