Gonadal structure and P450scc and 3?-HSD immunoreactivity in the gobiid fish Trimma okinawae during bidirectional sex change

Abstract

The process of sex change in the gobiid fish Trimma okinawae was investigated by gonad histology and immunohistochemistry of two steroidogenic enzymes, P450 cholesterol-side-chaincleavage (P450scc) and 3 -hydroxysteroid dehydrogenase (3 -HSD). Irrespective of sexual phase, gonads comprised both ovarian and testicular tissues. Females changed sex to male within 7 days, reverting again to female over an 11-day period. In each sexual phase of the females, the 2nd (2DF-M) and 4th (4DF-M) day after the initiation of sex change to male, the males, and 2nd (2DM-F), 4th (4DM-F), and 6th (6DM-F) days after the initiation of reversion from male to female, histological observations were made. In the ovary during the female, 2DF-M, 4DF-M, and 6DM-F phases, both vitellogenic and previtellogenic oocytes were present, but only previtellogenic oocytes were found in the other phases. The testis contained sperm in all phases, but sperm ducts were not visible in the female phase. In the ovary, P450scc immunoreactivity of interstitial cells was strongly or moderately detected, although weak in the male phase. In contrast, P450scc immunoreactivity in thecal cells was found in all but the male and 2DM-F phases. 3 -HSD immunoreactive interstitial cells were detected in all phases, but only weakly so in the male and 2DM-F phases. 3 -HSD immunoreactive thecal cells were observed in all stages without the male and 2DM-F and 4DM-F phases. In the testis, moderate P450scc and 3 -HSD immunoreactivity was regularly found in the Leydig cells in all the phases. These results suggest that functional steroids including testosterone are produced in any sexual phases.

Immunolocalization of steroidogenic enzymes in gonads of European eel,Anguilla anguilla(L.)

“…Contrary to that observed in other teleosts (Kobayashi et al., 1998; Sunobe et al., 2005a,b; Ijiri et al., 2006), in A. anguilla some Sertoli cells were positive to P450scc and 3β‐HSD in testes of silver eels containing meiotic cells. Using histochemical techniques applied to cryostatic sections, steroidogenic activity was detected in the intratubular cells, homologues to the Sertoli cells in Tilapia mossambica (Yaron, 1966), in the common mummichog Fundulus heteroclitus (Bara, 1969), and in Salmo gairdneri (Van den Hurk et al., 1978).…”

“…The immunolocalization of P450scc, 17 α‐hydroxylase/C17,20 lyase (P450c17), 3β‐HSD and P450arom was studied during spermatogenesis in O. mykiss (Kobayashi et al., 1998) and during artificially induced sex reversal in O. niloticus (Chang et al., 1997; Nakamura et al., 2003; Bhandari et al., 2006). The immunolocalization of P450scc, P450c17 and P450arom was also studied in testes and ovaries of the Japanese eel Anguilla japonica during gonad development (Ijiri et al., 2003, 2006), and in the gobiid fish Trimma okinawae during reversal of both sexes (Sunobe et al., 2005a,b).…”

Gregariousness and protandry promote reproductive insurance in the invasive gastropod Crepidula fornicata: evidence from assignment of larval paternity

“…That some fathers are brooding females at time of collection demonstrates that an individual can effectively reproduce as both a male and a female over a relatively short time interval and contribute as both father and mother to larvae of a given cohort. Sexual transformation lasts 61 days (Coe 1938); a much longer time than in many protogynous fish species (Reavis & Grober 1999; Sunobe et al . 2005) but similar to other protandrous species of calyptraeids (Warner et al .…”

Bending Genders: The Biology of Natural Sex Change in Fish

“…2 C), with either portion being reproductively fully functional and so characterising the current sexual phenotype Cole, 2010Cole, , 2011Kuwamura et al, 2015]. Maintaining a bisexual gonad affords these species the flexibility to rapidly adjust their sexual phenotype (e.g., 7 days in T. okinawae , Sunobe et al [2005]) and exploit any reproductive opportunity, consecutively if necessary. Sequential hermaphroditism has multiple evolutionary origins in gobiid fishes, and there is substantial taxon-specific variation in gonadal configuration.…”