Isolation and characterization of the cDNA encoding the tilapia (Oreochromis niloticus) cytochrome P450 aromatase (P450arom): changes in P450arom mRNA, protein and enzyme activity in ovarian follicles during oogenesis

Chang, X T; Kobayashi, Toru; Kajiura, Hiroko; Nakamura, Masaru; Nagahama, Yoshitaka

doi:10.1677/jme.0.0180057

Cited by 128 publications

(54 citation statements)

References 14 publications

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“…Although we were unable to measure P450 aromatase activity, several previous studies with teleosts including zebrafish have shown that mRNA levels of cyp19 are correlated well with aromatase activity (Fukada et al, 1996;Chang et al, 1997;Hinfray et al, 2006). In this aspect, several previous reports have also shown that the inhibition of the aromatase cyp19 gene can reduce estradiol production, leading to an increase in the ratio of androgens to estrogens, and finally affecting the sex ratio (Guiguen et al, 2010;Shang et al, 2006).…”

Section: Discussionmentioning

confidence: 73%

The progestin levonorgestrel affects sex differentiation in zebrafish at environmentally relevant concentrations

et al. 2015

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Section: Discussionmentioning

confidence: 73%

The progestin levonorgestrel affects sex differentiation in zebrafish at environmentally relevant concentrations

et al. 2015

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“…The most abundant transcripts for P450aromA could be seen in the granulosa cells of mid-and late-vitellogenesis and weak signals were seen in thecal cells throughout vitellogenesis. Aromatase activity was reported to be present in ovarian follicles of several teleosts including Nile tilapia (Chang et al, 1997), amago salmon (Young et al, 1983) and medaka (Fukada et al, 1996). However, these studies did not examine which type of aromatase is localized in ovarian follicles.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Two Types of Cytochrome P450 Aromatase in the Serial-sex Changing Gobiid Fish, Trimma okinawae

Kobayashi

Nakamura

et al. 2004

Zoological Science

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-To investigate the role of estrogen in the serial-sex changing fish Trimma okinawae , we isolated complementary DNAs encoding two distinct cytochrome P450 aromatase isoforms from adult ovary and brain (termed P450aromA and P450aromB, respectively). Sequence and phylogenic analyses showed that the goby P450arom forms belong to two separate CYP19 subfamilies. Transient expression of these cDNAs in HEK293 cells caused conversion of exogenous testosterone to estradiol-17 b . RT-PCR showed that P450aromA was expressed in the brain, spleen, testis and ovary. P450aromB was expressed in the brain, liver, testis and ovary. In situ hybridization studies showed that P450aromA mRNA, but not P 450aromB mRNA, was present in both ovary and testis. Positive signals were restricted to granulosa cells of vitellogenic follicles and interstitial cells of mature testis. Ovarian expression of both P450arom genes during the spawning cycle was examined by quantitative real-time RT-PCR. P450aromA transcripts increased during vitellogenesis and decreased prior to spawning. In contrast, P450aromB transcripts were barely detectable and did not correlate with ovarian development. These findings suggest that P450aromA, but not P450aromB, is involved in regulating ovarian vitellogenesis in goby.

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“…In fish, two aromatase isoforms have been described, one preferentially expressed in the ovary (coded by the CYP19a gene) and one preferentially expressed in the brain (coded by the CYP19b gene) (e.g. Chang et al, 1997;Tchoudakova and Callard, 1998). In the gonads, aromatase has been shown to be a key enzyme regulating sexual differentiation in fish.…”

Section: Introductionmentioning

confidence: 99%

Brain and gonadal aromatase activity and steroid hormone levels in female and polymorphic males of the peacock blenny Salaria pavo

Gonçalves

Teles

Alpedrinha

et al. 2008

Hormones and Behavior

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In the peacock blenny Salaria pavo large males with well-developed secondary sexual characters establish nests and attract females while small "sneaker" males mimic female sexual displays in order to approach the nests of larger males and parasitically fertilize eggs. These alternative reproductive tactics are sequential, as sneakers irreversibly switch into nesting males. This transition involves major morphologic and behavioral changes and is likely to be mediated by hormones. This study focuses on the role of aromatase, an enzyme that catalyses the conversion of androgens into estrogens, in the regulation of male sexual polymorphism in S. pavo. For this, sex steroid plasma levels and aromatase activity (AA) in gonads, whole brain and brain macroareas were determined in sneakers, transitional males (i.e. sneakers undergoing the transition into nesting males), nesting males and females collected in the field. AA was much higher in ovarian tissue than in testicular tissue and accordingly circulating estradiol levels were highest in females. This supports the view that elevated AA and estradiol levels are associated with the development of a functional ovary. Transitional males are in a non-reproductive phase and had underdeveloped testes when compared with sneakers and nesting males. Testicular AA was approximately 10 times higher in transitional males when compared with sneakers and nesting males, suggesting high AA has a suppressive effect on testicular development. Nesting males had significantly higher plasma levels of both testosterone (T) and 11-ketotestosterone when compared with the other male morphs and previous studies demonstrated that these androgens suppress female-like displays in sneakers. In the brain, AA was highest in macroareas presumably containing hypothalamic nuclei traditionally associated with the regulation of reproductive behaviors. Overall, females presented the highest levels of brain AA. In male morphs AA increased from sneakers, to transitional males, to nesting males in all brain macroareas. These results suggest that the transition into the nesting male tactic is accompanied both by an increase in testicular androgen production and by a higher conversion of androgens into estrogens in the brain. The increase in androgen production is likely to mediate the development of male secondary sexual characters while the increase in brain AA may be related to the behavioral changes associated with tactic transition.

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Isolation and characterization of the cDNA encoding the tilapia (Oreochromis niloticus) cytochrome P450 aromatase (P450arom): changes in P450arom mRNA, protein and enzyme activity in ovarian follicles during oogenesis

Cited by 128 publications

References 14 publications

The progestin levonorgestrel affects sex differentiation in zebrafish at environmentally relevant concentrations

The progestin levonorgestrel affects sex differentiation in zebrafish at environmentally relevant concentrations

Characterization of Two Types of Cytochrome P450 Aromatase in the Serial-sex Changing Gobiid Fish, Trimma okinawae

Brain and gonadal aromatase activity and steroid hormone levels in female and polymorphic males of the peacock blenny Salaria pavo

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