Differentiation of steroid-producing cells during ovarian differentiation in the protogynous malabar grouper, epinephelus malabaricus

Ryosuke Murata, Hirofumi Karimata, Yasuhisa Kobayashi, Ryo Horiguchi, Kazuo Kishimoto, Motofumi Kimura, Tohru Kobayashi, Kiyoshi Soyano, Masaru Nakamura

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


To understand the mechanism of sex differentiation in the protogynous Malabar grouper Epinephelus malabaricus, we performed an immunohistochemical investigation of the expression of three steroidogenic enzymes, cholesterol-side-chain-cleavage enzyme (CYP11a), aromatase (CYP19a1a), and cytochrome P45011beta-hydroxylase (CYP11b), in the gonads during ovarian differentiation. Strong positive immunoreactivity against CYP11a, the key enzyme of steroidogenesis, and CYP19a1a which is essential for estrogen (17beta-estradiol) production, appeared first in the somatic cells surrounding gonial germ cells in undifferentiated gonads and throughout ovarian differentiation. However, positive immunoreactivity against CYP11b, which is important for androgen (11-ketotestosterone) production, first appeared in the cluster of somatic cells in the ovary tunica near the dorsal blood vessel after differentiation. CYP19a1a and CYP11b did not co-localize in any cells. These results indicate that there are two types of steroid-producing cells, estrogen-producing cells and androgen-producing cells, in the gonads of this fish, and they are distributed differently, suggesting that these cells are derived from different somatic cells. Estrogen-producing cells appeared prior to ovarian differentiation, while androgen-producing cells were first detected after ovarian differentiation. These results suggest that endogenous estrogen is involved in ovarian differentiation.

Original languageEnglish
Pages (from-to)619-625
Number of pages7
JournalInternational Journal of Developmental Biology
Issue number6
Publication statusPublished - 2011


  • 11-ketotestosterone
  • 17beta-estradiol
  • Grouper
  • Protogynous hermaphrodite
  • Steroid-producing cell

ASJC Scopus subject areas

  • Embryology
  • Developmental Biology


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