Secretion of inhibin during the estrous cycle in the female Asian elephant (Elephas maximus)

Saroch Kaewmanee, Gen Watanabe, Miori Kishimoto, Wan Zhu Jin, Yuki Yamamoto, Tatsuya Yamamoto, Kentaro Nagaoka, Etsuo Narushima, Teruyuki Komiya, Kazuyoshi Taya

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


To define the source of circulating inhibin in female Asian elephants, the immunolocalizations of the inhibin α, βA and βB subunits, 3β-hydroxysteroid dehydrogenase (3β-HSD), aromatase cytochrome P450 (P450arom) and cytochrome 17α-hydroxylase P450 (P450 c17) were investigated. Concentrations of immunoreactive (ir-) inhibin, progesterone and follicle-stimulating hormone (FSH) during the estrous cycle were measured by radioimmunoassay. Inhibin immunoreactivity in follicular fluid and homogenate of corpora lutea was also measured. Immunolocalizations of inhibin subunits, 3β-HSD, P450arom and P450c17 were detected in the granulosa cells of antral follicles and luteal cells. The follicular fluid contained high levels of ir-inhibin and bioactive inhibin. The homogenate of corpora lutea also contained ir-inhibin. Serum ir-inhibin remained at low levels during the early non-luteal phase, began to increase from the late non-luteal phase and continued to increase during the early luteal phase. Serum ir-inhibin showed maximal levels in the middle of the luteal phase and gradually decreased to baseline three weeks prior to progesterone decline. The serum ir-inhibin levels were positively correlated with progesterone throughout the estrous cycle. On the other hand, ir-inhibin was negatively correlated with FSH during the late non-luteal and early luteal phases. These findings strongly suggest that the corpus luteum is one of the sources of inhibin as well as granulosa cells in the Asian elephant.

Original languageEnglish
Pages (from-to)77-82
Number of pages6
JournalJournal of Veterinary Medical Science
Issue number1
Publication statusPublished - Jan 2011
Externally publishedYes


  • Asian elephant
  • Corpora lutea
  • Follicles
  • Inhibin
  • Progesterone

ASJC Scopus subject areas

  • General Veterinary


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