Expression and Localization of Two Gonadotropin Receptors in Gonads of the Yellowtail Clownfish, Amphiprion Clarkii

Abstract

Two gonadotropins (GtH), FSH and LH, play central roles in vertebrate reproduction. They act through specific gonadotropin receptors (GtHr), Fshr and Lhr, respectively, to stimulate testicular and ovarian functions. To investigate the action of GtH in clownfish, we examined gonadal FSHR and LHR mRNA expression levels. Levels of LHr mRNA were similar in the ambisexual gonad of the male and the ovary of the female. In contrast, Fshr expression was higher in the male than in the female. Additionally, in situ hybridization identified the cellular location of the receptor transcripts. In the ambisexual gonads of the male, both receptor gene transcripts were evident in active testicular tissue, and they were not evident in non-active ovarian tissue. These findings support the hypothesis that clownfish modulate the activity of and response to GtHs by controlling the expression of the GtH receptors.