PUBLICATION

Thyroid Hormone Stimulates the Proliferation of Sertoli Cells and Single Type A Spermatogonia in Adult Zebrafish (Danio rerio) Testis

Authors
Morais, R.D., Nóbrega, R.H., Gómez-González, N.E., Schmidt, R., Bogerd, J., França, L.R., and Schulz, R.W.
ID
ZDB-PUB-130905-30
Date
2013
Source
Endocrinology   154(11): 4365-76 (Journal)
Registered Authors
Bogerd, Jan, Schulz, Rüdiger W.
Keywords
none
MeSH Terms
  • Animals
  • Cell Proliferation/drug effects*
  • Gene Expression Regulation/drug effects
  • Gene Expression Regulation/physiology
  • Male
  • RNA, Messenger/genetics
  • RNA, Messenger/metabolism
  • Receptors, Thyroid Hormone/genetics
  • Receptors, Thyroid Hormone/metabolism
  • Sertoli Cells/cytology*
  • Sertoli Cells/drug effects*
  • Sertoli Cells/physiology
  • Spermatogonia/cytology*
  • Spermatogonia/drug effects*
  • Thyroid Hormones/pharmacology*
  • Triiodothyronine/pharmacology
  • Zebrafish/physiology*
PubMed
24002037 Full text @ Endocrinology
Abstract

Thyroid hormones participate in regulating growth and homeostatic processes in vertebrates, including development and adult functioning of the reproductive system. Here we report a new stimulatory role of thyroid hormone on the proliferation of Sertoli cells (SCs) and single, type A undifferentiated spermatogonia (Aund) in adult zebrafish testes. A role for T3 in zebrafish testis is suggested by in situ hybridization studies, which localized thyroid receptor α (thrα) in SCs and the β (thrβ) mRNA in Sertoli and Leydig cells. Using a primary zebrafish testis tissue culture system, the effect of T3 on steroid release, spermatogenesis, and the expression of selected genes was evaluated. Basal steroid release and Leydig cell gene expression did not change in response to T3. However, in the presence of FSH, T3 potentiated gonadotropin-stimulated androgen release as well as androgen receptor (ar) and 17α-hydroxylase/17,20 lyase (cyp17a1) gene expression. Moreover, T3 alone stimulated the proliferation of both SCs and Aund, potentially resulting in newly formed spermatogonial cysts. Additional tissue culture studies demonstrated that Igf3, a new, gonad-specific member of the IGF family, mediated the stimulatory effect of T3 on the proliferation of Aund and SCs. Finally, T3 induced changes in connexin 43 mRNA levels in the testis, a known T3-responsive gene. Taken together, our studies suggest that T3 expands the population of SCs and Aund involving Igf signaling and potentiates gonadotropin-stimulated testicular androgen production as well as androgen sensitivity.

Genes / Markers
Figures
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Antibodies
Orthology
Engineered Foreign Genes
Mapping