Journal
FRONTIERS IN ENDOCRINOLOGY
Volume 11, Issue -, Pages -Publisher
FRONTIERS MEDIA SA
DOI: 10.3389/fendo.2020.00303
Keywords
hypothalamic-pituitary-thyroid axis; hypothalamic-pituitary-gonad axis; testis size; Eurasian tree sparrow; plasma metabolites; breeding sub-stages
Categories
Funding
- National Natural Science Foundation of China (NSFC) [31672292, 31971413]
- NSFC [31770445]
Ask authors/readers for more resources
Reproduction is an energetically costly phenomenon. Therefore, to optimize reproductive success, male birds invest enough energetic resources for maintaining well-developed testes. The hypothalamic-pituitary-thyroid (HPT) axis in birds can crosstalk with the hypothalamic-pituitary-gonadal (HPG) axis, thus orchestrating both the reproduction and metabolism. However, until now, how the free-living birds timely optimize both the energy metabolism and reproduction via HPT-axis is not understood. To uncover this physiological mechanism, we investigated the relationships among body mass, testis size, plasma hormones including thyroid-stimulating hormone (TSH), thyroxine (T-4), triiodothyronine (T-3), metabolites including glucose (Glu), triglyceride (TG), total cholesterol (TC), uric acid (UA), diencephalon mRNA expressions of type 2 (Dio2) and 3 (Dio3) iodothyronine deiodinase enzymes, thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH), gonadotropin-releasing hormoneI(GnRH-I), and gonadotropin-inhibitory hormone (GnIH) in a male Eurasian tree sparrow (ETS,Passer montanus). We found significantly larger testis size; elevated diencephalonDio2andTRHmRNA expressions, plasma T-3, and UA levels; and significantly lowered Glu, TG, and TC levels during mating relative to the non-mating stages in male ETSs. However,Dio3, TSH, GnRH-I, andGnIHmRNA expression did not vary with the stage. Furthermore, life-history stage dependent variation in plasma T(3)had both direct effects on the available energy substrates and indirect effects on body mass and testis size, indicating a complex regulation of metabolic pathways through the HPT- and HPG-axes. The identified differences and relationships in mRNA expression, plasma T(3)and metabolites, and testis size in male ETSs contribute to our understanding how free-living birds adjust their molecular, endocrinal, and biochemical features to orchestrate their reproductive physiology and metabolism for the maintenance of well-developed testes.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available