Abstract
Tilapias are emerging as one of the most important fish in worldwide aquaculture and are also widely used as model fish in the study of reproduction and behavior. During the reproductive season, male tilapia are highly territorial and form spawning pits in which the dominant males court and spawn with available females. Non-territorial males stand a much lower chance of reproducing. Using transgenic tilapia in which follicle stimulating hormone (FSH) gonadotrophs were fluorescently labeled with enhanced green fluorescent protein (EGFP), we studied the effect of social dominance on the hormonal profile and pituitary cell populations in dominant and non-dominant males. Immunofluorescence studies showed that FSH-EGFP-transgenic fish reliably express EGFP in FSH-secreting cells. EGFP expression pattern differed from that of luteinizing hormone. Dominant males had larger gonads as well as higher levels of androgens and gonadotropins in the plasma. Pituitaries of dominant males exhibited higher gonadotropin content and gene expression. Flow cytometry revealed pituitary hyperplasia as well as FSH cell hyperplasia and increased granulation. Taken together, these findings suggest that gonadotroph hyperplasia as well as increased production by individual cells underlie the increased reproductive activity of dominant tilapia males.
Original language | English |
---|---|
Pages (from-to) | 126-135 |
Number of pages | 10 |
Journal | General and Comparative Endocrinology |
Volume | 192 |
DOIs | |
State | Published - 1 Oct 2013 |
Bibliographical note
Funding Information:The authors would like to acknowledge Prof. Koichi Kawakami for the permission to use the tol2 system and Dr. Chi-Bin Chien for kindly providing the tol2kit plasmids. This research was supported by Grant No. 1350/06 from the Israel Science Foundation (ISF) . Matan Golan’s research was generously supported by the Hoffman Leadership and Responsibility fund, at the Hebrew University.
Keywords
- FSH
- Gonadotroph
- Hyperplasia
- Social status
- Tilapia
- Tol2