Abstract
In birds, changes in hypothalamic gonadotropin-releasing hormone-I (GnRH-I) content and release are correlated with reproductive stages. This study examined the distribution and expression level of GnRH-I mRNA in anatomically discrete hypothalamic nuclei throughout the turkey reproductive cycle and following photostimulation. GnRH-I mRNA expression was determined using in situ hybridization in non-photostimulated (NPS), egg-laying (LAY), incubating (INC) and photorefractory (REF) hens. Overall, GnRH-I mRNA expression was greatest in the nucleus commissurae pallii (nCPa) and around the organum vasculosum lamina terminalis (OVLT), with less expression observed in the nucleus septalis lateralis (SL), cortico-habenula cortico-septum area, and within the nucleus preopticus medialis. GnRH-I mRNA expression was significantly increased in nCPa, OVLT, and SL after NPS hens (6L:18D) were exposed to a 30 or 90 min pulse of light beginning 14 h after first light (dawn). GnRH-I mRNA abundance within nCPa, OVLT and SL was greater in LAY than in NPS and INC hens, while mRNA expression was least in REF hens. These results indicate that GnRH-I mRNA expression in birds is sensitive to light stimulation during the photosensitive period and can be used to more precisely characterize their different reproductive stages.
| Original language | English |
|---|---|
| Pages (from-to) | 91-99 |
| Number of pages | 9 |
| Journal | General and Comparative Endocrinology |
| Volume | 146 |
| Issue number | 2 |
| State | Published - Apr 2006 |
Bibliographical note
Funding Information:We thank I. C. Dunn for providing of cGnRH-I cDNA, and O. M. Youngren for comments on the manuscript. This research was supported by Research Grant No. US-3399-03C from BARD, The United States–Israel Bionational Agricultural Research and Development Fund.
Keywords
- Avian hypothalamus
- GnRH-I mRNA expression
- In situ hybridization
- Photostimulation
- Turkey reproductive cycle
