✦ LIBER ✦
Plasma prolactin, thyroxine, triiodothyronine, testosterone, and luteinizing hormone during a photoinduced reproductive cycle in mallard drakes
✍ Scribed by Sharp, P. J. ;Klandorf, H. ;McNeilly, A. S.
- Publisher
- John Wiley and Sons
- Year
- 1986
- Tongue
- English
- Weight
- 486 KB
- Volume
- 238
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
The temporal relationships between plasma concentrations of prolactin, thyroxine (T4) and triiodothyronine (T3) were determined in a group of six wild mallard drakes during the development and maintenance of longday refractoriness after transfer from 6 h light: 18 h darkness (6L:18D) to 20L:4D for 24 weeks. As shown by changes in the plasma concentrations of luteinizing hormone (LH) and testosterone, the birds came into breeding condition and then became long-day refractory within 5 weeks of photostimulation. Long-day refractoriness was maintained for the remainder of the study.