Journal
PROCEEDINGS OF THE JAPAN ACADEMY SERIES B-PHYSICAL AND BIOLOGICAL SCIENCES
Volume 95, Issue 7, Pages 343-357Publisher
JAPAN ACAD
DOI: 10.2183/pjab.95.025
Keywords
photoperiodism; circadian clock; thyrotropin; thyroid hormone; photoreceptor; opsin
Categories
Funding
- JSPS KAKENHI [26000013, 17F17107]
- Human Frontier Science Program [RGP0030/2015]
- World Premier International Research Center Initiative (WPI), MEXT, Japan
- Grants-in-Aid for Scientific Research [17F17107] Funding Source: KAKEN
Ask authors/readers for more resources
Animals make use of changes in photoperiod to adapt their physiology to the forthcoming breeding season. Comparative studies have contributed to our understanding of the mechanisms of seasonal reproduction in vertebrates. Birds are excellent models for studying these phenomena because of their rapid and dramatic responses to changes in photoperiod. Deep brain photoreceptors in birds perceive and transmit light information to the pars tuberalis (PT) in the pituitary gland, where the thyroid-stimulating hormone (TSH) is produced. This PT-TSH locally increases the level of the bioactive thyroid hormone T-3 via the induction of type 2 deiodinase production in the mediobasal hypothalamus, and an increased T-3 level, in turn, controls seasonal gonadotropin-releasing hormone secretion. In mammals, the eyes are the only photoreceptive structure, and nocturnal melatonin secretion encodes day-length information and regulates the PT-TSH signaling cascade. In Salmonidae, the saccus vasculosus plays a pivotal role as a photoperiodic sensor. Together, these studies have uncovered the universality and diversity of fundamental traits in vertebrates.
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