New Findings Clarify Thyroid's Role in Mammalian Seasonal Changes

NEW ROCHELLE, N.Y. - Dec. 19, 2017 - PRLog -- Researchers now have a better understanding of the role that thyroid hormones, the tissues that produce them, and the biochemical pathways on which they act have in driving seasonal reproduction in some mammals, and how this new information may help explain seasonal changes in metabolism and mood that affect humans. The review article entitled "Seasonal Rhythms: The Role of Thyrotropin and Thyroid Hormones (http://online.liebertpub.com/doi/full/10.1089/thy.2017.0186)" is part of a special section on Japanese Research led by Guest Editor Yoshiharu Murata, Nagoya University, Japan, in the January 2018 issue of Thyroid, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers (http://www.liebertpub.com/) and the official journal of the American Thyroid Association (ATA). The article is available free on the Thyroid (http://www.liebertpub.com/thy) website until January 19, 2018.

Coauthors Tomoya Nakayama and Takashi Yoshimura, Nagoya University and National Institute for Basic Biology, Okazaki, Japan explore the significance and implications of the data derived from the most recent genomic and molecular studies of animals that breed seasonally, such as the Japanese quail. The researchers examine the relationship between length of daylight, the secretion of thyrotropin (TSH) from the pituitary gland, and gonadal growth in animals. They discuss the value of comparative studies in various mammals, in which molecules such as TSH have been conserved across evolution. These studies may help shed light on the mechanisms underlying seasonal depression-like symptoms and weight gain in humans.

"Through a series of very elegant studies, Dr. Yoshimura's group has discovered that T3 produced in the mediobasal hypothalamus (MBH) regulates gonadotropin-releasing hormone (GnRH) secretion in a seasonal fashion," says Peter A. Kopp, MD, Editor-in-Chief of Thyroid and Professor of Medicine, Division of Endocrinology, Metabolism, and Molecular Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL. "The increase in triiodothyronine (T3) is dependent on differential expression and activity of deiodinase type 2. Most interesting and surprising is the fact that the expression of deiodinase type 2 is regulated by TSH secreted from the pars tuberalis (rather than the pars distalis) of the anterior lobe of the pituitary gland. TSH secreted from this source differs in its glycosylation pattern and it does not stimulate the thyroidal TSH receptor. These studies define this alternative form of TSH as a springtime hormone and provide fundamental insights into the seasonal regulation of reproduction."

About the Journal
Thyroid (http://www.liebertpub.com/thy), the official journal of the American Thyroid Association (http://www.thyroid.org/), is an authoritative peer-reviewed journal published monthly online with open access options and in print. The Journal publishes original articles and timely reviews that reflect the rapidly advancing changes in our understanding of thyroid physiology and pathology, from the molecular biology of the cell to clinical management of thyroid disorders. Complete tables of content and a sample issue may be viewed on the Thyroid (http://www.liebertpub.com/thy) website. The complete Thyroid Journal Program includes the highly valued abstract and commentary publication Clinical Thyroidology, led by Editor-in-Chief Jerome M. Hershman, MD and published monthly, and the groundbreaking videojournal companion VideoEndocrinology, led by Editor Gerard Doherty, MD and published quarterly. Complete tables of content and sample issues may be viewed on the Thyroid (http://www.liebertpub.com/thy) website.

About the Society
The American Thyroid Association (ATA) (http://www.thyroid.org/) is the leading worldwide organization dedicated to the advancement, understanding, prevention, diagnosis, and treatment of thyroid disorders and thyroid cancer. ATA is an international membership medical society with over 1,700 members from 43 countries around the world. Celebrating its 94^th anniversary, the ATA delivers its mission — of being devoted to thyroid biology and to the prevention and treatment of thyroid disease through excellence in research, clinical care, education, and public health — through several key endeavors: the publication of highly regarded professional journals, Thyroid, Clinical Thyroidology, and VideoEndocrinology; annual scientific meetings; research grant programs for young investigators, biennial clinical and research symposia; support of online professional, public and patient educational programs; and the development of guidelines for clinical management of thyroid disease and thyroid cancer. The ATA promotes thyroid awareness and information through its online Clinical Thyroidology for the Public (distributed free of charge to over 11,000 patients and public subscribers) and extensive, authoritative explanations of thyroid disease and thyroid cancer in both English and Spanish. The ATA website (http://www.thyroid.org/) serves as the clinical resource for patients and the public who look for reliable information on the Internet.

About the Publisher
Mary Ann Liebert, Inc., publishers (http://www.liebertpub.com/) is a privately held, fully integrated media company known for establishing authoritative peer-reviewed journals in many promising areas of science and biomedical research, including Diabetes Technology & Therapeutics, Journal of Women's Health, and Metabolic Syndrome and Related Disorders. Its biotechnology trade magazine, GEN (Genetic Engineering & Biotechnology News), was the first in its field and is today the industry's most widely read publication worldwide. A complete list of the firm's more than 80 journals, books, and newsmagazines is available on the Mary Ann Liebert, Inc., publishers (http://www.liebertpub.com/) website.