title: Melatonin in the thyroid gland: regulation by thyroid-stimulating hormone and role in thyroglobulin gene expression.
abstract: Melatonin is an indoleamine with multiple functions in both plant and animal species. In addition to data in literature describing many other important roles for melatonin, such as antioxidant, circadian rhythm controlling, anti-aging, antiproliferative or immunomodulatory activities, our group recently reported that thyroid C-cells synthesize melatonin and suggested a paracrine role for this molecule in the regulation of thyroid activity. To discern the role played by melatonin at thyroid level and its involvement in the hypothalamic-pituitary-thyroid axis, in the present study we have analyzed the effect of thyrotropin in the regulation of the enzymatic machinery for melatonin biosynthesis in C cells as well as the effect of melatonin in the regulation of thyroid hormone biosynthesis in thyrocytes. Our results show that the key enzymes for melatonin biosynthesis (AANAT and ASMT) are regulated by thyroid-stimulating hormone. Furthermore, exogenous melatonin increases thyroglobulin expression at mRNA and protein levels on cultured thyrocytes and this effect is not strictly mediated by the upregulation of TTF1 or, noteworthy, PAX8 transcription factors. The present data show that thyroid C-cells synthesize melatonin under thyroid-stimulating hormone control and, consistently with previous data, support the hypothesis of a paracrine role for C-cell-synthesised melatonin within the thyroid gland. Additionally, in the present study we show evidence for the involvement of melatonin in thyroid function by directly-regulating thyroglobulin gene expression in follicular cells.
authors.affiliation: University of Seville, School of Medicine, Department of Normal and Pathological Cytology and Histology, Seville, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Garcia-Marin
authors.affiliation: University of Seville, School of Medicine, Department of Normal and Pathological Cytology and Histology, Seville, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Fernandez-Santos
authors.affiliation: University of Seville, School of Medicine, Department of Normal and Pathological Cytology and Histology, Seville, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Morillo-Bernal
authors.affiliation: University of Seville, School of Medicine, Department of Normal and Pathological Cytology and Histology, Seville, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Gordillo-Martinez
authors.affiliation: University of Seville, School of Medicine, Department of Normal and Pathological Cytology and Histology, Seville, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Vazquez-Roman
authors.affiliation: University of Seville, School of Medicine, Department of Normal and Pathological Cytology and Histology, Seville, Spain.
authors.forename: J C
authors.initials: JC
authors.lastname: Utrilla
authors.affiliation: Institute of Biomedicine of Seville, Laboratory of Molecular NeuroImmunoEndocrinology, Seville, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Carrillo-Vico
authors.affiliation: Institute of Biomedicine of Seville, Laboratory of Molecular NeuroImmunoEndocrinology, Seville, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Guerrero
authors.affiliation: University of Seville, School of Medicine, Department of Normal and Pathological Cytology and Histology, Seville, Spain. ilacave@us.es.
authors.forename: I
authors.initials: I
authors.lastname: Martin-Lacave
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation / Q000235:genetics; D008297:Male; D008550:Melatonin / Q000096:biosynthesis / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013954:Thyroglobulin / Q000235:genetics / Q000378:metabolism*; D013961:Thyroid Gland / Q000166:cytology / Q000502:physiology*; D013963:Thyroid Hormones / Q000096:biosynthesis / Q000378:metabolism; D013972:Thyrotropin / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D013963:Thyroid Hormones; D013972:Thyrotropin; D013954:Thyroglobulin; D008550:Melatonin