title: Morpho-functional characteristics of rat fetal thyroid gland are affected by prenatal dexamethasone exposure.
abstract: Thyroid hormones (TH) and glucocorticoids strongly contribute to the maturation of fetal tissues in the preparation for extrauterine life. Influence of maternal dexamethasone (Dx) administration on thyroid glands morpho-functional characteristics of near term rat fetuses was investigated applying unbiased stereology. On the 16th day of pregnancy dams received 1.0mg/Dx/kg/b.w., followed by 0.5mg/Dx/kg/b.w. on the 17th and 18th days of gestation. The control females received the same volume of saline. The volume of fetal thyroid was estimated using Cavalieri's principle; the physical/fractionator design was applied for the determination of absolute number of follicular cells in mitosis and immunohistochemically labeled C cells; C cell volume was measured using the planar rotator. The functional activity of thyroid tissue was provided from thyroglobulin (Tg) and thyroperoxidase (TPO) immunohistochemical staining. Applying these design-based modern stereological methods it was shown that Dx treatment of gravid females led to a significant decrease of fetal thyroid gland volume in 19- and 21-day-old fetuses, due to decreased proliferation of follicular cells. The Tg and TPO immunohistochemistry demonstrated that intensive TH production starts and continues during the examined period in control and Dx-exposed fetuses. Under the influence of Dx the absolute number of C cells was lower in both groups of near term fetuses, although unchanged relation between the two populations of endocrine cells, follicular and C cells suggesting that structural relationships within the gland are preserved. In conclusion maternal glucocorticoid administration at the thyroid gland level exerts growth-inhibitory and maturational promoting effects in near term rat fetuses.
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, 142 despota Stefana Blvd., 11060 Belgrade, Serbia. Electronic address: manojlo@ibiss.bg.ac.rs.
authors.forename: Milica N
authors.initials: MN
authors.lastname: Manojlović-Stojanoski
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, 142 despota Stefana Blvd., 11060 Belgrade, Serbia.
authors.forename: Branko R
authors.initials: BR
authors.lastname: Filipović
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, 142 despota Stefana Blvd., 11060 Belgrade, Serbia.
authors.forename: Nataša M
authors.initials: NM
authors.lastname: Nestorović
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, 142 despota Stefana Blvd., 11060 Belgrade, Serbia.
authors.forename: Branka T
authors.initials: BT
authors.lastname: Šošić-Jurjević
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, 142 despota Stefana Blvd., 11060 Belgrade, Serbia.
authors.forename: Nataša M
authors.initials: NM
authors.lastname: Ristić
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, 142 despota Stefana Blvd., 11060 Belgrade, Serbia.
authors.forename: Svetlana L
authors.initials: SL
authors.lastname: Trifunović
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, 142 despota Stefana Blvd., 11060 Belgrade, Serbia.
authors.forename: Verica Lj
authors.initials: VLj
authors.lastname: Milošević
mesh_terms: D000818:Animals; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D018811:Maternal Exposure; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar; D013961:Thyroid Gland / Q000187:drug effects / Q000196:embryology* / Q000502:physiology
chemical_list: D003907:Dexamethasone
keywords: C cells; Dexamethasone; Fetal development; Follicular cells; Stereology; Thyroid