Morphological and Functional Changes in Pituitary-Thyroid Axis Following Prolonged Exposure of Female Rats to Constant Light
2014
Аутори:
Miler, MarkoŠošić-Jurjević, Branka
Nestorović, Nataša
Ristić, Nataša
Jarić, Ivana
Savin, Svetlana
Milošević, Verica
Тип документа:
Чланак у часопису (Објављена верзија)
,
© 2014 Wiley Periodicals, Inc.
Метаподаци
Приказ свих података о документуАпстракт:
Light regulates numerous physiological functions and synchronizes them
with the environment, in part by adjusting secretion of different
hormones. We hypothesized that constant light (CL) would disturb
pituitary-thyroid axis. Our aim was to determine morphological and
functional changes in this endocrine system in such extreme conditions
and, based on the obtained results, to propose the underlying
mechanism(s). Starting from the thirtieth postnatal day, female Wistar
rats were exposed to CL (600 lx) for the following 95 days. The controls
were maintained under the regular laboratory lighting conditions. After
decapitation, pituitaries and thyroids were prepared for further
histomorphometric, immunohistochemical, and immunofluorescence
examinations. Concentration of thyroid stimulating hormone (TSH), total
T4 and T3 (TH) were determined. Thyroid tissue of light-treated rats was
characterized by microfollicular structure. We detected no change in
total thyroid volume, localization and accumulation of thyroglobulin,
thyroid peroxidase, and sodium-iodide symporter in the follicular
epithelium of CL rats. The volume of follicular epithelium and
activation index were increased, while volume of the colloid and serum
levels of TH decreased. In the pituitary, the relative intensity of TSH
beta-immunofluorescence signal within the cytoplasm of thyrotrophs
increased, but their average cell volume and the relative volume density
decreased. Serum TSH was unaltered. We conclude that exposure of female
rats to CL induced alterations in pituitary-thyroid axis. Thyroid tissue
was characterized by microfollicular structure. Serum TH levels were
reduced without accompanying increase in serum TSH. We hypothesize that
increased secretion and clearance of TH together with unchanged or even
decreased hormonal synthesis, resulted in decreased serum TH levels in
CL group. We assume this decrease consequently led to increased
synthesis and/or accumulation of pituitary TSH. However, decreased
average TSH cell volume and relative volume density, together with
unchanged serum TSH, point to additional, negative regulation of
thyrotrophs. (C) 2014 Wiley Periodicals, Inc.
Кључне речи:
rat; thyroid; pituitary; immunohistochemistry; constant lightИзвор:
Journal of Morphology, 2014, 275, 10, 1161-1172Финансирање / пројекти:
- Одговор неуроендокриног система пацова на одабране биљне екстракте, фитоестрогене, стероидне и пептидне хормоне (RS-MESTD-Basic Research (BR or ON)-173009)
DOI: 10.1002/jmor.20293
ISSN: 1097-4687
PubMed: 24797691
WoS: 000340671200005
Scopus: 2-s2.0-84906057157
URI
https://radar.ibiss.bg.ac.rs/handle/123456789/2158http://onlinelibrary.wiley.com/doi/10.1002/jmor.20293/abstract