title: Citrus flavanones mildly interfere with pituitary-thyroid axis in old-aged male rats.
abstract: Citrus flavanones naringenin (NAR) and hesperetin (HES) are potent antioxidants that may contribute to maintenance of health at old age by improving cardiovascular and metabolic status. However, they may also affect thyroid hormone economy. Keeping in mind impaired thyroid function at older age, in this study we tested wheather NAR or HES administration potentiate this decline. NAR or HES were administrated orally (15mg/kg) to male 24-month-old Wistar rats during 4 weeks. Control groups received vehicle, sunflower oil. Qualitative and quantitative immunohistochemical and immunofluorescent expression of specific proteins and stereological analyses of thyroid tissue were performed. Thyroid stimulating hormone (TSH) and total thyroxine (T4) concentrations were measured in serum. Thyroid parenchyma of both flavanone-treated groups was characterized by lower (p<0.05) absolute and relative volume of luminal colloid, accompanied by elevated (p<0.05) relative volume of stroma in comparison with the controls. No hypertrophy or absolute thyroid volume change was detected. Intensity of immunopositive signal for thyroglobulin (Tg) and T4bound to Tg (T4-Tg) increased (p<0.05) in the colloid of thyroid follicles after both flavanone treatments. Serum TSH increased (p<0.05) after NAR, while T4remained unchanged after both treatments. In conclusion, NAR elevated serum TSH in old-aged males, thus being more potent than HES in altering pituitary-thyroid axis. However, changes in thyroid structure, namely moderate colloid depletion and higher Tg and T4-Tg protein expressions after both treatments, indicate preserved capacity of the gland to compensate flavanone interfering, and maintain T4production in old-aged males.
authors.affiliation: Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia. Electronic address: marko.miler@ibiss.bg.ac.rs.
authors.forename: Marko
authors.initials: M
authors.lastname: Miler
authors.affiliation: Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Jarić
authors.affiliation: Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia.
authors.forename: Jasmina
authors.initials: J
authors.lastname: Živanović
authors.affiliation: Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia.
authors.forename: Vladimir
authors.initials: V
authors.lastname: Ajdžanović
authors.affiliation: Department of Radiobiology and Molecular Genetics, Institute of Nuclear Sciences "Vinča", University of Belgrade, Belgrade, Serbia.
authors.forename: Nasta
authors.initials: N
authors.lastname: Tanić
authors.affiliation: Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia.
authors.forename: Verica
authors.initials: V
authors.lastname: Milošević
authors.affiliation: Department of Cytology, Institute for Biological Research "Siniša Stanković", University of Belgrade, Belgrade, Serbia.
authors.forename: Branka
authors.initials: B
authors.lastname: Šošić-Jurjević
mesh_terms: D000367:Age Factors; D000818:Animals; D002957:Citrus; D004195:Disease Models, Animal; D044950:Flavanones / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006728:Hormones / Q000097:blood / Q000235:genetics; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects*; D007150:Immunohistochemistry; D008297:Male; D010902:Pituitary Gland / Q000187:drug effects / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D013961:Thyroid Gland / Q000187:drug effects / Q000473:pathology
chemical_list: D044950:Flavanones; D006728:Hormones
keywords: Citrus flavanones; Old age; Qualitative and quantitative histology; Rats; Thyroid