title: Testosterone and estradiol treatments differently affect pituitary-thyroid axis and liver deiodinase 1 activity in orchidectomized middle-aged rats.
abstract: We previously reported that orchidectomy (Orx) of middle-aged rats (15-16-month-old; MA) slightly affected pituitary-thyroid axis, but decreased liver deiodinase (Dio) type 1 and pituitary Dio2 enzyme activities. At present, we examined the effects of subsequent testosterone-propionate treatment (5mg/kg; Orx+T), and compared the effects of testosterone with the effects of estradiol-dipropionate (0.06mg/kg; Orx+E) treatment. Hormones were subcutaneously administered, daily, for three weeks, while Orx and sham-operated (SO) controls received only the vehicle. The applied dose of T did not alter serum TSH, T4 and T3 concentrations in Orx- MA, though it increased TSH when administrated to Orx young adults (2.5-month-old; Orx-YA). However, pituitaries of Orx-MA+T rats had higher relative intensity of immunofluorescence (RIF) for TSHβ; in their thyroids we found increased volume and height of follicular epithelium, decreased volume of the colloid and higher RIF for T4-bound to thyroglobulin (Tg-T4). Liver Dio1 activity was increased. E-treatment did not affect serum hormone levels, pituitary RIF for TSHβ, or liver Dio1 activity in Orx-MA rats. Thyroids had decreased relative volume and height of follicular epithelium, increased relative volume of the colloid, decreased volume of sodium-iodide symporter-immunopositive epithelium and lower RIF for Tg-T4. Detected changes were statistically significant. In conclusion, androgenization enhanced pituitary TSHβ RIF, thyroid activation and liver Dio1 enzyme activity in Orx-MA, without elevating serum TSH as in Orx-YA rats. Estrogenization induced pituitary enlargement with no effect on pituitary TSHβ RIF, serum TSH or liver Dio1 activity. E also induced alterations in thyroid histology that indicate mild suppression of its functioning, and contributed to thyroid blood vessel enlargement in Orx-MA rats.
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade, Serbia. Electronic address: brankasj@ibiss.bg.ac.rs.
authors.forename: B
authors.initials: B
authors.lastname: Šošić-Jurjević
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade, Serbia.
authors.forename: B
authors.initials: B
authors.lastname: Filipović
authors.affiliation: Institut für Experimentelle Endokrinologie, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Renko
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade, Serbia.
authors.forename: M
authors.initials: M
authors.lastname: Miler
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade, Serbia.
authors.forename: S
authors.initials: S
authors.lastname: Trifunović
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade, Serbia.
authors.forename: V
authors.initials: V
authors.lastname: Ajdžanovič
authors.affiliation: Institut für Experimentelle Endokrinologie, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, D-13353 Berlin, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Kӧhrle
authors.affiliation: Institute for Biological Research "Siniša Stanković", University of Belgrade, Despot Stefan Blvd. 142, 11000 Belgrade, Serbia.
authors.forename: V
authors.initials: V
authors.lastname: Milošević
mesh_terms: D000375:Aging; D000818:Animals; D001835:Body Weight; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives*; D007150:Immunohistochemistry; D007453:Iodide Peroxidase / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D008297:Male; D009919:Orchiectomy; D010902:Pituitary Gland / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D013739:Testosterone / Q000008:administration & dosage*; D013961:Thyroid Gland / Q000473:pathology*; D013972:Thyrotropin / Q000097:blood*; D013974:Thyroxine / Q000097:blood
chemical_list: D013739:Testosterone; D004958:Estradiol; D013972:Thyrotropin; C109812:iodothyronine deiodinase type I; D007453:Iodide Peroxidase; C023482:estradiol dipropionate; D013974:Thyroxine
keywords: Estradiol; Middle age; Pituitary-thyroid axis; Rat; Testosterone