Estradiol-17 beta silastic implants in female Rana ridibunda depress thyroid hormone concentrations in plasma and the in vitro 5'-monodeiodination activity of kidney homogenates

• Published in: General and comparative endocrinology Vol. 76; no. 3; p. 341
• Main Authors: Vandorpe, G, Kühn, E R
• Format: Journal Article
• Language: English
• Published: United States 01-12-1989
• Subjects: Animals; Drug Implants; Estradiol - pharmacology; Female; In Vitro Techniques; Iodide Peroxidase - metabolism; Kidney - drug effects; Kidney - metabolism; Rana ridibunda - metabolism; Ranidae - metabolism; Silicone Elastomers; Thyroid Hormones - blood; Thyroxine - blood; Triiodothyronine - blood
• ISSN: 0016-6480
• DOI: 10.1016/0016-6480(89)90127-5

Estradiol-17 beta containing silastic tubings were implanted in female Rana ridibunda. Preliminary data, concerning in vitro incubations of such tubings in saline media, revealed that high concentrations of estradiol were released out of the tubings in the incubation medium. Compared to control-implanted frogs, the frogs that had the estradiol tubings implanted for 30 days showed a significant increase of the plasma estradiol concentration, the ovarian estradiol concentration, and the weight of the oviduct. Plasma triiodothyronine (T3) levels, plasma thyroxine levels, and the in vitro T3 production in the kidney homogenates were significantly decreased. These results indicate that high estradiol levels not only influence the gonadal axis, but also cause important effects on the thyroidal axis.