Roles of Thyroid, Adrenal and Pancreatic Hormones on Thyroid Activity of the Soft-shelled Turtles Lissemys punctata punctata Bonnoterre
Abstract:The effects of some exogenous peripheral hormones (thyroxine, corticosterone, epinephrine, norepinephrine and insulin) on thyroid activity were investigated in juvenile female soft-shelled turtles, Lissemys punctata punctata. Each hormone was injected in three different doses (25 g, 50 g or 100 g each per 100 g body weight, once daily at 9 AM) for 10 consecutive days. Thyroid activity was evaluated by gravimetry, histology (epithelial height) and thyroperoxidase assay. The findings revealed that thyroxine in low dose (25 g) stimulated thyroid activity by increasing the relative thyroid weight, epithelial height and thyroperoxidase activity, but inhibited gland activity at a high dose (100 g) by decreasing the values of all these parameters. The medium dose (50 g) had no significant effect. All other hormones, in all doses, significantly decreased thyroid activity by decreasing the values of all the parameters. Thyroid responses to exogenous hormones are generally dose-dependent in turtles. The mechanisms of actions of the hormones administered are suggested.
Document Type: Research Article
Publication date: 2006-09-01
More about this publication?
- Folia biologica is an international quarterly journal that publishes papers on the broad field of experimental zoology, nuclear and chromosome research, and also ultrastructural studies. All papers are subject to peer reviews. Indexed in: ISI Master Journal List, Current Contents, Polish Scientific Journals Contents. I.F. 0.667
- Editorial Board
- Information for Authors
- Ingenta Connect is not responsible for the content or availability of external websites