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Binding pattern of 125iodine thyroxine and tri-iodothyronine in skin and liver tissues of spotted munia, Lonchura punctulata: co-relation to seasonal cycles of breeding and molting.
MedLine Citation:
PMID:  24851410     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
Prevalent notion about thyroid hormones is that thyroxine (T4) is a mere precursor and physiological effects of thyroid hormones are elicited by tri-iodothyronine (T3) after mono-deiodination of T4. Earlier studies on feather regeneration and molt done on spotted munia L. punctulata suggest that T4 (mono-deiodination suppressed by iopanoic acid and thyroidectomized birds) is more effective than T3 in inducing feather regeneration. The binding pattern of 125I labeled T4 and T3 has been investigated in the nuclei prepared from skin and liver tissues (samples obtained during different months) of spotted munia using scatchard plot analysis. The results show that binding capacity (B(max)--pmole/80 microgm DNA) of 125I-T3 to nuclei of skin was significantly higher in November as compared to April and June, whereas the binding affinity (Kd-10(-9)M(-1)) was significantly lower in November as compared to April and June. During November, B(max) for binding of T3 and T4 did not vary in liver and skin nuclei but Kd varied significantly. Binding capacity of 125I- T3 to skin and liver did not vary but binding affinity of 125I- T4 to skin was approximately 7 times higher than that of liver. The results suggest that T4 does show a variation in binding pattern that co-relates to the molting pattern of spotted munia. These variations might play important role in different physiological phenomenon in this tropical bird. The experiments do point towards the possibility of independent role of T4 as a hormone, however, further experiments need to be done to ascertain the role of T4 in this model and work out the exact molecular mechanism of action.
Authors:
Ashish Thapliyal; Asha Chandola-Saklani; Dinesh Bhatt; Prashant Anthwal
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Indian journal of experimental biology     Volume:  52     ISSN:  0019-5189     ISO Abbreviation:  Indian J. Exp. Biol.     Publication Date:  2014 May 
Date Detail:
Created Date:  2014-05-23     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0233411     Medline TA:  Indian J Exp Biol     Country:  India    
Other Details:
Languages:  eng     Pagination:  478-88     Citation Subset:  IM    
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