== PNAS == 

 It would have been more helpful if you had read WP:MEDRS fully before leaving a message on my talkpage. PNAS is indeed a high-quality journal and heavily cited in the scientific community, but that doesn't make it an ideal source from the perspective of a general purpose encyclopedia. Clearly, the study in question does a lot in explaining that the effects of thyroid hormones may actually be mediated by autonomous nervous system activity. But it is, together with PMID 18182466, a very early study into this phenomenon. It would need to be reproduced, perhaps in different models, before becoming suitable for inclusion into a general encyclopedia. In such a case, it would be much preferable to cite a secondary source (e.g. a review or a textbook chapter) that puts this interesting study in a wider perspective. 

 I hope this clarifies matters. Please have a look at WP:MEDRS again and let me know if there are any outstanding issues.  | 