Mole-Rats, Thyroid Hormones
Yet more naked mole-rats in this research on thyroid hormone levels and longevity in rodents, via EurekAlert! This one raises more more questions than it answers: "The thyroid gland produces thyroxine (T4) which converts to triiodothyronine (T3) in the presence of iodine. T3 is the active component of T4 and is the key hormone in regulating metabolism ... T4 levels varied significantly between all of the groups, with the shorter-lived groups having higher levels of T4 than longer-lived groups. The mice, for example, had twice as much T4 as the Damara mole-rats and had and three times more than that of the naked mole-rats ... There was also a significant difference in T3 levels between the naked mole-rats and the guinea pigs." To put this in an interesting context, it has been shown that calorie restriction lowers levels of T3. A complicated thing, metabolism. This is why I support efforts to identify and fix cellular damage (easier, more effective) rather than tinkering with metabolic processes (harder, less effective).
Link: http://www.eurekalert.org/pub_releases/2006-10/aps-lrh100706.php