Abstract
Thyroid hormone secretion rate (TSR) of female golden hamsters and male Sprague-Dawley-Rolfsmeyer rats at 25 days of age were estimated as 0.75 μg L-T4/100 g body weight and 1.41 μg L-T4/100 g body weight respectively. The mean TSR of control group of both hamster and male rat reduced at 55 days (0.60 and 1.20 μg L-T4/100 g body weight, respectively) gives further evidence of aging. In hamsters, melatonin treatment at higher levels had no greater depressing effect upon TSR than the lower level, but had greater effect on food consumption. However, in male rats, melatonin depressed TSR at the higher level only. It seems that hamster is more sensitive to melatonin than rats. Thus the lower level exerts a maximum effect whereas in the rat, higher levels are required for maximum effect.

This publication has 0 references indexed in Scilit: