The effects of caloric restriction and age on thyroid hormone signalling in the heart of rats

Interdependence of the peripheral metabolism of glucocorticoids and thyroid hormones under calorie deficit in rats at different ages

“…We have not found previous reports on the effect of age on DIO1 or DIO3 liver expression. In our experiment, however, we observed a higher plasma fT3 concentration in younger rats, which could reflect higher DIO1 activity in this group (Lachowicz et al, 2014). On the other hand, rodent liver DIO1 activity was reduced by 40% calorie restriction introduced for 30 days (Araujo et al, 2008) or for 25 days (Araujo et al, 2009) and by 24-h fasting (Aceves et al, 2003), or was not changed by 24-h fasting (Boelen et al, 2012), while DIO1 mRNA remained unaffected by 24-h fasting (Aceves et al, 2003;Boelen et al, 2012).…”

“…The present paper is the second report from an experiment whose results were described previously (Lachowicz et al, 2014). The 9-week experiment was performed on 42 adult male Sprague-Dawley rats obtained from the Mossakowski Medical Research Centre, Polish Academy of Science, Warsaw (Poland).…”

Effects of Dietary Protein on Thyroid Axis Activity

“…In the study conducted on rats, the influence of a normal-protein and calorie-restricted diet on thyroid hormone levels has been shown to depend on age. In 17-week old rats, a decrease in TSH level, both total and free fraction of T3 and T4 was observed, whereas in 44-week old animals only T4, free T4 (fT4) and fT3 serum levels were affected by energy restriction [ 31 ]. Both caloric restriction connected with lower carbohydrate content as well as the higher protein to carbohydrate ratio could be the cause of these effects.…”

Морфологические Изменения Щитовидной Железы Крыс После Интервального Голодания

“…Так, у животных, получавших сниженный рацион, заметили, что концентрация тироксина (Т 4 ) в сыворотке крови не изменялась, концентрация трийодтиронина (Т 3 ) снижалась, а обратного (реверсивного) Т 3 , наоборот, увеличивалась [7]. Другие ученые обнаружили снижение всех гормонов ЩЖ в крови после воздействия ограниченного питания [8,[16][17][18]. В то же время некоторые исследователи наблюдали, что после воздействия месячной низкокалорийной диеты содержание Т 3 и Т 4 в крови существенно возрастает, а концентрация тиреотропного гормона, наоборот, снижается [9].…”