Circadian rhythms in adrenal adrenaline and noradrenaline and in blood glucose levels in the bandicoot rat (Bandicota bengalensis).

The aim of the present investigation was to ascertain circadian rhythms in adrenomedullary hormones and blood glucose level in the adult male bandicoot rat. Adrenomedullary hormones and blood glucose were measured during 0600 h, 1200 h, 1800 h and 2400 h of a 24-hour period from different groups of animals. Adrenaline, noradrenaline and blood glucose levels increased during 2400 h through 0600 h and decreased during 1200 h through 1800 h. The finding indicates that there is a circadian rhythm in adrenomedullary hormones and blood glucose level in the bandicoot rat. It is suggested that circadian fluctuation in these substances may be due to diurnal variation in the activity of the animals.