Photoperiod-adrenal Interactions on Carbohydrate Metabolism in the Feral Pigeon during the Recrudescent Phase

The possible influence of photoperiodism on carbohydrate metabolism has been evaluated in the feral pigeons. Both Dexamethasone (DXM) and Corticosterone (CORT) treated pigeons were exposed to NDL or LD 18:6 photoperiodic schedules and their tissue glycogen contents, blood glucose and hepatic phosphorylase and G-6-P’ase activity assayed. Both DXM & Corticosterone treatment increased tissue glycogen content under both photic schedules. Plasma glucose level increased under LD 18:6 while, CORT treatment decreased and, DXM treatment increased further the glycemic level under both photic schedules. The activity of hepatic phosphorylase decreased in all experimental birds while that of G-6-P’ase increased. From the results it can be concluded that gonadal recrudescence induces depletion of tissue glycogen content and hyperglycemic, which are potentiated by long photic schedule. Chronic adreno-cortical suppression or activation has differential effects on glycemic status probably through their action on glucoregulatory center or by the altering mechanism involved in glucose absorption, uptake and utilization.