Physiological response to central and peripheral injection of prostaglandin D2 in chicks

Prostaglandin D2 (PGD2) is associated with a diverse array of functions in mammals including regulation of appetite, body temperature, sleep, and immune responses. Although much is known about the effects of PGD2 in mammals, there is a lack of information about its effects in birds. Therefore, the purpose of the present study was to determine if intracerebroventricular (ICV) and intraperitoneal (IP) injections of PGD2 affect feeding, voluntary movement, crop-emptying rate, corticosterone release, and cloacal temperature in chicks (Gallus gallus). ICV injection of PGD2 was associated with a reduction in food intake, a reduction in voluntary movement, an increase in the time spent sitting, a decline in crop emptying rate, and also short-term hypothermia. Central injection of PGD2 also decreased the plasma glucose concentration in chicks while it tended to increase the plasma corticosterone concentration. On the other hand, except for crop emptying, such physiological changes are not observed after IP injection of PGD2. In sum, the present study suggests that PGD2 induces anorexia, change in behavior, decline in crop empting rate, hypoglycemia and hypothermia, but most of these effects are exerted via central nervous system in chicks.