Prolactin-induced gain in body weight in relation to caloric intake and energy expenditure in spotted munia

Prolactin, which induced significant gain in body weight and in the weight of the cervical and abdominal fat deposits had no effect on daily total food intake in spotted munia. The hormone changed the feeding pattern from a modal type to almost continuous feeding, increased whole body oxygen consumption of the birds, and had no effect on total hopping index. Prolactin-induced fattening, therefore seems due to neither an increased caloric intake, nor a decreased metabolic expenditure, but probably reflects better utilization of food.