Persistent erection (priapism) for months with concomitant infertility in rats due to protein-energy-malnutrition.

Male Sprague Dawley rats were fed ad lib. semi-synthetic diets, containing 9% casein-protein (I) or 9% bread crust-protein (II), and the control diet in restricted amounts (III), respectively. After 6 weeks persistent erections were observed in groups II and III. 93% of the crust-fed animals and 67% of the pair-fed-group developed priapism within 22 weeks. All persistent erections disappeared after an ad lib. casein-refeeding period.