Oviposition pattern of Japanese quail following hypothalamic lesioning with super-absorbent polymer

Abstract

The functions of two hypothalamic areas in controlling the female reproductive cycle were investigated by the intracerebral injection of a new type of water-absorbent polymer of high capacity (super-absorbent polymer). After injection of a minute amount of the polymer into the brain tissue, bulging of the polymer produces a discrete lesion at the site of injection. Two lines (T- and J-lines) of Japanese quail were used; T-line, having a characteristic free-running oviposition pattern irrespective of the environmental 14L10D, and J-line, having a regular oviposition pattern which synchronized with 14L10D. Lesions at the preoptic area were without effect in birds of J-line, but the oviposition of T-line was changed from free-running to regular. Lesions at the posterodorsal part of the infundibular complex were without effect in T-line, but the regular oviposition pattern of J-line became free-running. These results suggest that relative dominancy between the two hypothalamic areas may determine basic pattern of oviposition through modification of the ovulation cycle.