Recovery of exploratory capacity after ectopic pituitary homografts in Snell Dwarf mice (dw/dw).

The effects of ectopic pituitary homografts on free behavior were studied over a period of one month in adult Snell Dwarf mice. Because of anterohypophyseal deficiency, these animals exhibit dwarfism, sterility, and marked behavioral deficits. Beginning on the 16th day after surgery, in addition to a considerable weight gain, grafts result in the total disappearance of inactivity with passive social contact--the behavior most frequently observed in the mutants--to be replaced only by exploration--the most frequently observed behavior in controls. The treatment totally restores the latter behavior. Specific hormonal treatments and biochemical manipulations at different stages would enable identification of the hypophyseal hormones and/or the growth factors involved in the behavioral and morphological changes.