Hormonal regulation of sociosexual behavior in female mammals.

The role of estrogen (E) and progesterone (P) in regulating the expression of agonistic, scent marking and proceptive displays is reviewed. In the intact sexually mature female, data indicate that agonistic, scent marking and proceptive patterns of behavior fluctuate significantly prior to and during the period of mating. The propensity to display a specific pattern of behavior is dependent upon the stimulus situation. Hence, agonistic behavior may be induced by the presence of a conspecific female whereas sexual behavior and proceptive responses will be elicited by a male. Administration of E to ovariectomized animals does not appear to produce significant effects on agonistic behavior and territorial scent-marking responses albeit in a few cases E appears to reduce agonistic tendencies toward male conspecifics. Exogenous E treatment, however, does appear to induce the occurrence of proceptive forms of scent-marking behavior as well as a variety of other proceptive responses which are further increased after P treatment. Importantly, the sequential administration of E and P facilitates both proceptive and copulatory responses in several rodent species. In addition, hormone implant studies indicate that sites in the brain which are sensitive to the hormonal facilitation of sexual receptivity concurrently facilitate proceptive behavior. On the basis of the current data, ovarian hormones appear to exert their strongest effects on producing behavioral displays which attract males prior to mating, facilitating sexual receptivity, and inducing concurrently proceptive responses which further enhance copulation and reproductive success.