KAPLAN, PETER L.

Twenty-six 75-day-old, ovariectomized Long-Evans female
rats were randomly divided into two groups of ten and one
group of six animals. The ten Group I Ss received, in consecutive
treatment periods, 2 mg progesterone (P-2) daily,
2 mg testosterone propiorate (TP-2) daily, TP-2 daily plus
P-2 every fourth day, and P-2 every fourth day. The ten Group
II Ss received, in consecutive treatment periods, P-2 every
fourth day, and 4 mg dihydrotestosterone (DHT-4) daily plus
P-2 every fourth day. Both Groups I and II were tested for
female sexual behavior. A significant increase in the lordosis
response was observed only in Group I Ss after receiving TP-2
plus P-2 every fourth day. Group III Ss were tested for male
sexual behavior after receiving DHT-4 daily. Male sexual
behavior increased significantly after DHT-4 treatments. It
was concluded that progesterone exerts a facilitatory effect
on female sexual behavior only when the Ss have been previously
primed with an aromatizable androgen and that dihydrotestosterone
is capable of inducing male sexual behavior in female rats.