HORMONES AND MATING BEHAVIOR 



1195 



when estrone was given was intromission 

 achieved by some animals. Clearly estrone 

 was a better substitute for testosterone 

 propionate than estradiol, but not even 

 this substance substituted completely. 



Male cats appear to be different. The re- 

 sponse to 6000 R.U. of estradiol or to 1 

 to 5 mg. stilbestrol was normal, provided 

 castration had been performed recently. 

 Otherwise, not even testosterone propionate 

 was effective (Green, Clemente and de 

 Groot, 1957). 



Relationship 3. The display of feminine 

 responses by intact untreated male mon- 

 keys, rats, lizards, fishes, pigeons, hamsters, 

 and rabbits has been noted (p. 1179). In a 

 rat displaying this behavior spontaneously, 

 histologic examination of the testes and 

 seminal vesicles indicated that sperma- 

 togenic and androgenic activity were normal 

 (Beach, 1945a). Castration was followed by 

 an immediate loss of the female response, 

 but after an interval and following the in- 

 jection of testosterone propionate, the fre- 

 fiuency of lordosis and hopping compared 

 favorably with that seen preoperatively. 

 Presumably, therefore, the feminine be- 

 havior was shown in response to androgenic 

 stimulation of testicular origin. As Beach 

 stated, cases of this kind are not common. In 

 our opinion they correspond to the much 

 more frequently occurring relationship 7 in 

 which estrogenic substances are responsible 

 for the masculine behavior displayed by 

 females. 



Elsewhere it is reported that 7 of 8 intact 

 male rats displayed elements of the female 

 pattern of behavior following injections of 

 10 to 23 mg. testosterone i)ropionate (Beach, 

 1941 L The responses were observed fre- 

 (luently enough to assure Beach of their 

 presence, but they were described as being 

 difficult to elicit, sluggishly performed, and 

 quickly terminated. Two of 4 male mice 

 showed lordosis during injections of 2 mg. 

 of testosterone proportionate over a 7-day 

 period (Engel, 1942). Male lizards receiv- 

 ing testosterone propionate displayed ele- 

 ments of the female pattern of behavior, 

 l)rovided they were subordinate during 

 fights within the group (Noble and Green- 

 berg, 1941a). In neither of the last two 

 studies were quantitative data given. 



Relationship 4- Injections of estrogens 

 into male laughing gulls stimulate them to 

 respond to the sex call of the males and to 

 "food beg" with lowered head, a posture 

 necessary for copulation of the female with 

 the male (Noble and Wurm, 1940b). The 

 male herring gull appears to react less 

 definitely. Injections of stilbestrol into the 

 eggs fairly early in incubation and into the 

 birds for 22 months after hatching had little 

 effect on the behavior of three males. Three 

 weeks after the injections were discontinued 

 their activity approached that of many 

 testosterone-injected male birds (Boss, 

 1943). Some castrated male rats and guinea 

 pigs receiving implants of ovaries (Steinach, 

 1912), and some intact and castrated male 

 rats and mice treated wdth estrogens dis- 

 played feminine behavior (Kun, 1934; Ball, 

 1939; Engel, 1942). In Ball's experiments 

 pellets of estrone were without effect, but 

 8600 R.U. estradiol benzoate administered 

 within 2 weeks were followed by lordosis in 

 response to vigorous mounting by males. 

 The behavior is described as being "at a 

 very low level" and Dr. Ball pointed out 

 that much more estrogen was required than 

 would have been necessary to produce cor- 

 responding reactions in spayed females. 

 An estimation of "how much more" can be 

 made from the work of Boling and Blandau 

 (1939) when they showed that estrous be- 

 havior was displayed by 18 of 20 female 

 rats receiving single injections of 100 R.U. 

 estradiol benzoate; 10 R.U. were sufficient 

 when supplementary progesterone was 

 given. The subcutaneous implantation of 

 from 1 to 160 diethylstilbestrol tablets 

 weighing between 50 and 1000 mg. each was 

 without apparent effect on the sexual be- 

 havior of the adult boar (Wallace, 1949). 



Nothing that is reported by Kawakami 

 and Sawyer (1959a), following the injection 

 of male rabbits with estrogen and proges- 

 terone, is inconsistent with what has been 

 found when other male mammals have been 

 given female hormones. The only observable 

 effect on two intact males was an inhibition 

 of sexual aggressiveness. One of the 2 was 

 castrated and 4 months later injected with 

 estrogen and progesterone. At this time he 

 lost interest in mounting females and the 

 electroencephalogram ( EEG) arousal thresh- 



