[208 



HORMONAL REGULATION 



That more is involved may be indicated 

 by scattered observations on the rat and 

 guinea pig. Male rats with inadequate penile 

 development are hyperactive in their dis- 

 play of the lower measures of sexual behav- 

 ior when they are in the presence of estrous 

 females (Beach and Holz, 1946). Male 

 guinea pigs also display hyperactivity, but 

 in the experiments in which this hyperactiv- 

 ity was recorded the most accurately, it 

 seems to have been an expression of the lack 

 of organization of the motor centers trace- 

 able to insufficient contact with other ani- 

 mals (Valenstein, Riss and Young, 1955) 

 rather than to any underdevelopment of 

 genital structures. The writer assumes that 

 hyperactivity of this sort is explained by the 

 inability of the animal to achieve the outlet 

 that is had when ejaculation occurs. A differ- 

 ent type of hyperactivity is displayed by 

 castrated male rats and guinea pigs (Beach, 

 1942d; Grunt, 1954). This nondirected hy- 

 perexcitability, as Grunt called it, seems to 

 be a reflection of a frustration and is re- 

 garded as an indicator of cortical activity in 

 the absence of androgenic stimulation. AVhile 

 discussing the problem with Dr. John 

 Money, the suggestion was made that the 

 effect of the gonadal hormones on central 

 nervous tissue could be in the nature of a 

 coordinating or integrating action rather 

 than a matter of excitation. Such a hypothe- 

 sis is consistent with the display of the non- 

 directed hyperexcitability described by 

 Grunt. However, it may not be applicable 

 to the female, the effect of ovarian hormones 

 on the tissues mediating lordosis may be of 

 another order. 



Nissen (1929), Lehrman (1956), and 

 Rosenblatt and Aronson (1958a) have con- 

 tributed to the raw material to be examined 

 in considering the subject. All stress the role 

 of peripheral structures, but see the chapter 

 by Lehrman for a full discussion of the prob- 

 lem. Nissen, in an article containing a point 

 of view which still finds expression, postu- 

 lated that some organ other than the gonads, 

 but in functional dependence on them, ef- 

 fects a tumescence or tension in itself or in 

 another tissue or organ. This tension ini- 

 tiates afferent impulses which stimulate sex 

 activity. In the male the penis or prostate 

 was thought of as the hormone-dependent 



organ or "interpolated structure"; in the fe- 

 male, sensory impulses initiating sexual be- 

 havior were believed to be initiated in their 

 turn by tension in the uterine or vaginal tis- 

 sues. 



Lehrman in his more recent discussion of 

 the subject emphasizes that any conclusion 

 that behavior patterns are organized and 

 originate in neural centers is based on a 

 priori statements and has yet to be demon- 

 strated. Writing out of a background of ob- 

 servations on maternal behavior, he added 

 that patterns of this behavior reflect rela- 

 tionships between the center and the periph- 

 ery which have not been sufficiently consid- 

 ered. The criticism is directed to the view 

 that hormones act on central nervous mecha- 

 nisms specific for the behavior pattern con- 

 cerned (Lashley, 1938; Tinbergen, 1951) to 

 the exclusion of peripheral receptors. Or, it 

 may have been stimulated by the emphasis 

 Beach (1942e) placed on the action of gon- 

 adal hormones in increasing the excitability 

 of the c.e.m. and in lowering the threshold 

 of motor circuits without mentioning their 

 possible action on receptors as he has done 

 elsewhere (Beach and Levinson, 1950). As 

 matters stand, judgement with respect to 

 Lehrman 's criticism must be withheld. His 

 suggestion is consistent with the clinical 

 opinion that the effect of androgens in in- 

 ci'easing libido in women may be ascribed to 

 local changes in the external genitalia (Car- 

 ter, Cohen and Shorr, 1947). Support would 

 also seem to come from an experimental 

 study containing evidence (1) that there is 

 an increased olfactory sensitivity in women 

 after puberty or following the administra- 

 tion of estrogens, and (2) that in male rats 

 olfactory sensitivity is decreased by castra- 

 tion (Le Magnen, 1952a, b, 1953). Tempo- 

 rarily at least, the case is weakened by the 

 failure of Carr and Pender (personal com- 

 munication) to find that gonadal secretions 

 have a measurable effect on the absolute ol- 

 factory threshold of male rats for urine from 

 estrous females. 



Soulairac (1952a-e) has advanced a hy- 

 pothesis which must also be considered in 

 any discussion of the mechanism of hor- 

 monal action. According to him, the number 

 of ejaculations decreased following treat- 

 ment of the rat with testosterone propionate, 



