REPRODUCTIVE ENDOCRINOLOGY IN BIRDS 



1125 



ment of the tubular glands and the smaller 

 amount of albumen secreted. Oviducts were 

 still larger than those of birds treated with 

 estrogen only. However, this inhibitory ef- 

 fect of the higher dose of testosterone is 

 surprising in view of the oviduct stimula- 

 tion obtained with even higher doses (per 

 unit of body weight) of androgen in the 

 black-crowned night heron, Nycticorax nyc- 

 ticorax (Noble and Wurm, 1940) , the starl- 

 ing, Sturnus v. vulgaris (Witschi and Fugo, 

 1940) , the sparrow hawk, Falco s. sparvenus 

 (Nelson and Stabler, 1940), the house spar- 

 row, Passer domesticus (Ringoen, 1943), 

 and the fowl (Kline and Dorfman, 1951). 

 Ringoen (1943) made particular note of the 

 full development of the tubular glands of 

 the oviduct and stated that this might be 

 due to the secretion of estrogen by the ovary, 

 inasmuch as large follicles had developed 

 under the influence of the exogenous testos- 

 terone. 



The question as to which hormones, an- 

 drogen or progesterone, synergize with estro- 

 gen to give full oviduct development in 

 birds may be answerable only if specified 

 for species, and even then the possibility 

 exists that all three hormones act together. 

 In the fowl, ovary, oviduct, and comb de- 

 velopment occur about the same time; the 

 comb growth is evidence that androgen is 

 secreted in considerable quantities. Simi- 

 larly, female starlings secrete large amounts 

 of androgen which stimulate the vasa def- 

 erentia and cause the yellow coloring of the 

 bill (Witschi and Fugo, 1940). Lehrman 

 and Brody (1957) proposed that progester- 

 one, which acts synergistically with estrogen 

 to cause oviduct development of ringdoves 

 {Streptopelia risoria) , may be the hormone 

 which is secreted and is responsible for 

 the synergism. This hypothesis was sug- 

 gested by the onset of incubation behav- 

 ior after progesterone administration (Lehr- 

 man, 1958). In this case, progesterone might 

 stimulate the physiologic development of 

 the oviduct and simultaneously induce pa- 

 rental behavior. In none of the birds in- 

 vestigated is there any evidence against an 

 hypothesis which assumes that estrogen 

 interacts with both, androgens and pro- 

 gesterone, to stimulate the oviduct. 



Nalbandov ( 1959a » presented evidence 



that carbonic anhydrase activity in the 

 shell gland of the fowl may involve the 

 I)ituitary, but the manner in which the 

 pituitary is involved awaits clarification. 



A brief summary of various other factors 

 involved in the normal development of the 

 oviduct and in the response of the oviduct 

 to exogenous gonadal hormones concludes 

 the discussion of the oviduct. 



1. Campos and Shaffner (1952) demon- 

 strated that different sire and dam families 

 show differences in the magnitude of re- 

 sponse of the oviduct to a standard dose of 

 estrogen and androgen. 



2. The exposure to infectious bronchitis 

 when the birds are 1 to 14 days old causes 

 development of incomplete oviducts in 

 which a great decrease in size occurs in 

 the magnum and shell gland (Broadfoot, 

 Pomeroy and Smith, 1956). The older the 

 birds at the time of exposure, the less was 

 the incidence of incomplete oviducts. 



3. The presence of a well developed right 

 oviduct, induced by estrogen treatment of 

 the embryo, was highly correlated with a 

 decrease in length of the left oviduct in 

 sexually mature hens. The hypothesis pro- 

 posed to explain this phenomenon was that 

 not enough estrogen is secreted by the ovary 

 of the adult hen to stimulate both oviducts 

 (van Tienhoven, 1957) . It may explain also 

 the presence of two completely developed 

 oviducts in certain inbred lines (Morgan 

 and Kohlmeyer, 1957). If the presence of 

 the right oviducts were the result of larger 

 than normal amounts of estrogen deposited 

 in the yolk, one might expect larger than 

 normal estrogen secretion by the hens of 

 these strains, so that sufficient estrogen 

 would be present to stimulate both oviducts. 



4. It lias been established that nutritional 

 deficiencies can affect the response of the 

 oviduct to exogenous estrogens. From these 

 investigations it seems that a paradoxical 

 situation exists in that certain deficiencies 

 such as the thiamine (Kline and Dorfman, 

 1951), nicotinic acid (Haque, Lillie, Shaff- 

 ner and Briggs, 1949; Kline and Dorfman, 

 1951), riboflavin, pantothenic acid, choline, 

 and vitamin D deficiency (Haque, Lillie, 

 Shaffner and Briggs, 1949) result in a 

 greater than normal response, whereas folic 

 acid deficiency (Hertz and Sebrell, 1944; 



