PHYSIOLOGY OF ANTERIOR HYPOPHYSIS 



253 



assays for diagnostic purposes, especially 

 for the early diagnosis of pregnancy. A 

 number of species of frogs and toads are 

 in use, mainly: (1) the male leopard frog, 

 Ra7m pi-piens (Wiltberger and Miller, 1948; 

 Robbins and Parker, 1949; Haskins and 

 Sherman, 1952) ; positive tests are also ob- 

 tained with hypophysectomized frogs (Kis- 

 sen, 1954), (2) the female Xenopus laevis 

 (Thorborg and Hansen, 1951 ; Hobson, 

 1952) , and (3) the male toad, Bufo arenanim 

 (Hansel) (Galli Mainini, 1948; Allison, 

 1954; for review, see Houssay, 1954). The 

 Galli Mainini test is held to be relatively 

 more specific for the chorionic gonadotrophin 

 in that positive responses are not obtained 

 with urine from normal men or nonpregnant 

 women, regardless of the presence or ab- 

 sence of functioning gonads. This is in line 

 with Atz and Pickford's finding that sper- 

 miation is mainly a function of LH, the 

 urinary output of which in normal men is 

 very low. 



4. Reptiles 



Few observations have been made on the 

 interrelations of the pituitary and gonads 

 in reptiles (Kehl and Combescot, 1955) and 

 fewer still on the responsiveness of reptiles 

 to heterozoic gonadotrophins. In viviparous 

 snakes hypophysectomy led to regression of 

 gonads and death of the embryos and pre- 

 mature parturition (Clausen, 1940; Brag- 

 don, 1951). Testis impairment following hy- 

 l)ophysectomy in male garter snakes was 

 corrected by daily implantation of pituitary 

 glands froni the same species (Schaefer, 

 1933). Crude extracts of sheep pituitary 

 promoted marked gonad stimulation in the 

 lizard, Uromastix (Kehl, 1944; Kehl and 

 Combescot, 1955), immature alligators, 

 Alligator jnississippiensis (Forbes, 1937), 

 and terrapins, Malaclemmys centrata (Ris- 

 ley, 1941 1 . In extended studies of the cha- 

 meleon, Anolis carolinensis, Evans (1948) 

 oljtained positive results with mammalian 

 gonadotrophins unspecified. 



5. Birds 



Among birds males of all ages and mature 

 females are responsive to gonadotrophins 

 of both avian and mammalian sources 

 (Breneman, 1936; Byerly and Burrows, 



1938; Nalbandov and Card, 1946; Das and 

 Nalbandov, 1955). These observations are 

 based mainly on the domestic breeds, such 

 as chickens, ducks, and turkeys (reviewed 

 by Nalbandov, 1953a). Evidence suggesting 

 qualitative differences between avian and 

 mammalian gonadotrophins has been ob- 

 tained by Nalbandov, Meyer and McShan 

 (1951), Das and Nalbandov (1955), and 

 Taber, Clay tor, Knight, Gambrell, Flowers 

 and Ayers (1958). Thus, the ovarian cortex 

 of the sexually immature female chicken, 

 although notably insensitive to mammalian 

 gonadotrophins, has responded to avian 

 pituitary extract. Taber and her associates 

 noted significant follicle stimulation but no 

 precocious ovulation in immature female 

 chickens receiving long-term treatment with 

 acetone-dried avian anterior lobe substance. 

 In contradistinction, the medullary portion 

 of the immature ovary, like the testes of 

 the male bird, responded with increase in 

 weight and androgen production at any age 

 and to hormones of either mammalian or 

 avian source. Following hypophysectomy of 

 prepubertal female birds, the medullary 

 area remained responsive to avian, but not 

 to mammalian, gonadotrophin. Moreover, 

 the effectiveness of mammalian gonadotro- 

 phins in maintaining the ovaries and comb 

 of hypophysectomized laying hens was of 

 short duration (Biswal and Nalbandov, 

 1952; Nalbandov, 1953a); egg-laying con- 

 tinued 5 to 7 days postoperatively, and comb 

 size was sustained for 10 to 15 days. Avian 

 hormone, alone or in combination with mam- 

 malian gonadotrophin, was effective over 

 treatment periods lasting up to 35 days. The 

 possibility that these results might have 

 been influenced by the development of im- 

 mune bodies was not eliminated. 



Observations of interest have been made 

 on the hypophyseal control of the rudi- 

 mentary right gonad in hens (Kornfeld and 

 Nalbandov, 1954). Compensatory hyper- 

 trophy of this structure, seen regularly in 

 poulards, has been completely prevented by 

 injections of estrogen, and to lesser extent 

 by androgen. Hypophysectomy, moreover, 

 causes regression of the enlarged right rudi- 

 ment which cannot be forestalled by injec- 

 tions of hog or sheep gonadotrophins, nor by 

 PMS. Whether chicken gonadotrophins 



