MAMMALIAN TESTIS 



337 



Ncitlier FSH nor LH hastens the appear- 

 ance of sperm in the testis of immature ani- 

 mals. No type of gonadotrophin has induced 

 the appearance of sperm in the rat earlier 

 that 35 days of age. 



Because interest in the chemical fraction- 

 ation of animal i^ituitary tissue waned after 

 1945, new studies on the effects of pituitary 

 gonadotrophins on the testis have not been 

 performed. Instead, HCG has received at- 

 tention. The well known hyperemia induced 

 in the ovary by HCG, which is used as a 

 pregnancy test, has been reported to occur 

 also in the testis by Hartman, Millman and 

 Stavorski (1950). Hinglais and Hinglais 

 (1951 ) have not confirmed this. HCG causes 

 increased testicular weight in young rats 

 (Rubinstein and Abarbanel, 1939). The ef- 

 fect of HCG on the rat testis has been sum- 

 marized by Gaarenstroom (1941), who 

 listed the following four main actions: (1) 

 stimulation of the Leydig cells in both nor- 

 mal and hypophysectomized animals to 

 produce androgen; (2) increase in growth 

 of the testis in the normal immature ani- 

 mal; (3) maintenance of testicular tubules 

 in hypophysectomized animals; (4) poten- 

 tiation of the effects of i^ituitary gonado- 

 troi)hins in either normal or hypophysecto- 

 mized animals. All effects are interpreted as 

 being caused by the increased liberation of 

 androgen. This explanation probably also 

 holds for the increased fibrosis in and 

 around the tubular wall in hypophysecto- 

 mized rats after administration of HCG, for 

 the increase in the number of primary 

 spermatocytes (Muschke, 1953; Tonutti, 

 1954), and for the slight increase in tes- 

 ticular weight (Diczfalusy, Holmgren and 

 Westerman, 1950). 



The effects of HCG in normal men are 

 similar to those in animals (Maddock, Ep- 

 stein and Nelson, 1952; Maddock and Nel- 

 son, 1952; Weller, 1954). The Leydig cells 

 become hyperplastic and produce more es- 

 trogen and androgen. This is reflected first 

 by an increase in urinary estrogen of some 

 5- to 20- fold and later by an increase in 

 17-ketosteroids of about 2-fold. The in- 

 creased secretion of steroids by the Leydig 

 cells is accompanied by an increase in the 

 frequency of erections and occasionally by 

 gynecomastia. The increased levels of es- 

 trogen and androgen induce tubular atro- 



phy. The tubular diameter becomes smaller, 

 spermatogenesis ceases, and there is an in- 

 crease in necrosis and sloughing of the 

 germinal cells. The basement membranes 

 become hyalinized, and peritubular fibrosis 

 develops. In certain eunuchoidal persons 

 ( hy{)ogonadotrophic hypogonadism ) , use of 

 HCG induces differentiation of the Leydig 

 cells and hastens maturation of the Sertoli 

 cells. Some spermatogenesis is obtained 

 (Heller and Nelson, 1947, 1948; Maddock, 

 Epstein and Nelson, 1952). If FSH also is 

 administered to such eunuchoidal men, com- 

 plete spermatogenesis occurs (Heller and 

 Nelson, 1947). 



PMS acts on the rat testis in a manner 

 intermediate between that of HCG and FSH 

 (Creep, 1937; Kemp, Pedersen-Bjergaard 

 and Madsen, 1943). Tubular growth and 

 hyperplasia of the Leydig cells result. In- 

 terstitial cell hyperi)lasia also occurs in mice 

 (Bishop and Leathern, 1946, 1948) , although 

 the testicular weight does not increase after 

 the use of PMS, as it does in rats. In the 

 opossum, PMS does not induce secretion of 

 androgen until the the animals are 70 days 

 of age (Moore and Morgan, 1943). PMS is 

 able to maintain the monkey testis after 

 hypoi)hysectomy l)ut only for 20 days, after 

 which involution occurs. If given to a hy- 

 pophysectomized monkey in which testicu- 

 lar atrophy already is present, PMS causes 

 formation of spermatocytes, but it does not 

 induce the formation of spermatids or sperm 

 cells (Smith, 1942). In man, PMS causes an 

 increase in testicular weight (Hemphill and 

 Reiss, 1945). 



Unfractionated extracts of pituitaries of 

 sheep or horses induce both tubular matura- 

 tion and androgenic formation (Sotiriadou, 

 1941 ) . Preparations of FSH in mice produce 

 slightly heavier testes but do not cause 

 androgenic secretion (Moon and Li, 1952). 

 Purified preparations of LH produce atro- 

 phy of the tubules and stimulation of the 

 Leydig cells in infantile rats, and main- 

 tenance of germinal epithelium and Leydig 

 cells in hypophysectomized rats (Zahler, 

 1950). 



XIII. Effects of Steroids on the Testis 



Between 1930 and 1940, rapid advances 

 were made in the understanding of pituitarv 

 and gonadal interrelationships, and the eon- 



