[Studies on endocrine and spermiogenic testis function. III. Relationships between the quality of dietary proteins, testosterone content of the testes and cell nucleus volume of the Leydig cells during postnatal developme-t of rats].

Male Wistar rats, aged 15 days, received different qualities of feed proteins through 80 days (absorbable crude protein-rRP = ten per cent). For experimentation, the animals were subdivded into four groups. The first group was given casein plus four per cent methionine (K), the second maize gluten with amino acid added (M + As), the third maize gluten only (M), and the fourth casein plus four per cent methionine mixed one to three with gelatin (K/G). Live weight increases after ten days of feeding were 34+/-13.9 g (K), 24+/-8.5 g (M + As), 8+/-5.7 g (M), and 0+/-3.6 g (K/G). The same trend was recorded from testicular weight which was measured as well in ten-day intervals. The eight cyclic phases of the germinal epithelium were completely developed as of the 45th day of age in animals on K and M+/-As rations and as rations and as the 95th day of age in animals on K/G ration (followed improvement to 2:3). Spermatide transformation still was a bit differentiated by histological examination of animals on M diet on the 95th day of experimentation. The testosterone levels in testicular tissue were about 220 ng/100 g live weight after 80 days of K or M + As diets, but only 100 ng/100 g live weight after K/G or M feeding. The nuclear volumes of the interstitial cells of Leydig exhibited significant variation (p less than 0.01) between the 35th and 45th days of age, but went stable to approximately 50 mum3, independent of feed protein quality, at the onset of suxual maturity, on the 95th day of age. Complete formation of all eight cyclic phases of the germinal epithelium seems to depend on limiting values relating to testosterone per gram of testis, testicular weight nuclear volume of the interstitial cells of Leydig and live weight.