6/ 



PHYSIOLOGY OF GONADS 



TABLE 12.5 



Effect of diet on the testes of immature rats 



(From J. H. Leathern, in Re-productive Phijsiology 



and Protein Nutrition, Rutgers University 



Press, New Brunswick, N. J., 1959.) 



Sperm 



Initial control . . . 

 20 per cent X 30 



days 



6 per cent X 30 



days 



3 per cent X 30 



days 



per cent X 30 



days 



per cent + 5 

 per cent liver. , 



per cent + 5 

 per cent yeast 



G5 per cent X 30 

 davs 







100 



50 













 



100 



2. Protein 



The minimal amount of dietary protein 

 which will support reproduction, lactation, 

 and growth is 16.7 per cent (Goettsch, 1949) . 

 Thus, it is not surprising that maturation 

 of testes and accessory sex organs was pre- 

 vented in immature rats (Horn, 1955) and 

 mice (Leathern and DeFeo, 1952) when 

 they were fed a protein-free diet for 15 to 

 30 days after weaning. Furthermore, supple- 

 ments of 5 per cent liver to the casein-free 

 diet had no effect. After a month, the testes, 

 averaging 329 mg., decreased to 140 mg. in 

 rats fed per cent casein, but the weight 

 increased to an average of 1694 mg. and 

 1747 mg. in rats fed 20 per cent and 65 per 

 cent casein, respectively (Table 12.5). Fol- 

 lowing protein depletion, there was a de- 

 crease in tubular ribonucleic acid and an in- 

 crease in lipid. Accumulation of gonadal 

 lipid in the inactive testis may be an ab- 

 normal assimilation of a degenerative na- 

 ture or simply nonutilization. A diet con- 

 taining 6 per cent casein permitted the 

 formation of spermatozoa in some animals 

 (Guilbert and Goss, 1932). When the 6 per 

 cent casein diet was fed to immature ani- 

 mals for 30 days 50 per cent of the rats 

 exhibited some spermatozoa; in addition, 

 testis weight increased slightly and seminal 



vesicle weight doubled, but body weight was 

 not improved (Horn, 1955). Thus, as we 

 noted earlier, the reproductive system may 

 gain special consideration for protein allot- 

 ments when supplies are limited. 



Gain in testis weight in immature male 

 rats and the biochemical composition of the 

 immature testis are influenced by the nutri- 

 tive value of the protein fed. The testes of 

 normal immature rats contain 85 per cent 

 water, 10.5 per cent protein, 4.5 per cent 

 lipid, and detectable glycogen (Wolf and 

 Leathern, 1955). Proteins of lower nutritive 

 value (wheat gluten, peanut flour, gela- 

 tin ) may permit some increase in testis 

 weight, but testis protein concentration de- 

 creased, percentage of water increased, and 

 lipid and glycogen remained unchanged 

 (Table 12.6). The enzyme ^fi-glucuronidase, 

 which has frequently been associated with 

 growth processes, exhibited no change in 

 concentration as the testis matured or was 

 jirevented from maturing by a protein-free 

 diet (Leathem and Fisher, 1959). Not only 

 are the weight and composition of the testis 

 influenced by feeding proteins of varied bio- 

 logic value, but the release of androgen is 

 more markedly altered. When a 22-day-old 

 male rat was fed a 20 per cent casein diet 

 for 30 days, the seminal vesicle and ventral 

 prostate weights increased 9- to 10-fold in 

 comparison with initial control weight. Sub- 



TABLE 12.6 



Niiiritioiial effects on testis-coin position 



in immature rats 



(From R. C. Wolf and J. H. Leathem, 



Endocrinology, 57, 286, 1955.) 



20 pel' cent ca- 

 sein 



20 per cent wheat 

 gluten 



20 per cent i)ea- 

 nut flour 



20 i)er cent gela- 

 tin 



5 per cent casein 



Fox chow 



Initial control . . 



72.3j30.4 

 04.634.0 



1468 

 1017 



1257 66.1 

 2101 



28.8 



0.11 

 0.18 

 0.11 

 0.10 



684,62.4 29.2 0.26 

 1515'70.3 30.3 0.15 

 273 72. 7:30. 10.19 



