670 



PHYSIOLOGY OF GONADS 



the gut, and by changing the contributions 

 of nitrogen to the metabolic pool made by 

 the body tissues. Hypothyroidism interferes 

 with the refilling of body protein stores; 

 consequently, protein needs of the repro- 

 ductive organs may not be fully met (Lea- 

 thern, 1953). It is consistent with this 

 opinion that testis recovery from protein 

 deprivation in hypothyroid rats was aided 

 by thyroxine treatment (Horn, 1955). 



Conversion of carotene to vitamin A may 

 be prevented by hypothyroidism, suggesting 

 that a subnormal amount of this vitamin 

 may contribute to fetal loss. An increased 

 intake of B vitamins might be required as 

 hypothyroidism aggravates a vitamin B12 

 deficiency, and increased intake of B vita- 

 mins enhances the capacity of young rats to 

 withstand large doses of thiouracil (Meites, 

 1953). Although a reduced metabolic rate 

 might seemingly reduce vitamin require- 

 ments, more efficient metabolic activities, 

 in the absence of hormonal stimuli, seem to 

 occur when vitamin intake is increased 

 (Meites, Feng and Wilwerth, 1957). 



Reproduction is influenced by effects 

 which are the opposite of a number of 

 those just cited, i.e., effects of malnutrition 

 on thyroid function. The need for iodine in 

 the prevention of goiter is well known. 

 However, certain foods prevent the utiliza- 

 tion of iodine in the synthesis of thyroid 

 hormone. The foods containing an anti- 

 thyroid or goitrogenic agent, as tested in 

 man, include rutabaga, cabbage, brussels 

 sprouts, cauliflower, turnip, rape, kale, and 

 to a lesser extent peach, pear, strawberry, 

 spinach, and carrot (Greer and Astwood, 

 1948). A potent goitrogen isolated from 

 rutabaga is L-5-vinyl-2-thiooxazolidine 

 ((ireer, 1950, 1956). Reduced food intake 

 will decrease the thyroid gland response to 

 goitrogens (Gomez-Mont, Paschkis and 

 Cantarow, 1947; Meites and Agrawala, 

 1949), the uptake of I^^^ (Meites, 1953), 

 and the level of thyrotrophic hormone in 

 laboratory animals (D'Angelo, 1951). The 

 thyroid changes associated with malnutri- 

 tion in man arc uncertain (Zubiran and 

 Gomez-Mont, 1953). However, a decreased 

 functioning of the gland in anorexia ner- 

 vosa, followed by an increased functioning 

 on refeeding (Poiioff, Lasche, Nodine, 



Schneeberg and \'ieillard, 1954), is sugges- 

 tive of a direct nutritional need. 



Changes in the thyrotrophic potency of 

 the rat hypophysis have been observed in 

 various vitamin deficiencies. Thiamine de- 

 ficiency may increase thyroid function, but 

 vitamin A deficiency may have the opposite 

 effect (Ershoff, 1952). The difficulties in- 

 herent in the assay of thyroid-stimulating 

 hormone (TSH) , even by current methods, 

 prevent one from drawing definite con- 

 clusions from the available data. 



Immature animals given thyroxine are 

 retarded in growth and do not survive. How- 

 ever, increasing dietary thiamine, pyridox- 

 ine, or vitamin B12 improves the ability of 

 the young rat to withstand large dosages 

 of thyroid substances (Meites, 1952), as 

 does methionine (Boldt, Harper and Elve- 

 hjem, 1958). Consideration must also be 

 given to the need for nutritional factors 

 which play a minor role in normal metabolic 

 states but increase in importance in stress. 

 Thus yeast and whole liver contain anti- 

 thyrotoxic substances (Drill, 1943; Ershoff, 

 1952; Overby, Frost and Fredrickson, 

 1959). 



Excessive thyroid hormone will prevent 

 maturation of the ovary and in adult rats 

 will cause ovarian atrophy with a cessation 

 of estrous cycles. Addition of yeast to the 

 diet permitted estrous cycles to continue 

 (Drill, 1943), but gonadal inhibition in the 

 immature animal was not ]3revented. How- 

 ever, whole liver or its w^ater-insoluble frac- 

 tion counteracted the gonadal inhibition in- 

 duced by hyperthyrodism in immature 

 rats (Ershoff, 1952). Biochemical mecha- 

 nisms by which these dietary supplements 

 can benefit rats given excessive quantities 

 of hormone are unknown. 



B. .\DREXAL GLAND, NUTRITION, AND 

 REPRODUCTION 



The problem of the relationship between 

 adrenal steroid secretions and the repro- 

 ductive system is one that still requires 

 clarification. Furthermore, the possible in- 

 fluences of nutrition can only be inferred 

 from the effects of adrenal steroids on the 

 major metabolic systems of the body. 



In the female there is a close relationshiji 

 between the adrenal and the estrous and 



