Reproductive system development, vitamin

Effects of thyroid hormone The organ level actions of the thyroid drugs include normal growth and development of the nervous, skeletal, and reproductive systems and control of metabolism of fats, carbohydrates, proteins, and vitamins. The results of excess thyroid activity (thyrotoxicosis) and hypothyroidism (myxedema) are summarized in Table 38-1. 

The reproductive system requires a vitamin A-active substance for maintaining a normally differentiated epithelium, for other functions supportive of spermatogenesis in males (Palludan, 1966 Ahluwalia and Bieri, 1971 Thompson et al, 1964 Coward et al, 1969 Mitranond et al, 1979 Sobhon et al, 1979), and of a full gestation, embryonic development, and delivery in females (Thompson et al, 1964 Takahashi et al, 1975) it is also required for hatch-ability of the fertile eggs of fowl (Thompson et al, 1969). Retinoic acid can fulfill the role of epithelial maintenance, but retinol is required for the other functions noted. An exception appears to occur in the cockerel, in which retinoic acid is reported to maintain spermatogenesis (Thompson et al, 1969). 

Vitamin A is a necessary micronutrient in the diet for vision, growth, tissue differentiation, reproduction, and maintenance of the immune system. A deficiency of vitamin A affects reproduction in both male and female experimental animals. In the male, retinol is required for normal spermatogenesis in the female, the vitamin is necessary for both conception and normal development of the fetus. 

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