Accumulation of Manganese and the Sexual Cycle in Ostrea virginica

Abstract

S INCE the finding of manganese in blood, urine, teeth, gallstones, milk, and many internal organs of man (Bertrand et Medigreceanu, i912a, i912b, 1912c) the question whether its presence in animal tissues is accidental or whether this metal is an indispensable constituent of the normal organism has been debated in the scientific literature. Inasmuch as a comprehensive review of the subject has been made by Browning (i937), it will suffice to mention here only a few papers which deal with the role of Mn in the reproductive cycle and growth of animals. Kemmerer, Elvehjem, and Hart (1931) found that the addition of Mn to the food of mice increases the rate of their growth, and they attributed this effect to the stimulation of ovarian and testicular functions. According to Orent and McCollum (i93i), Mn is essential in maintaining the normal development of embryonic and young tissues and in the production of a hormone, probably from the anterior lobe of the hypophysis, which is essential for the functioning of the testes and for the proper development and functioning of the mammary tissue. Of special interest are their observations that an Mn-free diet results in the degeneration of testes in the male rats, which otherwise develop normally, and leads to the loss of the maternal instincts in the females.