ZINC AND REPRODUCTION - AN UPDATE

Female. Because poor maternal Zn status adversely affects pregnancy in animals, a number of investigators have tried to determine whether poor maternal Zn status in humans is related to low birthweight and complications of pregnancy. Marginal Zn status may be related to low brithweight, but there is no clearcut relation to pregnancy complications. Zn intake averages 9-10 mg/day in pregnant women, less than the RDA. Although the consensus is that serum Zn concentration is less in pregnant than non-pregnant women, there is less agreement on the extent and timing of the decrease. Poor matneral Zn status has a limited effect on placental Zn concentration but does reduce fetal Zn concentration in experimental animals. Changes in serum Zn concentration due to catabolism of maternal tissue affects teratogenicity of Zn deficiency in the rat. Appearance of Mt and Mt mRNA in rodent ovary, uterus, and placenta suggests a role for this protein in growth and differentiation. Predicting whether poor maternal Zn status might result in pregnancy complications in humans is difficult because of the differing effects of Zn deficiency on pregnancy in different species. Male. Although male reproductive organs and secretions contain high levels of Zn, fertility does not appear to be directly related to Zn concentrations. In rat and mouse testes Mt is present in cells with differentiating sperm but not mature sperm. Angiotensin-converting enzyme and testosterone are reduced in testes of Zn-deficient rats. © 1992.