Embryotoxic and Teratogenic Effects of Sodium Molybdate in Rats

Éva Szakmáry1, György Ungváry2, and Veronika Morvai3

1 National Institute for Occupational Health, József Fodor National Center for Public Health, Budapest, Hungary
2 József Fodor National Center for Public Health, Budapest, Hungary
3 2nd Department of Internal Medicine, Faculty of Medicine, Semmelweis University, Budapest, Hungary

Corresponding author: Éva Szakmáry, Ph.D.
    National Institute for Occupational Health
    József Fodor National Center for Public Health
    H-1450 Budapest, Hungary
    Telephone: (+36) 1-476-1175
    Fax number: (+36) 1-215-6891
    E-mail: szakmary@fjokk.hu

CEJOEM 2004, Vol.10. No.2.: 158–169

Key words:
Embryotoxicity, internal organ retardation, body mass retardation, minor anomalies

Abstract:
The embryotoxic and teratogenic effects of sodium molybdate, administered by gavage, was studied in pregnant rats. The dams were treated daily with doses of 0, 50, 100 or 150 mg/kg of the substance dissolved in water, during the whole gestation. The animals were processed on the day 21 of gestation, using routine teratological methods. Following the last treatment, the concentration of molybdenum was determined in the maternal and fetal blood as well as in the maternal and fetal organs. On day 11 of gestation, progesterone and 17β-estradiol concentrations or secretion were determined in the groups of dams treated with the highest dose. The direct fetotoxic effect of the molybdenum salt was examined in rats treated intraamnially. The postnatal effect of 0 or 150 mg/kg doses of sodium molybdate administered prenatally was studied in the offspring during the lactation period.
    It was found, that the molybdenum salt in the doses applied did not exert a maternal toxic effect; molybdenum got to the fetal side both transplacentally and paraplacentally and could be demonstrated in the fetal blood, liver, and kidneys in significant concentrations. A daily dose of 50 mg/kg molybdenum hindered the development of the fetal body mass and skeletal system and caused retardation of the internal organs. It increased the frequency of minor anomalies of the internal organs, but did not induce major anomalies.
    Molybdenum proved to be embryotoxic and slightly teratogenic. Based on the intraamniotic examinations, it was concluded that mainly the direct cytotoxic effect of molybdenum was responsible for its embryotoxic and teratogenic effects. Molybdenum had no effect on the secretion of sexual steroids or their peripheral blood levels, playing a significant role in the development of the fetus. The prenatal molybdenum exposure did not affect the perinatal and survival indices, however, it decreased the body mass gain of the pups during the lactation.

Received: 22 June 2004
Accepted: 1 July 2004
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