PERMEABILITY OF THE SYRIAN HAMSTER PLACENTA TO MANGANOUS IONS DURING EARLY EMBRYOGENESIS
| Autor: | Vergil H. Ferm, David P. Hanlon, Thomas F. Gale |
|---|---|
| Rok vydání: | 1975 |
| Předmět: |
Embryology
medicine.medical_specialty Placenta Hamster chemistry.chemical_element Gestational Age Growth Calcium Permeability Intestinal absorption Endocrinology Pregnancy Cricetinae Internal medicine medicine Animals Manganese Poisoning Maternal-Fetal Exchange Manganese Obstetrics and Gynecology Embryo Cell Biology Anatomy Embryo Mammalian medicine.anatomical_structure Reproductive Medicine chemistry Toxicity Gestation Female |
| Zdroj: | Reproduction. 44:109-112 |
| ISSN: | 1741-7899 1470-1626 |
| Popis: | Manganese is an essential trace element in the living system. It is invariably present in its ionic form and is known to participate in a number of biological systems (Cotzias, 1958). Relatively high levels of manganese are required to manifest toxicity. Rats fed massive doses of manganese (1\m=.\73%of the dry diet) show decreased intestinal absorption of calcium and phosphorus (Chornock, Gerrant & Dutcher, 1942). Lambs on a high manganese diet had low liver iron levels and reduced haemoglobin formation (Hartman, Matrone & Wise, 1955). Chronic manganese poisoning, characterized by neurological and psychiatric disorders, is seen among workers handling manganese ores and apparently results from inhalation of manganese oxide dusts (von Oettingen, 1935). Deficiency of the element in animals causes growth retardation, bone abnormalities, degenerative changes in the central nervous and reproductive failure (Cotzias, 1958). A specific example of its importance for the developing embryo is the occurrence of ataxia in the offspring of Mn++-deficient rats (Hurley, Everson & Geiger, 1958). Mutant mice possessing the pallid gene also manifest ataxia which Erway, Hurley & Fraser (1966) found to result from partial or complete absence of otoliths in the inner ear. Hurley and her co\x=req-\ workers showed that a single supplement of Mn++, given specifically on the 14th day of gestation, completely and permanently remedied this condition. Pallid mice also respond to Mn++ supplements but once the critical point in gestation is past the defect cannot be corrected in mutant mice or in the phenocopy rats. These findings strongly suggest that Mn+ + crosses the rodent placental barrier during gestation but so far its passage has not been demonstrated. In this report, we show that the Syrian hamster placenta is permeable to 54Mn++ during the critical stages of organogenesis and have correlated this with our earlier studies of placental transport of metal ions. Timed matings of virgin female hamsters were obtained as described by Ferm (1967). Sufficient carrier-free 54MnCl2 (New England Co.) was added to 2-50 niM-MnCl in demineralized-distilled water to give a solution containing 12-0 /iCi/ml. On Day 8 of gestation, twelve hamsters received an injection into the sublingual vein of 54Mn+ + in doses of 0-5 ml/100 g body weight. On Days 9 and 12 of gestation, six females were killed by chloroform anaesthesia. At |
| Databáze: | OpenAIRE |
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