CHEMICAL DETERMINATION OF OESTROGEN DISTRIBUTION IN THE FOETUS AND PLACENTA OF THE DOMESTIC PIG

Abstract

ABSTRACT The concentrations of oestrogens and solvolyzable oestrogen conjugates have been estimated chemically in extracts of different foetal organs and of placental tissues of the domestic pig during late stages of pregnancy. Unconjugated oestrogens were not detected (< 0.5 μg/100 g wet weight of tissues) in foetal adrenals, ovaries and testes, nor in foetal spleen. Oestrogen concentrations were low in foetal heart. Foetal placenta, maternal placenta and uterine tissues were analyzed separately. There was a higher oestrogen concentration in foetal (176.3 μg/100 g) than in maternal (74.0 μg/100 g) placenta. In placental tissues oestrogens were present mainly as unconjugated steroids while a greater proportion was found as conjugates in uterine tissues. The mean concentrations of unconjugated oestrogens and oestrogen sulphates respectively were 111.9 and 66.5 μg/100 g, for foetal placenta; 57.9 and 16.5 μg/100 g, for maternal placenta; and 3.1 and 7.1 μg/100 g, for uterine tissues. Greater oestrogen concentrations were noted in the foetal placenta and fluids from males than from females; the total oestrogen concentrations for male and female samples respectively were 235.5 and 121.2 μg/100 g, for foetal placenta; and 815.7 and 454.7 μg/100 ml, for foetal fluids. Oestrogens were present mostly as conjugates in various foetal tissues. The mean oestrogen concentrations for unconjugated and solvolyzable forms respectively were 45.2 and 80.9 μg/100 g, for liver; 26.0 and 42.4 μg/100 g, for kidneys; 14.6 and 38.5 μg/100 g, for lungs; and 10.9 and 29.4 μg/100 g, for skin. Unconjugated oestrogens predominated, however, in intestinal tissues and meconium. Mean concentrations of unconjugated and conjugated oestrogens respectively were 256.1 and 98.2 μg/100 g, for small intestine; 531.8 and 132.1 μg/100 g, for large intestine; and 2152.2 and 137.2 μg/100 g, for meconium. Oestrone was the major oestrogen found. Lesser amounts of oestradiol-17β were present.