FLUIDIZATION OF THE RAT LIVER MICROSOMAL MEMBRANE AT BIRTH

The Lipid apparent microviscosity ( η ¯ ) of the liver microsomal membrane in the one day-old rat was 56% of that observed in fetal liver on day 18 of pregnancy. The values of η ¯ in the adult rat were only slightly lower than in the newborn animal. This remarkable perinatal fluidization of the microsomal membrane was due to a 83% increase in its phospholipid to cholesterol molar ratio.