OPIE E L
J Exp Med. 1954 Oct 1;100(4):405-16. doi: 10.1084/jem.100.4.405.
The osmotic pressure maintained by liver tissue of the white rat preceding birth is less than that of the maternal blood serum and shortly after birth approximates this level. Following birth osmotic pressure of liver tissue, continuing to increase, reaches after about 60 to 90 days the level found in the liver of mature animals and is then isotonic with solutions of sodium chloride with concentration slightly more than twice that isotonic with blood serum. Osmotic pressure maintained by kidney tissue pursues with growth a similar course but at a lower level and about 35 to 60 days after birth reaches that found in the mature animal being represented by isotonicity with a concentration of sodium chloride slightly less than twice that isotonic with blood serum. The tissues of the whole fetus are isotonic with sodium chloride solutions less concentrated than that isotonic with the maternal blood serum.
出生前白鼠肝脏组织维持的渗透压低于母鼠血清的渗透压，出生后不久接近该水平。出生后，肝脏组织的渗透压持续升高，约60至90天后达到成熟动物肝脏中的水平，此时与浓度略高于血清等渗浓度两倍的氯化钠溶液等渗。肾脏组织维持的渗透压随生长呈现类似过程，但水平较低，出生后约35至60天达到成熟动物中的水平，表现为与浓度略低于血清等渗浓度两倍的氯化钠溶液等渗。整个胎儿的组织与浓度低于母鼠血清等渗浓度的氯化钠溶液等渗。
