Suzuki K, Hirose H, Hokao R, Takemura N, Motoyoshi S
Department of Veterinary Internal Medicine, Nippon Veterinary and Animal Science University, Tokyo, Japan.
J Vet Med Sci. 1993 Aug;55(4):561-64. doi: 10.1292/jvms.55.561.
It is known that blood and plasma volume increase during lactation. The present paper examines whether an increase in plasma volume is accompanied by the change in plasma composition or attributed to hydro-dilution. Six dam-nursed pups and six dam-removed pups housed individually were designated as lactating rats and control rats, respectively. The plasma osmotic pressure and hematocrit value (Ht) were measured in the rats on days 3, 5, 7, 10, 13 and 18 of lactation. The total plasma protein (TP) and serum sodium concentration were also measured as they are factors affecting the plasma osmotic pressure. In addition, milk yield was estimated by the Morag technique. On day 5 and after day 10, the osmotic pressure of the lactating rats was found to be significantly lower than that of the control rats. The serum sodium concentration (days 5 and after day 10) and Tp values (days 3, 10 and 18) of the lactating rats were significantly lower than those of the control rats. Except on day 5, the Ht values of the lactating rats were significantly lower than those of the controls. During the period between days 3 and 10, milk yield was increased and it become steady (18 g/12 hr) on days 10 and 18. On and after day 10 when rats secreted a large amount of milk, it is considered that a decrease in the plasma osmotic pressure was mainly attributed to the reduction of sodium concentration by hydro-dilution. The Ht values indicate that an increase in blood volume is mainly through plasma volume rather than blood cell volume in lactating rats.
众所周知，哺乳期血容量和血浆容量会增加。本文研究血浆容量的增加是伴随着血浆成分的变化还是归因于水稀释作用。分别将六只由母鼠哺乳的幼鼠和六只与母鼠分开单独饲养的幼鼠指定为哺乳大鼠和对照大鼠。在哺乳期第3、5、7、10、13和18天测量大鼠的血浆渗透压和血细胞比容值（Ht）。还测量了总血浆蛋白（TP）和血清钠浓度，因为它们是影响血浆渗透压的因素。此外，采用莫拉格技术估算产奶量。在第5天及10天后，发现哺乳大鼠的渗透压显著低于对照大鼠。哺乳大鼠的血清钠浓度（第5天及10天后）和TP值（第3、10和18天）显著低于对照大鼠。除第5天外，哺乳大鼠的Ht值显著低于对照组。在第3天至10天期间，产奶量增加，并在第10天和18天稳定在（18 g/12小时）。在第10天及之后大鼠分泌大量乳汁时，认为血浆渗透压降低主要归因于水稀释导致的钠浓度降低。Ht值表明，哺乳大鼠血容量的增加主要是通过血浆容量而非血细胞容量实现的。
