Murphy W S, Metcalfe J, Hoversland A S, Dhindsa D S
Respir Physiol. 1977 Feb;29(1):73-80. doi: 10.1016/0034-5687(77)90118-9.
The oxygen affinity of opossum blood changes in the postnatal period. The youngest opossums studied were 53 days of age (dated from the day of transit from vagina to pouch) and still confined to the maternal pouch: they had a blood P50 of 32.6 +/- 2.9 mm Hg. The blood P50 value then increased significantly, in two steps. First, while the young were still in the pouch, blood P50 rose secondary to a rise in the concentration of 2,3-diphosphoglycerate (DPG). Blood P50 and DPG concentration then remained stable until the animals left the maternal pouch, when DPG rose again, causing a further increment in the blood P50 which peaked at 48.7 +/- 4.5 mm Hg in animals 148 days old. Blood P50 subsequently decreased significantly, reaching the adult value (42.0 +/- 1.9 mm Hg) at about 250 days.
负鼠血液的氧亲和力在出生后时期会发生变化。所研究的最年幼负鼠为53日龄（从从阴道转移至育儿袋之日起算），仍局限于母兽的育儿袋中：它们的血液P50为32.6±2.9毫米汞柱。血液P50值随后分两步显著升高。首先，在幼兽仍在育儿袋中时，血液P50因2,3 - 二磷酸甘油酸（DPG）浓度升高而上升。然后血液P50和DPG浓度保持稳定，直到动物离开母兽育儿袋，此时DPG再次升高，导致血液P50进一步增加，在148日龄的动物中达到峰值48.7±4.5毫米汞柱。随后血液P50显著下降，在约250日龄时达到成年值（42.0±1.9毫米汞柱）。
