Oxygen binding functions of blood and hemoglobin from the Chinese pangolin, Manis pentadactyla: possible implications of burrowing and low body temperature.
We measured O2 equilibria of adult blood and of 'stripped' (cofactor-free) hemolysates from adult and newborn Manis pentadactyla, in order to assess the implications of the burrowing habit and the low deep-core temperature in pangolins, and to discern the mechanisms for maternal-fetal O2 transfer. At pH 7.4 and body temperature (33 degrees C) the blood O2 affinity was significantly higher than in similarly sized non-burrowing, 'normothermic' mammals (P50 = 21 and 33 mm Hg, respectively) indicating an adaptation to hypoxic burrow conditions. This difference is not attributable to a higher intrinsic O2 affinity in the pangolin Hb or to significant differences in its sensitivity to temperature and erythrocytic 2,3 diphosphoglycerate (DPG), but tallies with lower DPG/Hb ratios than generally found in mammals. Stripped adult and newborn hemolysates show similar O2 affinities and pH and DPG sensitivities, but reveal a specific adult Hb that develops after birth, in sharp contrast with the ontogenetic changes in other mammals where specific fetal Hbs are lost after birth.
D019794:2,3-Diphosphoglycerate; D000375:Aging; D000818:Animals; D000831:Animals, Newborn / Q000097:blood; D001831:Body Temperature; D002245:Carbon Dioxide / Q000097:blood; D004163:Diphosphoglyceric Acids / Q000097:blood; D005260:Female; D006454:Hemoglobins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008297:Male; D008431:Maternal-Fetal Exchange; D010100:Oxygen / Q000097:blood*; D011247:Pregnancy; D011485:Protein Binding; D004490:Xenarthra / Q000097:blood*
D004163:Diphosphoglyceric Acids; D006454:Hemoglobins; D019794:2,3-Diphosphoglycerate; D002245:Carbon Dioxide; D010100:Oxygen