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OXYGEN‐HAEMOGLOBIN DISSOCIATION CURVE IN HYPOXIC RATS OF FIRST OR SECOND GENERATION
Author(s) -
Quatrini U.,
Licciardi A.,
Morici G.
Publication year - 1993
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1993.tb01680.x
Subject(s) - p50 , oxygen–haemoglobin dissociation curve , chemistry , oxygen , medicine , hemoglobin , endocrinology , diphosphoglycerate , pco2 , bohr effect , zoology , biochemistry , biology , gene , organic chemistry , transcription factor
SUMMARY 1. Albino Wistar rats were raised in a normobaric hypoxic environment (10% O 2 in N 2 ). Two generations of hypoxic rats were observed for changes in their haemoglobin‐oxygen (Hb‐O 2 ) dissociation curves (ODC), 2,3‐diphosphoglycerate (2,3‐DPG), haemoglobin (Hb), and Hill coefficients at P 50 ( n 50 ). The first generation were called (H1) and the second generation (H2). The control group (N) had a normoxic environment. 2. Thirty‐five rats (13 N rats, 12 H1 rats and 10 H2 rats) were used. The 2,3‐DPG was significantly higher in both hypoxic groups when compared with N rats (2.02 ± 0.51 mmol/L) but 2,3‐DPG of H2 rats was significantly lower than that of H1 rats (H1 = 3.48±0.58 mmol/L and H2 = 2.76±0.54 mmol/L). The haemoglobin values were N = 2.00±0.26, H1 = 2.65±0.32and H2 = 2.36±0.30 mmol/L, respectively. 3. We observed considerable differences in Hb‐O 2 affinity between the three groups of rats. In standard conditions (pH = 7.400; pCO 2 = 40 mmHg at 37°C) the H1 rats showed a significantly decreased Hb‐O 2 affinity (P 50, st = 37.0 ± 1.3 mmHg) when compared with both H2 and N rats; the H2 rats showed a significantly increased Hb‐02 affinity (P 50, st 1 31.1 ± 1.5 mmHg) when compared with controls N (P 50, st = 34.7±2.1 mmHg). There were no significant differences in n 50 values: N = 2.88 ± 0.44; H1 = 2.88 ± 0.77; and H2 = 2.94 ± 0.67. 4. Therefore, the H1 rats’ ODC was located well to the right of that of N rats; and the H2 rats had an ODC located to the left when compared with both HI and N rats. It is likely that in H2 rats the adaptive processes to the new environment are more advanced; therefore, the magnitude of the compensatory mechanisms required to maintain a sufficient tissue oxygenation may be reduced.