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Thyroxine effect on 2,3-diphosphoglycerate (2,3-DPG) level in sheep erythrocytes
Acta Physiologica Polonica
|May 1, 1982
Summary
Thyroxine administration in sheep significantly increased erythrocyte 2,3-diphosphoglycerate (2,3-DPG) levels in a biphasic manner. Heart rate increased, but cardiac electrical activity remained unchanged.
Area of Science:
- Endocrinology
- Physiology
- Biochemistry
Background:
- Thyroid hormones, like thyroxine, play crucial roles in regulating metabolism and physiological processes.
- 2,3-diphosphoglycerate (2,3-DPG) is a key regulator of hemoglobin's oxygen affinity.
- Understanding the interaction between thyroxine and 2,3-DPG is important for comprehending oxygen transport dynamics.
Purpose of the Study:
- To investigate the effect of D,L-thyroxine administration on 2,3-DPG concentration in sheep erythrocytes.
- To assess the impact of thyroxine on heart rate and cardiac electrophysiological activity.
- To determine the time course and pattern of changes in 2,3-DPG levels post-thyroxine administration.
Main Methods:
- 18 adult sheep were divided into two groups: 13 received an intramuscular dose of D,L-thyroxine (100 mg), and 5 controls received normal saline.
- Blood samples were collected from the jugular vein at 4-hour intervals over 44 hours.
- Erythrocyte 2,3-DPG concentration and hemoglobin levels were measured. Rectal temperature and cardiac electrophysiological activity were also recorded.
Main Results:
- Thyroxine administration led to a biphasic increase in erythrocyte 2,3-DPG concentration, with peaks occurring at different times in faster and slower-reacting animals.
- The initial mean 2,3-DPG concentration was higher in thyroxine-treated sheep (0.57 mumol/g Hb) compared to controls (0.43 mumol/g Hb).
- Thyroxine significantly increased heart rate from a baseline of 90-99/min to a maximum of 117/min, without altering cardiac electrical activity.
Conclusions:
- D,L-thyroxine administration induces significant, biphasic alterations in erythrocyte 2,3-DPG levels in sheep.
- Thyroxine affects oxygen-carrying capacity by modulating 2,3-DPG, potentially impacting tissue oxygen delivery.
- While thyroxine influences heart rate, it does not appear to significantly affect the heart's basic electrical function in this model.