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Increased cardiovascular beta-adrenoceptor responsiveness in underweight subjects
Human Nutrition. Clinical Nutrition
|July 1, 1985
Summary
Underweight individuals exhibit enhanced beta-adrenoceptor responsiveness, showing greater cardiovascular reactions to Isoproterenol compared to normal weight subjects. This suggests a potential generalized increase in beta-adrenoceptor sensitivity in leaner individuals.
Area of Science:
- Cardiovascular Physiology
- Adrenergic Receptor Function
Background:
- Beta-adrenoceptor function is crucial for cardiovascular regulation.
- Body weight and composition can influence physiological responses.
- Understanding beta-adrenoceptor responsiveness in different weight categories is important for metabolic and cardiovascular health.
Purpose of the Study:
- To compare cardiovascular responses to Isoproterenol in normal weight versus underweight healthy males.
- To investigate potential differences in beta-adrenoceptor sensitivity based on body mass index (BMI).
Main Methods:
- Administered increasing bolus doses of the beta-agonist Isoproterenol to 11 normal weight and 9 underweight healthy males.
- Monitored cardiovascular responses including heart rate and blood pressure.
- Assessed cardiovascular responses to head-up tilt.
Main Results:
- Underweight subjects showed a significantly greater positive chronotropic response (heart rate increase) to Isoproterenol.
- Underweight subjects experienced a significantly greater fall in diastolic blood pressure during Isoproterenol administration.
- Cardiovascular responses to head-up tilt were similar between underweight and normal weight groups.
Conclusions:
- Lean, underweight individuals may possess enhanced beta-adrenoceptor responsiveness.
- This heightened sensitivity could be a generalized phenomenon in this population.
- Further research is warranted to explore the implications of altered beta-adrenoceptor function in underweight states.