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Effect of hormonal and substrate backgrounds on cell membrane function in normal males
G A Fantini1, J P Roberts, S F Lowry
1Department of Surgery, New York Hospital-Cornell Medical Center, New York 10021.
Journal of Applied Physiology (Bethesda, Md. : 1985)
|September 1, 1987
Summary
Nutrient availability and hormones like epinephrine significantly impact human skeletal muscle membrane potential. Intravenous feeding depolarized resting membrane potential, while epinephrine restored it, suggesting hormonal and substrate influences on cellular function.
Area of Science:
- Physiology
- Cellular Biology
- Endocrinology
Background:
- Cellular membrane function is crucial for skeletal muscle activity.
- In vivo regulation of membrane potential by hormonal and substrate factors is not fully understood.
Purpose of the Study:
- To investigate the effects of intravenous feeding and epinephrine on resting membrane potential (Em) in human skeletal muscle.
- To explore the role of substrate availability and hormonal background in modulating cellular membrane function.
Main Methods:
- Serial transcutaneous measurements of resting Em in anterior tibialis muscle of healthy male volunteers.
- Intravenous feeding (IVF) and epinephrine infusion were administered to different subject groups.
- Muscle biopsy and Nernst equation calculations were used to assess transmembrane electrolyte distribution.
Main Results:
- Enteral feeding and subsequent IVF led to depolarization of resting Em.
- Combined IVF and epinephrine infusion resulted in repolarization of Em to normal levels.
- Intracellular potassium concentration increased during epinephrine infusion with IVF.
Conclusions:
- Hormonal background and substrate availability significantly modulate in vivo cellular membrane function in human skeletal muscle.
- Epinephrine may facilitate sodium-dependent amino acid transport, influencing membrane potential.
- These findings highlight the dynamic regulation of skeletal muscle Em by nutritional and hormonal states.