Epidermal growth factor elevates intracellular pH in chicken granulosa cells

Area of Science:

• Cellular Physiology
• Molecular Biology
• Reproductive Biology

Background:

• Bioregulators like epidermal growth factor (EGF) often trigger intracellular alkalinization via Na+/H+ antiporter activation.
• Understanding cellular signaling in avian reproduction is vital for poultry science and egg production.

Purpose of the Study:

• To investigate the effect of epidermal growth factor (EGF) on intracellular pH (pHi) in chicken granulosa cells.
• To elucidate the role of the Na+/H+ antiporter in EGF-mediated signaling pathways in avian granulosa cells.

Main Methods:

• Intracellular pH (pHi) measurement in chicken granulosa cells using spectrofluorometry with BCECF dye.
• Exposure to varying concentrations of EGF (5-100 ng/ml) and assessment of pHi changes.
• Evaluation of Na+ dependency and inhibition by amiloride analogs to confirm Na+/H+ antiporter involvement.

Main Results:

• Resting pHi in chicken granulosa cells was determined to be 6.81.
• EGF induced a dose-dependent increase in pHi, with maximum alkalinization of 0.217 pH units at 100 ng/ml.
• The EGF-induced alkalinization was dependent on extracellular sodium and inhibited by Na+/H+ antiporter blockers.

Conclusions:

• Epidermal growth factor (EGF) activates the Na+/H+ antiporter in chicken granulosa cells, leading to intracellular alkalinization.
• This EGF-induced pHi change is a sodium-dependent process and is inhibited by specific antiporter inhibitors.
• Intracellular alkalinization via Na+/H+ antiporter activation is suggested as a component of EGF's transmembrane signaling pathway in chicken granulosa cells.