BOVINE SERUM-ALBUMIN ENHANCES CALCIUM CURRENTS IN CHICKEN GRANULOSA-CELLS

The effect of bovine serum albumin (BSA) on Ca2+ currents in chicken granulosa cells was examined using both the nystatin-perforated and the conventional whole cell patch clamp techniques. Under voltage-clamp conditions, depolarizing voltage steps evoked inward Ca2+currents with both methods. The time- and voltage-dependence of Ca2+currents measured with the perforated patch technique was similar to those obtained with conventional whole cell recording. Commercially prepared BSA and essentially fatty acid free BSA both rapidly enhanced the amplitude of Ca2+ currents. However, the fatty acid free BSA was more potent, and its potency was greatly reduced by incubation with saturating concentrations of oleic acid. These data show that BSA, a common constituent of incubation media, can influence ion channels in the plasma membrane of granulosa cells.