Figure 1.

Time courses of intracellular Ca²⁺ concentrations in human spermatozoa stimulated with different agonists. (A and B) Human sperm suspensions were loaded with fluo-3/AM and stimulated with 1 μM concentrations of PGE₁ and progesterone as indicated. (C) Recordings of intracellular Ca²⁺ concentrations after stimulation with 1 μM PGE₁ (1) or 1 μM progesterone (2) were superimposed. Trace 3 was obtained by simultaneous application of both agonists. The dotted lined represents a calculated addition of increases in [Ca²⁺]_i over basal values elicited by PGE₁ and progesterone in (1) and (2), respectively. One representative experiment of five is shown. (D) Capacitated human sperm loaded with fura-2/AM were immobilized on poly(l-lysine)-coated coverslips and stimulated with PGE₁ (1 μM) and progesterone (1 μM) as indicated. Fluorescence ratios (F₃₄₀/F₃₈₀) obtained from measurements of 10 single sperm were calculated after subtraction of autofluorescence. One representative experiment of three is depicted.