"Dr Gary Schubach conducted a clinical experiment in the mid-90s in which he collected urine from seven female ejaculators before they were aroused, then compared that to the fluid they ejaculated during orgasm."
"He found that, though the women had drained their bladders, most of the expelled fluid came from the walls of the bladder and the kidneys. The women produced between 50 and 900ml, and it was determined that the liquid was an altered type of urine with a reduced concentration of urea and creatinine.
Other researchers believe that a couple of teaspoons of fluid may be expelled by the urethal sponge or "female prostate", and that only this should be considered female ejaculate. No one has determined its biological function, although there is speculation that, since the vaginal environment is acidic in order to kill off unwanted bacteria, and male sperm is accompanied by an alkaline fluid to protect it during its journey up the vaginal canal, the alkaline female ejaculate may also have a protective function."