The movement of an egg through the fallopian tube involves prostaglandins and calcium.

“How energetically demanding is that? We learned last week in talking with Paul that the ATP requirement for those sperm to travel all that distance is unbelievable. Uh what how passive versus active is the movement of that egg? How metabolically demanding is it? I don't know that we understand it completely, but you would imagine that their energy is required for for that uh to happen.”