Prokineticin is a secreted protein that potently contracts gastrointestinal smooth muscle.

[2] Recently, prokineticins have been recognized in humans and other vertebrates.

[3] They are thought to be involved in several important physiological processes like neurogenesis, tissue development, angiogenesis, and nociception.

[3][4] Other important physiological roles the Bv8/Prokineticins (PKs) are involved in may include cancer, reproduction, and regulating physiological functions that influence circadian rhythms like hormone secretion, ingestive behaviors, and the sleep/wake cycle.

[5] Mutations in the PROK2 (also known as KAL4) gene have been implicated in hypogonadotropic hypogonadism and gynecomastia.