Hibernation induction trigger (hibernation inducement trigger or HIT) is a substance found in the blood of hibernating animals. If blood is taken from a hibernating squirrel in the winter and injected into another squirrel in the spring, the normally active squirrel goes into hibernation. HIT can also be found in the blood of hibernating bears. Researchers were able to prolong the life of an isolated pig's heart with HIT. This may have potentially important implications for organ transplant, as it could allow organs to survive for up to 18 or more hours, outside the human body. This would be a great improvement from the current 6 hours. NASA is co-funding research into HIT, with an eye to long-duration space travel for humans. Chemically, HIT is an opioid-like substance.
