Hormone That Regulates Sleep
This page is the CodyCross answer for the clue below from Inventions, Group 57, Puzzle 4.
Question
Hormone That Regulates Sleep
Answer
MELATONIN
Word Meaning:
MELATONIN — A hormone, related to serotonin, that is secreted by the pineal gland, and stimulates colour change in the skin of reptiles, and is involved in the sleep and wake and reproductive cycles in mammals.
Definitions from Wiktionary.