“hypocretin-1” and “hypocretin-2” were found only in the hypothalamus .The hypothalamus, a region localized deep in the base of the brain, regulates many basic functions such as the release of hormones, blood pressure, sex, food intake regulation and sleep.
Hypocretin-1 (but not 2) can be measured in the cerebrospinal fluid (CSF) but not in the blood or in any other peripheral tissue. A lumbar puncture is required to collect CSF. Most patients with narcolepsy-cataplexy have no hypocretin-1 molecules in their CSF. Unfortunately, this testing is not commercially available