CHAPTER 213 – Peptide Chronomics

Chronomics, the mapping of broad time structures (chronomes), provides the indispensable control whether studies aim at examining the effect of a given intervention such as dietary restriction, at optimizing the timing of administration of treatment, or at assessing an elevated risk of developing a disease such as cancer. An increase in circadian amplitude exceeding any effect on the mean is likely to yield controversial results from single spot checks. An analog of the adrenocorticotropic hormone (ACTH 1–17), administered in the evening may help patients with rheumatoid arthritis, but may be ineffective when given around awakening. A daytime single sample of prolactin may not be discriminatory in assessing breast cancer risk when large differences are found during the rest span. The merits of assessing peptide chronomics are perhaps best illustrated by the facts that a peptide drug may have a major effect at one circadian stage but not at another, that a major effect on a polypeptide may be exerted again at one circadian stage but not at another, and that, by the design and the software of chronomics, relatively small numbers of patients are needed to validate such effects by inferential statistics.