Melatonin: Translation of Ongoing Studies Into Possible Therapeutic Applications Outside Sleep Disorders.

Purpose: Melatonin, a natural hormone mainly synthesized by the pineal gland, is regulated by circadian rhythm. Synthetic melatonin is not approved by the US Food and Drug Administration for any indication. However, melatonin receptor agonists such as ramelteon and tasimelteon are US Food and Drug Administration approved and are considered by the American Academy of Family Physicians for the treatment of insomnia.

Melatonin for the Early Treatment of COVID-19: A Narrative Review of Current Evidence and Possible Efficacy.

Objective: To discuss the use of melatonin as an early treatment option on the first day of diagnosis for COVID-19.

Methods: Medical Subject Headings terms "COVID-19" and "viral diseases" were manually searched on PubMed, and relevant articles were included.

Results: The results showed that melatonin acts to reduce reactive oxygen species-mediated damage, cytokine-induced inflammation, and lymphopenia in viral diseases similar to COVID-19.

Correction: Protein fractional synthesis rates within tissues of high- and low-active mice.

[This corrects the article DOI: 10.1371/journal.pone.

Protein fractional synthesis rates within tissues of high- and low-active mice.

With the rise in physical inactivity and its related diseases, it is necessary to understand the mechanisms involved in physical activity regulation. Biological factors regulating physical activity are studied to establish a possible target for improving the physical activity level. However, little is known about the role metabolism plays in physical activity regulation.