Table 1: Factors known to display circadian fluctuations have a role in OL maturation as well as myelination, another link?

The timing of sleep and arousal is controlled by the circadian timing system with a central clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN synchronizes independent circadian clocks located in each organ of the body to generate tissue specific rhythms. Light entrains the master pacemaker in the SCN, which in turn synchronizes extra-SCN central (brain) and peripheral clocks. Brain clock outputs include behavioural rhythms (i.e., sleep, feeding), while peripheral clock outputs include metabolic rhythms (i.e., glucose and lipid homeostasis). Among the rhythmically regulated SCN outputs important for oligodendrocytes are melatonin, glucocorticoids, arousal circuits mediated by NE and ACH.

Additional factors and supporting evidence, not an exhaustive list
Insulin	Roth et al. (1985) J Neurol Sci 71(2–3):339–50 Haroutunian et al (2014) Glia 2014 62(11):1856–77 Chirivella et al. (2017) Stem Cells 35(12):2403–2416
Glucocorticoids	Chetty et al. (2014) Mol Psychiatry 19(12):1275–1283 Hinds et al. (2017) PLoS One 12(4):e0175075
Thyroid hormone	Almazan et al. (1985) Dev Neurosci 7(l):45–54. Lee & Petratos (2016) Mol Neurobiol 53(9):6568–6583 Zhang et al. (2016) Mol Neurobiol 53(7):4406–16
Melatonin	Wen et al. (2016) J Neuroimmune Pharmacol. ll(4):763–773 Ghareghani et al. (2017) Cell Mol Neurobiol. 37(7):1319–1324
BDNF	Miyamoto et al. (2015) J Neurosci 35(41): 14002–8 Peckham et al. (2016) Glia 64(2):255–69
Norepinephrine	Ghiani CAetal. (1999) Development 126(5):1077–90 Ghiani & Gallo (2001) J Neurosci 21(4):1274–82 Marinelli et al. (2016) Front Cell Neurosci. 10:27
Acetylcholine	Cohen et al. (1996) Brain Res Mol Brain Res 43,193–201 Zhou et al. (2004) Cell Biol Int 28:63–67 De Angelis et al. (2012) Dev Neurobiol 72(5):713–28 Imamura et al. (2015) J Neurochem. 135,1086–1098 Marinelli et al. (2016) Front Cell Neurosci. 10:27 Fields et al. (2017) Glia 65(5):687–698
Histamine	Chen et al. (2017) PLoS One 12(12):e0189380 Schwartzbach et al. (2017) J Neurol 264(2):304–315
Glutamate	Gallo et al. (1996) J Neurosci 16(8):2659–70 Gallo & Ghiani (2000) Trends Pharmacol Sci 21(7):252–8 Fannon et al. (2015) Glia 63(6):1021–35
GABA	Yuan et al. (1998) Development 125(15):2901–14 Luyt et al. (2007) J Neurochem 100(3):822–40 Hamilton et al. (2017) Glia 65(2):309–321.