Lee, Ji Eun Zamdborg, Leonid Southey, Bruce R. Atkins, Norman, Jr. Mitchell, Jennifer W. Li, Mingxi Gillette, Martha U. Kelleher, Neil L. Sweedler, Jonathan V. 2024-01-20T13:03:11Z 2024-01-20T13:03:11Z 2021-08-31 2013-02 1535-3893 https://pubs.kist.re.kr/handle/201004/128429 In mammals the suprachiasmatic nucleus (SCN), the master circadian clock, is sensitive to light input via the optic chiasm and synchronizes many daily biological rhythms. Here we explore variations in the expression levels of neuropeptides present in the SCN of rats using a label-free quantification approach that is based on integrating peak intensities between daytime, Zeitgeber time (ZT) 6, and nighttime, ZT 18. From nine analyses comparing the levels between these two time points, 10 endogenous peptides derived from eight prohormones exhibited significant differences in their expression levels (adjusted p-value <0.05). Of these, seven peptides derived from six prohormones, including GRP, PACAP, and CART, exhibited >= 30% increases at ZT 18, and the VGRPEWWMDYQpeptide derived from proenkephalin A showed a >50% increase at nighttime. Several endogenous peptides showing statistically significant changes in this study have not been previously reported to alter their levels as a function of time of day, nor have they been implicated in prior functional SCN studies. This information on peptide expression changes serves as a resource for discovering unknown peptide regulators that affect circadian rhythms in the SCN. English AMER CHEMICAL SOC GASTRIN-RELEASING-PEPTIDE VASOACTIVE INTESTINAL POLYPEPTIDE CYTOCHROME-OXIDASE ACTIVITY CYCLASE-ACTIVATING PEPTIDE SUBSTANCE-P PHASE-SHIFTS PITUITARY BRAIN RHYTHMS EXPRESSION Quantitative Peptidomics for Discovery of Circadian-Related Peptides from the Rat Suprachiasmatic Nucleus Article 10.1021/pr300605p 1 JOURNAL OF PROTEOME RESEARCH, v.12, no.2, pp.585 - 593 JOURNAL OF PROTEOME RESEARCH 12 2 585 593 scie scopus 000314558800004 2-s2.0-84873368613 Biochemical Research Methods Biochemistry & Molecular Biology Article GASTRIN-RELEASING-PEPTIDE VASOACTIVE INTESTINAL POLYPEPTIDE CYTOCHROME-OXIDASE ACTIVITY CYCLASE-ACTIVATING PEPTIDE SUBSTANCE-P PHASE-SHIFTS PITUITARY BRAIN RHYTHMS EXPRESSION circadian rhythms suprachiasmatic nucleus (SCN) neuropeptides endogenous peptides label-free quantification quantitative peptidomic analysis