¹Department of Medical Biochemistry, Faculty of Medicine, İnönü University, Malatya, Turkey
²Department of Medical Biochemistry, Graduate Institute of Health Sciences, İnönü University,Malatya, Turkey
³Department of Analytical Chemistry, Faculty of Pharmacy, İnönü University, Malatya, Turkey
⁴Department of Biostatistics and Medical Informatics, Faculty of Medicine, İnönü University, Malatya, Turkey
⁵Department of Dermatology, Faculty of Medicine, İnönü University, Malatya, Turkey
⁶Department of Internal Medical Sciences, Faculty of Medicine, İnönü University, Malatya, Turkey
⁷Department of Internal Medical Sciences, Faculty of Medicine, İnönü University, Malatya, Turkey
⁸Department of Medical Biochemistry, Faculty of Medicine, Pamukkale University, Denizli, Turkey
⁹Department of Medical Biochemistry, Faculty of Medicine, İnönü University, Malatya, Turkey Circadian disturbances are known to affect lipid metabolism. Most of the phospholipid metabolites have been shown to be under circaian control by metabolomics studies. Moreover, genes related to glycerolipid synthesis were reported to be circadianly regulated. Data from various studies revealed a relationship between glycerolipid metabolism and circadian misalignments. Some proteins responsible for transfer of phospholipids among plasma lipoproteins or membranes include phospholipid transfer proteins (PLTP), lecithin cholesterol acyltransferase (LCAT), secretory phospholipase A2 (sPLA2), endothelial lipase (EL), exhibits circadian oscillation. However no data are available as to whether circadian disturbances can influence phospholipid trafficking among HDL, erythrocytes and serum. To this end, , four conditions associated with circadian disturbances including type 2 diabetes, prediabetes with metformin usage, psoriasis and night-shift work were investigated for phospholipid trafficking. Indices of circadian misalignments, plasma melatonin and cortisol levels, were determined by ELISA and chemiluminescence methods respectively. Serum levels of PLTP, LCAT, EL and sPLA2 levels were analyzed by ELISA. Phospholipid compositions were investigated by two-dimensional HPTLC and/or HPLC. Results by HPLC indicated that PE/PC ratios in erythrocyte lysates of diabetes and metformin groups were found to be significantly lower compared to that of controls which might be associated with the lower levels of LCAT, EL and PLTP levels measured. Altered plasma melatonin levels indicated circadian misalignments in these conditions. However, in psoriasis and night-shift groups, circadian indexes did not match with the PE/PC ratios in erythrocytes as it was in diabetes and metformin groups. We therefore conclude that circadian as well as metabolic disturbances both might have a role in phospholipid trafficking. Keywords : Chronobiology disorders; phospholipids; erythrocyte membrane; phospholipid transfer proteins; LCAT protein; LIPG protein; Phospholipases A2, secretory