All-trans retinoic acid is increased in the acute phase-related hyporetinemia during Escherichia coli mastitis

摘要

Blood vitamin A profiles, including concentrations of retinol and its active metabolite retinoic acid, were assessed during the peripartum period and during experimentally induced Escherichia coli mastitis in heifers. Serum retinol decreased in all animals in the immediate postpartum period and normalized within 1 wk after parturition. No significant changes were detectable in the concentrations of retinoic acid isomers during puerperium. Following intramammary E. coli infusion, all cows showed moderate symptoms of systemic disease besides the local signs of inflammation. The presence of a systemic acute-phase reaction was documented by fever, increase in serum amyloid A, and decrease in serum albumin. Retinol concentration in serum also decreased spectacularly during coliform mastitis, and the decline was clearly related to the timing of the acute-phase response. Moreover, a significant increase of all-trans retinoic acid, mirrored by a lowering of 13-cis retinoic acid, was detected during the same time period. The 9-cis isomer of retinoic acid was present in all samples, but it remained below the quantification limit.