Differences in expression and activity of β,β′-carotene-15,15′- oxygenase in liver and duodenum of cattle with yellow or white fat
Pasture-fed cattle show yellow pigmentation of their fat due to β-carotene stored in this tissue. β,β′-Carotene-15,15′-oxygenase (βCO) is an enzyme expressed in different tissues, and it cleaves β-carotene into retinal. We compared the expression and activity of βCO in duodenum and liver of cattle with pigmented or non-pigmented fat. In the duodenum, in situ hybridizations showed expression of βCO in epithelial cells and crypts of the mucosa that was similar in animals from pigmented and non-pigmented fat; liver showed diffuse signal at lobules, but pigmented animals showed higher signals near the portal space. Analyses by real-time reverse-transcription polymerase chain reaction also showed amplification of mRNA for βCO in duodenum and liver, with no difference between pigmented or non-pigmented animals. Enzyme activity was similar in the duodenum, but pigmented animals had higher enzyme activity (p = 0.004) in liver. Cattle with pigmented fat had higher expression and activity of βCO in liver, but its level was not high enough to prevent the storage of β-carotene in adipose tissues.
Document Type: Research Article
Affiliations: 1: Facultad de Estudios Superiores-Cuautitlán, Universidad Nacional Autónoma de México, Queretaro, Qro, Mexico 2: Instituto de Neurobiología, Universidad Nacional Autónoma de México, Queretaro, Qro, Mexico
Publication date: 2007-08-01