Affiliations: Dipartimento di Fisiologia Generale ed Ambientale,
Università di Napoli Federico II, Napoli, Italy | I.S.P.A.A.M.-C.N.R., Napoli, Italy | Istituto di Zootecnica, Università Cattolica del
Sacro Cuore, Piacenza, Italy | I.G.B. "A. Buzzati Traverso"- C.N.R., Napoli,
Italy
Note: [] Address for correspondence: Prof. Paolo Abrescia, Dipartimento
di Fisiologia Generale ed Ambientale, Università di Napoli Federico II, via
Mezzocannone, 8 – 80134 Napoli, Italy. Tel.: +39 081 2535095; Fax: +39 081
2535090; E-mail: [email protected]
Abstract: Milk is the most important source of Retinol and
α-Tocopherol for calves. These antioxidants save the
food quality and prevent lipid oxidation in the mammary gland and the calf
growing tissues. In Bubalus bubalis, seasonal changes for the plasma
levels of both antioxidants were not found. The levels of Retinol and
α-Tocopherol in the milk were 2 and 1.7 times higher in
winter than in summer, respectively. These levels were correlated with the
plasma level of triiodothyronine, and markedly increased in cows injected with
triiodothyronine in summer. The cytosol from alveolar epithelial cells of
mammary glands was incubated with α-Tocopherol and
^3H-Retinol and, after gel filtration chromatography, both
antioxidants were found associated with proteins migrating as a single peak of
33~kD. The amount of α-Tocopherol and Retinol binding
proteins was 1.5 and 2.3 times higher in winter than in summer respectively.
The Retinol binding proteins migrated as two bands (33 and 16 kD) by
electrophoresis in denaturing and reducing conditions. Our data suggest that
triiodothyronine enhances the transport of both liposoluble antioxidants
through the blood-mammary barrier, and demonstrate that proteins of the mammary
epithelial cells are involved in such a transport.
Keywords: α-Tocopherol, Retinol, triiodothyronine, mammary gland, water buffalo, milk
Journal: BioFactors, vol. 19, no. 3-4, pp. 197-209, 2003
