LACRIMAL GLAND UPTAKE AND METABOLISM OF ASCORBIC-ACID
LACRIMAL GLAND UPTAKE AND METABOLISM OF ASCORBIC-ACID
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DOI：
10.3181/00379727-202-43529
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发表时间：
1993-02-01
影响因子：
--
通讯作者：
ROSE, RC
中科院分区：
文献类型：
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作者：
DREYER, R;ROSE, RC
抗坏血酸被认为有助于保护眼睛免受辐射、氧毒性和擦伤的潜在破坏性影响。角膜的前表面特别容易受到来自每个威胁的损害。我们考虑了猪的泪腺具有运输和/或代谢能力来隔离还原或氧化形式的抗坏血酸并使其准备在泪液中分泌的可能性。将新鲜泪腺切片在生理缓冲液中孵育，并在40分钟孵育期内暴露于小于或等于12 μ M C-14标记的抗坏血酸或脱氢-L-抗坏血酸。脱水-l-抗坏血酸的吸收程度比还原化合物更大。 与任一底物孵育后，从组织中回收的C-14-标记至少75%为抗坏血酸形式。摄取的还原和氧化的基板进行到一个组织介质的比例超过统一，前者被阻止的存在下，未标记的抗坏血酸在洗澡的介质，但不受影响的Na+从浴中去除。抑制细胞代谢能后，两种底物的摄取均减少。泪腺在这种昼夜活动的动物物种具有运输和代谢能力，可以分泌抗坏血酸进入眼泪。这可能有助于保护角膜上皮免受各种形式的损伤。
Ascorbic acid is thought to contribute to protection against the potentially damaging effects of radiation, oxygen toxicity, and abrasion in the eye. The anterior surface of the cornea is particularly subject to insult from each threat. We considered the possibility that the lacrimal gland of pigs has transport and/or metabolic capability to sequester the reduced or oxidized form of ascorbic acid and prepare it for secretion in the tears. Slices of fresh lacrimal gland were incubated in a physiologic buffer and exposed to less-than-or-equal-to 12 muM C-14-labeled ascorbic acid or dehydro-l-ascorbic acid over 40-min incubation periods. Dehydro-l-ascorbic acid was taken up to a greater extent than the reduced compound. C-14-Label recovered from the tissue was at least 75% in the form of ascorbic acid after incubation with either substrate. Uptake of both the reduced and oxidized substrates proceeded to a tissue to medium ratio in excess of unity; the former was prevented by the presence of nonlabeled ascorbate in the bathing medium, but was unaffected by the removal of Na+ from the bath. The uptake of both substrates was less after inhibition of cellular metabolic energy. The lacrimal gland in this diurnal animal species has transport and metabolic capabilities that could serve in secretion of ascorbic acid into tears. This might help to protect the corneal epithelium against various forms of damage.