Werner Elizabeth A, Deluca Hector F
Department of Biochemistry, University of Wisconsin at Madison, Madison, Wisconsin 53706, USA.
Am J Physiol Endocrinol Metab. 2002 Mar;282(3):E672-8. doi: 10.1152/ajpendo.00280.2001.
Retinoic acid (RA) is essential for cellular growth and differentiation in developing and adult animals. The central nervous system (CNS) suffers developmental defects if embryonic levels of RA are too high or too low. The production and function of RA in adult brain are unclear. We report that RA is present throughout the brain and spinal cord of adult, vitamin A-deficient (VAD) rats treated with a physiological amount of all-trans-retinol. The hippocampus/cortex contained the highest proportion of RA in the brain (27.2 +/- 2.9% of the organic phase radioactivity, and 23.5 +/- 0.8% of the organic phase radioactivity extracted from spinal cord was RA). RA comprises a higher proportion of the retinoid pool in the CNS compared with amounts reported in other target tissues (E Werner and HF DeLuca. Arch Biochem Biophys 393: 262-270, 2001). However, RA is not preferentially transported from the blood to the brain. There were 2.90 +/- 0.20 fmol RA/g tissue transported to the brain of VAD rats treated with 2.00 nmol [20-(3)H]all-trans-retinoic acid, but higher amounts of RA were delivered to the liver, testis, and spleen. Because RA is not transported preferentially to brain, this tissue likely synthesizes RA more efficiently than other target tissues.
维甲酸（RA）对于发育中和成年动物的细胞生长及分化至关重要。如果胚胎期的RA水平过高或过低，中枢神经系统（CNS）就会出现发育缺陷。RA在成年大脑中的产生及功能尚不清楚。我们报告称，在用生理量的全反式视黄醇处理的成年维生素A缺乏（VAD）大鼠的整个脑和脊髓中均存在RA。海马体/皮质中RA在脑中所占比例最高（占有机相放射性的27.2±2.9%；从脊髓中提取的有机相放射性中，23.5±0.8%为RA）。与其他靶组织中报告的量相比，RA在中枢神经系统的类视黄醇池中所占比例更高（E·沃纳和HF·德卢卡。《生物化学与生物物理学文献》3:262 - 270，2001年）。然而，RA并非优先从血液转运至大脑。用2.00 nmol [20 -（3）H]全反式视黄酸处理的VAD大鼠，每克组织转运至大脑的RA为2.90±0.20 fmol，但输送至肝脏、睾丸和脾脏的RA量更高。由于RA并非优先转运至大脑，该组织可能比其他靶组织更高效地合成RA。
