Ramírez M, Sánchez B, Aréchaga G, Lardelli P, Venzon D, García S, Ozaita A, de Gandarias J M
Department of Physiology, Medical School, University of the Basque Country, Leioa, Spain.
Neuroendocrinology. 1992 Dec;56(6):926-9. doi: 10.1159/000126326.
The levels of specific soluble aspartyl aminopeptidase activity were assayed in retina, occipital cortex, anterior pituitary, posterior pituitary, pineal gland and serum of adult male rats, using Asp-2-naphthylamide as substrate, in a 12:12 h light:dark cycle (7-19 h light). Significant diurnal variations appeared in retina, pineal gland, occipital cortex and serum. In addition, different patterns of diurnal variation of the enzymatic activity were observed in the tissues analyzed. A regular increase of the activity was noticed at the end of the dark period in all the tissues as a common feature, except in serum, in which the enzymatic activity reached a peak in the middle of the light period, decreasing progressively during the dark hours. After the last hours of darkness, the pattern of variation in the activity differed in each tissue. These diurnal variations in aspartyl aminopeptidase activity could reflect the functional status of its putative endogenous substrates, such as angiotensin II, and it may also suggest the existence of differential regulatory mechanisms associated with each location.
以Asp - 2 - 萘酰胺为底物，在12:12小时光照：黑暗周期（7 - 19小时光照）条件下，测定成年雄性大鼠视网膜、枕叶皮质、垂体前叶、垂体后叶、松果体和血清中特异性可溶性天冬氨酰氨基肽酶的活性水平。视网膜、松果体、枕叶皮质和血清中出现了显著的昼夜变化。此外，在所分析的组织中观察到了酶活性昼夜变化的不同模式。除血清外，所有组织在黑暗期结束时酶活性均有规律增加，这是一个共同特征，血清中的酶活性在光照期中期达到峰值，在黑暗期逐渐降低。在黑暗的最后几个小时后，各组织中酶活性的变化模式有所不同。天冬氨酰氨基肽酶活性的这些昼夜变化可能反映了其假定的内源性底物（如血管紧张素II）的功能状态，也可能表明每个部位存在不同的调节机制。
