Rudeen P K, Creighton J, Bylund D B, Petterborg L J, Paredez S
Department of Anatomy & Neurobiology, School of Medicine, University of Missouri-Columbia 65212.
J Pineal Res. 1990;8(2):153-8. doi: 10.1111/j.1600-079x.1990.tb00675.x.
The ontogeny of chick pineal serotonin N-acetyltransferase (NAT) activity was investigated in explanted chick pineal glands at 4, 10 and 21 d of age. Nocturnal levels of the enzyme and the response of the enzyme to light exposure were determined in pineal glands maintained in short-term culture at each age. The results indicate that nocturnal NAT activity was increased in the glands from older birds. Nocturnal levels of NAT activity at the time of the initiation of the experiment were threefold greater in glands from 21-d-old birds as compared to that in glands from 4-day-old chicks. The response to light was similar in all three ages examined; light induced a significant decrease in NAT activity within 60 min in explanted glands from 4-d-old chicks and within 180 min in the glands from the 10- and 21-d-old chicks. A paradoxical transient increase in enzyme activity occurred immediately (within 5 min) following light exposure which was significant in the glands from the youngest chicks, and present, but more variable, in the older chicks. These data indicate that the nocturnal enzyme activity is greater in glands from older birds, but that light exposure of explanted glands initiates a transient rise followed by a decrease in NAT activity at all three ages.
研究了4日龄、10日龄和21日龄雏鸡松果体移植块中鸡松果体血清素N-乙酰基转移酶（NAT）活性的个体发生。测定了各年龄段短期培养的松果体中该酶的夜间水平以及酶对光照的反应。结果表明，老龄鸡的松果体中夜间NAT活性增加。实验开始时，21日龄雏鸡松果体中的NAT夜间活性水平是4日龄雏鸡松果体的三倍。在所研究的三个年龄段中，对光的反应相似；光照后60分钟内，4日龄雏鸡松果体移植块中的NAT活性显著降低，10日龄和21日龄雏鸡松果体中的NAT活性在180分钟内显著降低。光照后立即（5分钟内）出现酶活性的反常短暂增加，这在最年幼雏鸡的松果体中很显著，在老龄雏鸡中也存在，但变化更大。这些数据表明，老龄鸡的松果体中夜间酶活性更高，但移植的松果体在所有三个年龄段接受光照后都会先出现NAT活性的短暂升高，随后降低。
