Agrawal Y P, Vanha-Perttula T
Department of Anatomy, University of Kuopio, Finland.
Biol Reprod. 1988 Jun;38(5):996-1000. doi: 10.1095/biolreprod38.5.996.
During postnatal development, gamma-glutamyl transpeptidase (gamma-GT), reduced glutathione (GSH), and L-glutamic acid (L-Glu) were assayed in the epididymides of rats at 5-day intervals between 10 and 60 days of age and compared to adult levels. gamma-GT activity (with gamma-glutamyl-p-nitroanilide as substrate) and L-Glu (nicotinamide adenine dinucleotide conversion-dependent assay) were measured photometrically, while GSH (o-phthalaldehyde reaction) was quantified with a fluorometric assay. In immature rats, the epididymal gamma-GT was very low but increased after 25 days of age in the caput and after 50 days of age in the cauda. The enzyme level in the epididymal caput was by far the highest in the adult rat reproductive tissues. The postnatal increase of gamma-GT in epididymal caput and cauda was associated with a decline of its substrate GSH and an accumulation of the product L-Glu. These observations provide evidence for the in vivo hydrolytic activity of gamma-GT and explain the high levels of L-Glu found in the epididymis of rats and other mammals.
在出生后的发育过程中，每隔5天对10至60日龄大鼠的附睾进行γ-谷氨酰转肽酶（γ-GT）、还原型谷胱甘肽（GSH）和L-谷氨酸（L-Glu）的检测，并与成年水平进行比较。以γ-谷氨酰对硝基苯胺为底物测定γ-GT活性（采用光度法），以烟酰胺腺嘌呤二核苷酸转化依赖法测定L-Glu（采用光度法），而采用荧光测定法定量GSH（邻苯二甲醛反应）。在未成熟大鼠中，附睾γ-GT水平非常低，但在25日龄后附睾头γ-GT水平升高，在50日龄后附睾尾γ-GT水平升高。附睾头中的酶水平在成年大鼠生殖组织中是最高的。附睾头和附睾尾中γ-GT的出生后增加与其底物GSH的下降和产物L-Glu的积累有关。这些观察结果为γ-GT的体内水解活性提供了证据，并解释了在大鼠和其他哺乳动物附睾中发现的高水平L-Glu。
