Coulter C L, Browne C A, McMillen I C
Department of Physiology, Monash University, Clayton, Victoria, Australia.
Endocrinology. 1990 Jul;127(1):330-6. doi: 10.1210/endo-127-1-330.
We have measured the content of enkephalin-containing peptides (ENK-containing peptides) in adrenal gland extracts from fetal sheep between 68-142 days gestation and from adult sheep. We investigated whether there are changes in the post-translational processing of ENK-containing peptides in the fetal sheep adrenal gland with increasing gestational age. ENK-containing peptides in adrenal extracts from fetal sheep (68-142 days gestation) and adult sheep were separated using gel filtration chromatography and the ENK immunoreactivity (ENK-IR) was measured using RIAs for Met-enkephalin-Arg6,Phe7 immunoreactivity (MERF-IR) and Met-o-enk immunoreactivity (MET-O-ENK-IR). The MET-O-ENK-IR in fetal and adult sheep adrenal extracts was distributed in four main peaks, which corresponded to mol wt (MW) ranges of more than 12, 7-12, 3-7, and less than 3 kDa. There was a significant increase (P less than 0.05) in the total ENK-IR content of the fetal adrenal between 68-78 (42.4 +/- 19.2 ng/adrenal) and 100-121 (320.1 +/- 142.6 ng/adrenal) days gestation. There was also a significant increase in the proportion of MET-O-ENK-IR and MERF in the less than 3 kDa range between 68-78 (MET-O-ENK, 6.8 +/- 2.7%; MERF, 10.3 +/- 1.4%) and 100-121 (MET-O-ENK, 24.4 +/- 5.1%; MERF, 26.2 +/- 5.8%) days gestation, with an associated decrease in the ratio of ENK-containing peptides in the high MW form (i.e. greater than 3 kDa) compared to those in the low MW (less than 3 kDa) forms (10.4 +/- 2.5 at 68-78 days gestation; 4.2 +/- 1.1 at 100-121 days gestation). There was also a significant decrease in the percentage of MET-O-ENK in the 12 kDa range after 139 days gestation (125-135 days gestation, 20.4 +/- 2.2%; 139-142 days gestation, 4.0 +/- 2.1%). Therefore, there is an increase in the proportion of the low MW forms of ENK-containing peptides in the fetal sheep adrenal with advancing gestational age, which may reflect changes in the post-translational processing of the precursor proenkephalin-A during development.
我们测定了妊娠68 - 142天的胎羊及成年羊肾上腺提取物中含脑啡肽肽段（含ENK肽段）的含量。我们研究了随着胎龄增加，胎羊肾上腺中含ENK肽段的翻译后加工过程是否存在变化。使用凝胶过滤色谱法分离胎羊（妊娠68 - 142天）和成年羊肾上腺提取物中的含ENK肽段，并使用针对甲硫氨酸脑啡肽 - Arg6，Phe7免疫反应性（MERF - IR）和甲硫氨酸 - o - 脑啡肽免疫反应性（MET - O - ENK - IR）的放射免疫分析法测定ENK免疫反应性（ENK - IR）。胎羊和成年羊肾上腺提取物中的MET - O - ENK - IR分布在四个主要峰中，分别对应分子量（MW）范围大于12 kDa、7 - 12 kDa、3 - 7 kDa和小于3 kDa。妊娠68 - 78天（42.4±19.2 ng/肾上腺）至100 - 121天（320.1±142.6 ng/肾上腺）时，胎羊肾上腺中总ENK - IR含量显著增加（P＜0.05）。在妊娠68 - 78天（MET - O - ENK，6.8±2.7%；MERF，10.3±1.4%）至100 - 121天（MET - O - ENK，24.4±5.1%；MERF，26.2±5.8%）时，小于3 kDa范围内的MET - O - ENK - IR和MERF比例也显著增加，同时与高分子量形式（即大于3 kDa）相比，低分子量（小于3 kDa）形式的含ENK肽段比例下降（妊娠68 - 78天时为10.4±2.5；妊娠100 - 121天时为4.2±1.1）。妊娠139天后（妊娠125 - 135天，20.4±2.2%；妊娠139 - 142天，4.0±2.1%），12 kDa范围内的MET - O - ENK百分比也显著下降。因此，随着胎龄增加，胎羊肾上腺中低分子量形式的含ENK肽段比例增加，这可能反映了发育过程中前体脑啡肽原 - A翻译后加工的变化。
