Jessop D, Sidhu R, Lightman S L
Medical Unit, Westminster Hospital, London, U.K.
Brain Res. 1990 May 14;516(1):41-5. doi: 10.1016/0006-8993(90)90895-i.
Methionine (Met) enkephalin is detectable in rat hypothalamic and neurointermediate lobe (NIL) tissue extracts using a specific radioimmunoassay. Reversed-phase HPLC revealed that only the pentapeptide form was present in the extracts. Total amounts of Met-enkephalin in extracts containing the median eminence (ME), supraoptic nucleus (SON), paraventricular nucleus (PVN), or NIL from control animals were 9.7 +/- 1.6, 0.9 +/- 0.2, 25.2 +/- 6.8 and 14.8 +/- 1.2 pmol respectively (means +/- S.E.M., n = 6). In animals given 340 mmol NaCl/l to drink for 5 days, no significant changes occurred in Met-enkephalin content in the SON or ME, but significant decreases were observed in the NIL and PVN (9.8 +/- 0.8 and 13.6 +/- 1.7 pmol, respectively). Amounts of Met-enkephalin in these tissues were further decreased after 12 days of 340 mmol NaCl/l (3.4 +/- 0.4 and 6.0 +/- 0.6 pmol). These data demonstrate that enkephalin immunoreactivity in the NIL is principally in the form of the Met-enkephalin pentapeptide, and that this peptide is released in response to increased plasma osmolality. The concomitant changes in the PVN and NIL tissue content suggest that the PVN is the source of NIL Met-enkephalin.
使用特定的放射免疫分析法可在大鼠下丘脑和神经中间叶（NIL）组织提取物中检测到甲硫氨酸（Met）脑啡肽。反相高效液相色谱法显示提取物中仅存在五肽形式。来自对照动物的包含正中隆起（ME）、视上核（SON）、室旁核（PVN）或NIL的提取物中甲硫氨酸脑啡肽的总量分别为9.7±1.6、0.9±0.2、25.2±6.8和14.8±1.2 pmol（平均值±标准误，n = 6）。给动物饮用340 mmol NaCl/l 5天，SON或ME中甲硫氨酸脑啡肽含量无显著变化，但NIL和PVN中显著降低（分别为9.8±0.8和13.6±1.7 pmol）。在饮用340 mmol NaCl/l 12天后，这些组织中甲硫氨酸脑啡肽的量进一步降低（3.4±0.4和6.0±0.6 pmol）。这些数据表明，NIL中的脑啡肽免疫反应性主要以甲硫氨酸脑啡肽五肽的形式存在，并且该肽会随着血浆渗透压升高而释放。PVN和NIL组织含量的伴随变化表明PVN是NIL中甲硫氨酸脑啡肽的来源。
