Nussey S S, Prysor-Jones R A, Taylor A, Ang V T, Jenkins J S
Department of Medicine II, St George's Hospital Medical School, London.
J Endocrinol. 1987 Oct;115(1):141-9. doi: 10.1677/joe.0.1150141.
The concentrations of immunoreactive oxytocin and arginine vasopressin (AVP) and their respective neurophysins (NpI and NpII) were compared in bovine adrenal cortex and medulla. While the concentration of AVP was similar in both tissues there was more NpII in the medulla. The medulla also contained much more oxytocin and NpI than the cortex. The extracted AVP and oxytocin had identical retention times to those of the synthetic peptides on high-performance liquid chromatography (HPLC) and were biologically active in assays for antidiuretic and milk-ejection activity (with potencies of 310 units/mg and 340 units/mg respectively). Adrenal NpI and NpII behaved identically to commercially available neurohypophysial proteins on HPLC. Oxytocin, NpI and AVP were assayed in five subcellular fractions of bovine adrenal medulla prepared on discontinuous sucrose gradients. A high proportion of each co-localized with noradrenaline and adrenaline in the chromaffin granule fraction. Binding of [3H]AVP and [3H]oxytocin to crude bovine adrenal medulla membranes was dependent upon both time and temperature. The binding sites were specific and saturable: studies with the V1 AVP antagonist d(CH2)5Tyr(Me)AVP and the V2 agonist 1-deamino-8-D-AVP indicated that the AVP receptor was V1 in specificity. Scatchard plots showed that each ligand interacted with a single high-affinity, low-capacity binding site: oxytocin dissociation constant (Kd) 3.1 +/- 0.29 nmol/l, maximum binding capacity (Bmax) 89.6 +/- 18.4 fmol/mg protein (n = 3); AVP Kd 0.73 +/- 0.02 nmol/l, Bmax 26.5 +/- 8.3 fmol/mg protein (n = 3).(ABSTRACT TRUNCATED AT 250 WORDS)
对牛肾上腺皮质和髓质中免疫反应性催产素、精氨酸加压素（AVP）及其各自的神经垂体素（NpI和NpII）的浓度进行了比较。虽然两种组织中AVP的浓度相似，但髓质中的NpII更多。髓质中含有的催产素和NpI也比皮质多得多。提取的AVP和催产素在高效液相色谱（HPLC）上与合成肽具有相同的保留时间，并且在抗利尿和排乳活性测定中具有生物活性（效力分别为310单位/毫克和340单位/毫克）。肾上腺NpI和NpII在HPLC上的行为与市售神经垂体蛋白相同。在不连续蔗糖梯度上制备的牛肾上腺髓质的五个亚细胞组分中检测了催产素、NpI和AVP。每种物质的很大一部分与嗜铬颗粒组分中的去甲肾上腺素和肾上腺素共定位。[3H]AVP和[3H]催产素与粗制牛肾上腺髓质膜的结合取决于时间和温度。结合位点具有特异性且可饱和：用V1 AVP拮抗剂d(CH2)5Tyr(Me)AVP和V2激动剂1-脱氨基-8-D-AVP进行的研究表明，AVP受体在特异性上是V1型。Scatchard图显示，每种配体与单个高亲和力、低容量结合位点相互作用：催产素解离常数（Kd）3.1±0.29纳摩尔/升，最大结合容量（Bmax）89.6±18.4飞摩尔/毫克蛋白（n = 3）；AVP Kd 0.73±0.02纳摩尔/升，Bmax 26.5±8.3飞摩尔/毫克蛋白（n = 3）。（摘要截断于250字）
