Shew R L, Kenny A D, Pang P K
Proc Soc Exp Biol Med. 1984 Apr;175(4):444-8. doi: 10.3181/00379727-175-41818.
The effects of bPTH-(1-34), oxidized bPTH-(1-34),[Nle8,Nle18, Tyr34] bPTH-(1-34) amide, and oxidized [Nle8,Nle18,Tyr34]bPTH-(1-34)amide were tested in an in vitro rat uterine assay. When bPTH-(1-34) was treated with hydrogen peroxide (H2O2), the ability of this peptide to reduce oxytocin-stimulated uterine contraction in vitro was no longer evident. An analogue of bPTH-(1-34), in which the methionines at positions 8 and 18 were replaced with norleucine ([Nle8,Nle18,Tyr34]bPTH-(1-34)amide), was capable of reducing oxytocin-stimulated uterine contraction. However, when the [Nle8,Nle18,Tyr34]bPTH-(1-34)amide was oxidized, it retained the ability to reduce uterine contraction. Since we have previously shown that H2O2 oxidation affected only the methionines, these results suggest that the methionines are not necessary for the uterine activity of bPTH-(1-34). We have previously shown that oxidation of bPTH-(1-34) also destroys its blood vessel relaxing activity but has no effect in the rat or the Japanese quail hypercalcemic assays. These data combined with the results of the present studies suggest that the uterine and vascular smooth muscle relaxing properties of bPTH-(1-34) may require the same structural conformation and that this conformation is different from that required for the hypercalcemic action of the peptide.
在一项体外大鼠子宫试验中测试了bPTH-(1-34)、氧化型bPTH-(1-34)、[Nle8,Nle18,Tyr34]bPTH-(1-34)酰胺和氧化型[Nle8,Nle18,Tyr34]bPTH-(1-34)酰胺的作用。当bPTH-(1-34)用过氧化氢（H2O2）处理时，该肽在体外降低催产素刺激的子宫收缩的能力不再明显。bPTH-(1-34)的一种类似物，其中第8位和第18位的甲硫氨酸被正亮氨酸取代（[Nle8,Nle18,Tyr34]bPTH-(1-34)酰胺），能够降低催产素刺激的子宫收缩。然而，当[Nle8,Nle18,Tyr34]bPTH-(1-34)酰胺被氧化时，它仍保留降低子宫收缩的能力。由于我们之前已经表明H2O2氧化仅影响甲硫氨酸，这些结果表明甲硫氨酸对于bPTH-(1-34)的子宫活性不是必需的。我们之前已经表明bPTH-(1-34)的氧化也会破坏其血管舒张活性，但在大鼠或日本鹌鹑高钙血症试验中没有影响。这些数据与本研究结果相结合表明，bPTH-(1-34)的子宫和血管平滑肌舒张特性可能需要相同的结构构象，并且这种构象与该肽的高钙血症作用所需的构象不同。
