Saito M, Nakamura I, Miyagawa I, Nishi K
Department of Urology, Tottori University Faculty of Medicine.
Nihon Hinyokika Gakkai Zasshi. 1997 Aug;88(8):737-45. doi: 10.5980/jpnjurol1989.88.737.
As there is increasing evidence that diabetes induces changes in the plasma levels of endothelins (ETs) and the properties of the ET receptors in peripheral tissues and there are reports indicating the presence of significant amounts of endothelin binding sites in the mammalian vasa deferentia, we studied possible alterations in ET receptor characteristics in the vasa deferentia of rats and rabbits.
Diabetes was induced with i.v. injections of streptozotocin (65 mg/kg) and alloxan (100 mg/kg) in rats and rabbits, respectively. We investigated the binding characteristics of endothelin (ET) receptors in the vasa deferentia of four and five month experimentally-induced diabetic rats and rabbits, respectively. The densities and pharmacological properties of ET receptors in the rat and rabbit vasa deferentia were examined by radioligand receptor binding studies using [125I]ET-1.
RESULTS & CONCLUSION: Receptor binding experiments with [125I]ET-1 revealed a dramatic upregulation in the expression of a single class of specific, saturable, high affinity of [125I]ET-1 binding sites in the diabetic rats but not in the vasa deferentia of diabetic rabbits. ET-1 (non-selective), ET-3 (ETC selective), BQ 610 (ETA selective) and IRL 1620 (ETB selective) compounds inhibited [125I]ET-binding to the rats and rabbits vasa deferentia consistent with the predominance of ETA receptors in these tissues.
鉴于越来越多的证据表明糖尿病会导致外周组织中内皮素（ETs）血浆水平及ET受体特性发生变化，且有报道指出哺乳动物输精管中存在大量内皮素结合位点，我们研究了大鼠和家兔输精管中ET受体特性可能发生的改变。
分别通过静脉注射链脲佐菌素（65mg/kg）和四氧嘧啶（100mg/kg）诱导大鼠和家兔患糖尿病。我们分别研究了4个月和5个月实验性糖尿病大鼠和家兔输精管中内皮素（ET）受体的结合特性。使用[125I]ET-1通过放射性配体受体结合研究检测大鼠和家兔输精管中ET受体的密度和药理学特性。
用[125I]ET-1进行的受体结合实验显示，糖尿病大鼠输精管中一类特异性、可饱和、高亲和力的[125I]ET-1结合位点的表达显著上调，而糖尿病家兔的输精管中未出现这种情况。ET-1（非选择性）、ET-3（ET C选择性）、BQ 610（ET A选择性）和IRL 1620（ET B选择性）化合物抑制[125I]ET与大鼠和家兔输精管的结合，这与这些组织中ET A受体占主导地位一致。
