Mazumdar Minakshi, Lal Bechan, Sakharkar Amul J, Deshmukh Makrand, Singru Praful S, Subhedar Nishikant
Department of Pharmaceutical Sciences, RTM Nagpur University Campus, Nagpur, India.
Gen Comp Endocrinol. 2006 Nov;149(2):190-6. doi: 10.1016/j.ygcen.2006.05.012. Epub 2006 Jul 7.
Although neuropeptide Y (NPY) has been known to influence the release of luteinizing hormone (LH) and growth hormone (GH) from the pituitary gland of teleosts, the NPY receptor subtypes involved in the regulatory processes have not been fully defined. An attempt has been made to study the involvement of NPY Y1 receptors, if any, in mediating the NPY-triggered stimulation of the LH and GH secreting cells in the pituitary of the catfish, Clarias batrachus. NPY (10 ng/g of body wt) or NPY Y1 receptor agonist (Leu(31)-Pro(34)-NPY, 3 ng/g of body wt) were administered by the intracranial route and the responses by the LH and GH cells in the pituitary were investigated with the help of immunocytochemistry. Both the agents caused a highly significant decrease (P<0.001) in the immunoreactivity of LH cells. However, the treatment with NPY Y1 receptor antagonist (BIBP 3226, 1 ng/g of body wt), prior to NPY or NPY Y1 agonist, blocked the response by the LH cells; the profile of the cells was quite similar to that of the saline-injected control fish. GH cells also showed similar pattern of responses to these treatments. While NPY and NPY Y1 receptor agonist caused significant (P<0.001) decrease in the GH immunoreactivity, pretreatment with the NPY Y1 antagonist blocked the response. These results suggest that NPY may exercise a secretogogue-like action on the LH and GH cells in the pituitary of C. batrachus via NPY Y1 receptors.
尽管已知神经肽Y（NPY）会影响硬骨鱼垂体中促黄体生成素（LH）和生长激素（GH）的释放，但参与这些调节过程的NPY受体亚型尚未完全明确。本研究旨在探讨NPY Y1受体（若存在）是否参与介导鲶鱼（Clarias batrachus）垂体中NPY触发的对LH和GH分泌细胞的刺激作用。通过颅内注射给予NPY（10 ng/g体重）或NPY Y1受体激动剂（Leu(31)-Pro(34)-NPY，3 ng/g体重），并借助免疫细胞化学方法研究垂体中LH和GH细胞的反应。两种药物均导致LH细胞的免疫反应性显著降低（P<0.001）。然而，在给予NPY或NPY Y1激动剂之前，先用NPY Y1受体拮抗剂（BIBP 3226，1 ng/g体重）处理，可阻断LH细胞的反应；细胞形态与注射生理盐水的对照鱼非常相似。GH细胞对这些处理也表现出类似的反应模式。虽然NPY和NPY Y1受体激动剂导致GH免疫反应性显著降低（P<0.001），但用NPY Y1拮抗剂预处理可阻断该反应。这些结果表明，NPY可能通过NPY Y1受体对鲶鱼垂体中的LH和GH细胞发挥类似促分泌素的作用。
