Capaldo Anna, Sciarrillo Rosaria, Valiante Salvatore, Gay Flaminia, Virgilio Francesca, Varlese Maria Grazia, Laforgia Vincenza, Varano Lorenzo
Department of Evolutive and Comparative Biology, University Federico II, 80134 Naples, Italy.
Gen Comp Endocrinol. 2004 Jul;137(3):237-47. doi: 10.1016/j.ygcen.2004.03.011.
The role of neuropeptide Y (NPY) in the modulation of the pituitary-adrenal axis activity in a lizard, Podarcis sicula, was investigated by in vivo NPY administration. The effects were evaluated by examination of the morphological and morphometrical features of the tissues as well as the plasma levels of ACTH, corticosterone, aldosterone, norepinephrine, and epinephrine. Intraperitoneally administered NPY (27 nmol /100g body wt) raised ACTH plasma levels (from 5.23+/-0.06 pg/ml in carrier injected specimens to 6.83+/-0.01 pg/ml, 24 h after the injection). In the steroidogenic cells a strong decrease of lipid amount was found; corticosterone plasma level increased from 6.28+/-0.02 ng/ml in carrier injected lizards to 7.96+/-0.01 ng/ml 24 h after the injection); aldosterone levels were raised from 1.88+/-0.02 ng/ml in carrier injected specimens to 6.38+/-0.05 ng/ml 24 h after the experimental treatment. In the chromaffin tissue, an increase in the number of epinephrine cells and a decrease in the number of norepinephrine cells were observed, decreasing the numeric norepinephrine/epinephrine (NE/E) cell ratio, from 1.4/1 of control specimens to 0.5/1 24 h after NPY administration. Moreover, norepinephrine plasma level were elevated from 922+/-4.30 pg/ml in carrier injected specimens to 3075+/-11.30 pg/ml 24 h after NPY administration; epinephrine plasma level increased from 502+/-2.40 pg/ml in carrier injected specimens to 2759+/-8.70 pg/ml 24 h after the experimental treatment. Consistent with these findings, morphological observations showed many chromaffin cells weakly stained and with a reduced content of secretory granules. These results suggest that, in P. sicula, NPY may play a role in the modulation of the pituitary-adrenal axis activity. Previous studies localized NPY in the epinephrine cells of P. sicula adrenal gland; taken together, these results suggest that this peptide might participate in the regulation of adrenal gland activity, enhancing corticosteroid and catecholamine secretion in a paracrine/autocrine manner. The mechanism of action of NPY is discussed.
通过体内注射神经肽Y（NPY），研究了其对意大利壁蜥（Podarcis sicula）垂体-肾上腺轴活性的调节作用。通过检查组织的形态学和形态计量学特征以及促肾上腺皮质激素（ACTH）、皮质酮、醛固酮、去甲肾上腺素和肾上腺素的血浆水平来评估其作用效果。腹腔注射NPY（27 nmol/100g体重）可提高ACTH血浆水平（从注射载体的标本中的5.23±0.06 pg/ml升至注射后24小时的6.83±0.01 pg/ml）。在类固醇生成细胞中发现脂质含量大幅下降；皮质酮血浆水平从注射载体的蜥蜴中的6.28±0.02 ng/ml升至注射后24小时的7.96±0.01 ng/ml；醛固酮水平从注射载体的标本中的1.88±0.02 ng/ml升至实验处理后24小时的6.38±0.05 ng/ml。在嗜铬组织中，观察到肾上腺素细胞数量增加，去甲肾上腺素细胞数量减少，去甲肾上腺素/肾上腺素（NE/E）细胞数量比从对照标本的1.4/1降至NPY给药后24小时的0.5/1。此外，去甲肾上腺素血浆水平从注射载体的标本中的922±4.30 pg/ml升至NPY给药后24小时的3075±11.30 pg/ml；肾上腺素血浆水平从注射载体的标本中的502±2.40 pg/ml升至实验处理后24小时的2759±8.70 pg/ml。与这些发现一致，形态学观察显示许多嗜铬细胞染色较弱且分泌颗粒含量减少。这些结果表明，在意大利壁蜥中，NPY可能在垂体-肾上腺轴活性的调节中发挥作用。先前的研究将NPY定位在意大利壁蜥肾上腺的肾上腺素细胞中；综合这些结果表明，该肽可能以旁分泌/自分泌方式参与肾上腺活动的调节，增强皮质类固醇和儿茶酚胺的分泌。本文还讨论了NPY的作用机制。
