Malendowicz L K, Nussdorfer G G, Markowska A, Tortorella C, Nowak M, Warchol J B
Department of Histology and Embryology, School of Medicine, Poznan, Poland.
Neuropeptides. 1994 Jan;26(1):47-53. doi: 10.1016/0143-4179(94)90092-2.
A 6-day subcutaneous (s.c.) treatment of adult rats with NMU-8 (1.5 or 6 micrograms/100 g/day) increased the average volume of zona fasciculata cells and decreased the number of zona reticularis cells in the adrenal cortex. The lower dose of NMU-8 did not change blood ACTH concentration and adrenal weight, but it notably enhanced serum corticosterone level and basal corticosterone output by adrenal slices. ACTH blood level increased after ether stress in both control and NMU-8-treated rats, but stress-evoked rise in serum corticosterone was observed only in control rats. The higher dose of NMU-8 increased the level of circulating ACTH; however, it decreased adrenal weight and had no effect on serum corticosterone concentration and basal corticosterone output by adrenal slices. NMU-8 (10(-10)/10(-6) M) did not affect basal and ACTH-stimulated corticosterone yield by isolated adrenocortical cells, nor did it change their cytosolic Ca2+ concentration. NMU-8 (10(-8) M) markedly raised basal corticosterone secretion by adrenal slices (including cortex and medulla); higher concentrations of NMU-8 (10(-7)/10(-6) M) were ineffective on basal corticosterone secretion, but strongly inhibited the response to ACTH stimulation. On the ground of these findings it seems reasonable to suggest that NMU-8 exerts a biphasic effect on the function of the peripheral branch of the hypothalamo-pituitary-adrenal axis in rats: NMU-8 at low doses directly stimulates the function and growth of the adrenal cortex, while at high doses exerts a direct inhibitory action.(ABSTRACT TRUNCATED AT 250 WORDS)
用NMU - 8（1.5或6微克/100克/天）对成年大鼠进行为期6天的皮下治疗，增加了肾上腺皮质束状带细胞的平均体积，并减少了网状带细胞的数量。较低剂量的NMU - 8未改变血液促肾上腺皮质激素（ACTH）浓度和肾上腺重量，但显著提高了血清皮质酮水平以及肾上腺切片的基础皮质酮产量。在对照大鼠和接受NMU - 8治疗的大鼠中，乙醚应激后ACTH血液水平均升高，但仅在对照大鼠中观察到应激引起的血清皮质酮升高。较高剂量的NMU - 8增加了循环ACTH水平；然而，它降低了肾上腺重量，并且对血清皮质酮浓度和肾上腺切片的基础皮质酮产量没有影响。NMU - 8（10⁻¹⁰/10⁻⁶ M）不影响分离的肾上腺皮质细胞的基础和ACTH刺激的皮质酮产量，也不改变其胞质Ca²⁺浓度。NMU - 8（10⁻⁸ M）显著提高了肾上腺切片（包括皮质和髓质）的基础皮质酮分泌；更高浓度的NMU - 8（10⁻⁷/10⁻⁶ M）对基础皮质酮分泌无效，但强烈抑制对ACTH刺激的反应。基于这些发现，似乎有理由认为NMU - 8对大鼠下丘脑 - 垂体 - 肾上腺轴外周分支的功能具有双相作用：低剂量的NMU - 8直接刺激肾上腺皮质的功能和生长，而高剂量则发挥直接抑制作用。（摘要截断于250字）
