Siawrys Gabriela, Bogacka Iwona, Okrasa S, Kamiński T, Przała Jadwiga
Department of Animal Physiology, University of Warmia and Mazury in Olsztyn, 10-718 Olsztyn-Kortowo 5, Poland.
Acta Vet Hung. 2003;51(3):353-69. doi: 10.1556/AVet.51.2003.3.10.
The direct effects of alpha- and beta-adrenergic agents on PRL and beta-endorphin (beta-END) secretion in vitro by porcine pituitary cells have been investigated. Pituitary glands were obtained from mature gilts, which were ovariectomised (OVX) one month before slaughter. Ovariectomised gilts, assigned to four groups, were primed with: (1) vehicle (OVX); (2) and (3) oestradiol benzoate (EB; 2.5 mg/100 kg b.w.) at 30-36 h (OVX+EB I) and 60-66 h (OVX+EB II) before slaughter, respectively; and (4) progesterone (P4; 120 mg/100 kg b.w.) for 5 consecutive days before slaughter (OVX+P4). Isolated anterior pituitary cells were submitted to 3.5 h incubation in the presence of GnRH, alpha- and beta-adrenergic agonists [phenylephrine (PHEN) and isoproterenol (ISOP), respectively], or alpha- and beta-adrenergic blockers [phentolamine (PHENT) and propranolol (PROP), respectively]. The culture media were assayed for PRL (exp. I) and beta-endorphin-like immunoreactivity (beta-END-LI) (experiment II). In experiment I, GnRH did not influence PRL release by pituitary cells in all experimental groups. Some of tested doses of adrenergic agonists, PHEN and ISOP, increased PRL release from pituitary cells of OVX gilts, but not from those of OVX+EB I animals. In the OVX+EB II group, PHEN alone, but ISOP with PROP, potentiated PRL secretion by the cells. In OVX+P4 animals, PHEN alone or in combination with PHENT and also ISOP alone or with PROP enhanced PRL output from the cells. In experiment II, addition of GnRH increased beta-END-LI release from pituitary cells only in the OVX+EB II group. PHEN and PHENT potentiated beta-END-LI secretion by pituitary cells in OVX+EB II and OVX+P4 groups, while ISOP and PROP increased beta-END-LI secretion by the cells of OVX and OVX+EB II animals. In turn, in the OVX+EB I group, effect of PHENT and PROP on PRL secretion by pituitary cells was inhibitory. In conclusion, our results suggest that adrenergic agents can modulate PRL and beta-END secretion by porcine pituitary cells in a manner dependent on the hormonal status of gilts.
研究了α-和β-肾上腺素能药物对猪垂体细胞体外分泌催乳素（PRL）和β-内啡肽（β-END）的直接影响。垂体取自成熟母猪，这些母猪在屠宰前一个月进行了卵巢切除术（OVX）。将卵巢切除的母猪分为四组，分别用以下物质进行预处理：（1）溶剂（OVX）；（2）和（3）分别在屠宰前30 - 36小时（OVX + EB I）和60 - 66小时（OVX + EB II）注射苯甲酸雌二醇（EB；2.5 mg/100 kg体重）；（4）在屠宰前连续5天注射孕酮（P4；120 mg/100 kg体重）（OVX + P4）。分离的垂体前叶细胞在存在促性腺激素释放激素（GnRH）、α-和β-肾上腺素能激动剂[分别为去氧肾上腺素（PHEN）和异丙肾上腺素（ISOP）]或α-和β-肾上腺素能阻滞剂[分别为酚妥拉明（PHENT）和普萘洛尔（PROP）]的情况下孵育3.5小时。对培养基进行PRL（实验I）和β-内啡肽样免疫反应性（β-END-LI）（实验II）检测。在实验I中，GnRH对所有实验组垂体细胞的PRL释放均无影响。一些测试剂量的肾上腺素能激动剂PHEN和ISOP可增加OVX母猪垂体细胞的PRL释放，但对OVX + EB I组动物的垂体细胞无此作用。在OVX + EB II组中，单独使用PHEN可增强细胞的PRL分泌，而ISOP与PROP联合使用时也有此作用。在OVX + P4组动物中，单独使用PHEN或与PHENT联合使用，以及单独使用ISOP或与PROP联合使用均可增强细胞的PRL分泌。在实验II中，仅在OVX + EB II组中，添加GnRH可增加垂体细胞的β-END-LI释放。PHEN和PHENT可增强OVX + EB II组和OVX + P4组垂体细胞的β-END-LI分泌，而ISOP和PROP可增加OVX组和OVX + EB II组动物细胞的β-END-LI分泌。相反，在OVX + EB I组中，PHENT和PROP对垂体细胞PRL分泌的作用是抑制性的。总之，我们的结果表明，肾上腺素能药物可以根据母猪的激素状态，以一种依赖的方式调节猪垂体细胞的PRL和β-END分泌。
