Barb C R, Matteri R L
USDA, ARS, Animal Physiology Research Unit, Russell Research Center, P.O. Box 5677, Athens, GA 30604-5677, USA.
Domest Anim Endocrinol. 2005 Apr;28(3):331-7. doi: 10.1016/j.domaniend.2004.09.005. Epub 2004 Oct 26.
To test the hypothesis that orexin-B acts directly on the anterior pituitary to regulate LH and growth hormone (GH) secretion, anterior pituitary cells from prepuberal gilts were studied in primary culture. On day 4 of culture, 10(5) cells/well were challenged with 0.1, 10 or 1000 nM GnRH; 10, 100 or 1000 nM [Ala15]-hGRF-(1-29)NH2 or 0.1, 1, 10 or 100 nM, orexin-B individually or in combinations with 0.1 and 1000 nM GnRH or 10 and 1000 nM GRF. Secreted LH and GH were measured at 4 h after treatment. Basal LH and GH secretion (control; n = 6 pigs) was 183 +/- 18 and 108 +/- 4.8 ng/well, respectively. Relative to control at 4 h, all doses of GnRH and GRF increased (P < 0.0001) LH and GH secretion, respectively. All doses of orexin-B increased (P < 0.01) LH secretion, except for the 0.1 nM dose. Basal GH secretion was unaffected by orexin-B. Addition of 1, 10 or 100 nM orexin-B in combinations with 0.1 nM GnRH increased (P < 0.001) LH secretion compared to GnRH alone. Only 0.1 nM (P = 0.06) and 100 nM (P < 0.001) orexin-B in combinations with 1000 nM GnRH increased LH secretion compared to GnRH alone. All doses of orexin-B in combination with 1000 nM GRF suppressed (P < 0.0001) GH secretion compare to GRF alone, while only 0.1 nM orexin-B in combination with 10 nM GRF suppressed (P < 0.01) GH secretion compared to GRF. These results indicate that orexin may directly modulate LH and GH secretion at the level of the pituitary gland.
为了验证食欲素 - B直接作用于垂体前叶以调节促黄体生成素（LH）和生长激素（GH）分泌的假说，对初情期前小母猪的垂体前叶细胞进行了原代培养研究。在培养的第4天，每孔接种10⁵个细胞，分别用0.1、10或1000 nM的促性腺激素释放激素（GnRH）；10、100或1000 nM的[丙氨酸¹⁵]-人促生长激素释放因子（hGRF）-(1 - 29)NH₂；或0.1、1、10或100 nM的食欲素 - B单独处理，或与0.1和1000 nM的GnRH或10和1000 nM的GRF联合处理。处理后4小时测量分泌的LH和GH。基础LH和GH分泌（对照组；n = 6头猪）分别为183±18和108±4.8 ng/孔。与4小时时的对照组相比，所有剂量的GnRH和GRF分别增加了（P < 0.0001）LH和GH的分泌。除0.1 nM剂量外，所有剂量的食欲素 - B均增加了（P < 0.01）LH的分泌。基础GH分泌不受食欲素 - B的影响。与单独使用GnRH相比，联合使用1、10或100 nM的食欲素 - B与0.1 nM的GnRH可增加（P < 0.001）LH的分泌。与单独使用GnRH相比，仅0.1 nM（P = 0.06）和100 nM（P < 0.001）的食欲素 - B与1000 nM的GnRH联合使用可增加LH的分泌。与单独使用GRF相比，所有剂量的食欲素 - B与1000 nM GRF联合使用均抑制了（P < 0.0001）GH的分泌，而与单独使用GRF相比，仅0.1 nM的食欲素 - B与10 nM GRF联合使用抑制了（P < 0.01）GH的分泌。这些结果表明，食欲素可能在垂体水平直接调节LH和GH的分泌。
