Nielsen M O, Fleet I R, Jakobsen K, Heap R B
Department of Anatomy and Physiology, Royal Veterinary and Agricultural University, Frederiksberg, Denmark.
J Endocrinol. 1995 Jun;145(3):585-91. doi: 10.1677/joe.0.1450585.
Mammary blood flow (MBF) and milk yield are closely related in dairy ruminants, but little is known about the regulation of MBF in vivo. The local effects on MBF of injections or continuous infusions into the mammary artery of prostaglandins (PG) or indomethacin (an inhibitor of prostaglandins) respectively, were investigated in surgically prepared conscious goats. Prostacyclin (PGI2) was found to be a potent stimulator of MBF which increased linearly over the dose range 50-1000 ng. PGE2 was almost as potent as PGI2 at low doses, but tachyphylaxis occurred at doses at and above 100 ng. The response to repeated injections of PGE2 quickly declined depending on the dose. PGF2 alpha had no effect on MBF. During infusion of indomethacin into the mammary artery MBF was reduced markedly, showing that endogenous mammary prostaglandins are involved in the regulation of vasodilatation. The results indicate that PGI2 (and to a lesser extent PGE2) has an important role in the local regulation of vascular tone in the mammary gland.
在反刍动物奶牛中，乳腺血流量（MBF）与产奶量密切相关，但关于体内MBF的调节机制却知之甚少。分别向手术制备的清醒山羊的乳腺动脉注射或持续输注前列腺素（PG）或吲哚美辛（一种前列腺素抑制剂），研究其对MBF的局部影响。发现前列环素（PGI2）是MBF的有效刺激剂，在50 - 1000 ng的剂量范围内呈线性增加。低剂量时PGE2的效力几乎与PGI2相同，但在100 ng及以上剂量时出现快速耐受。对重复注射PGE2的反应根据剂量迅速下降。PGF2α对MBF没有影响。向乳腺动脉输注吲哚美辛期间，MBF显著降低，表明内源性乳腺前列腺素参与血管舒张的调节。结果表明，PGI2（以及程度较轻的PGE2）在乳腺血管张力的局部调节中起重要作用。
