【摘要】 ２ｍｉｎ脉冲式１０ｎｍｏｌ鲑ＧｎＲＨ高效类似物ｓＧｎＲＨ－Ａ（Ａｒｇ￣６Ｔｒｐ￣７Ｌｅｕ￣８ｐｒｏ￣９ＮＥｔ－ＬＨＲＨ）刺激导致离体灌流培育的鲤脑垂体迅速产生显著的ＧｔＨ分泌峰，ＧｔＨ分泌在刺激后３０ｍｉｎ内恢复到基础水平。４ｈ１０ｎｍｏｌ／ＬｓＧｎＲＨ－Ａ持续性刺激导致灌流培育的鲤脑垂体ＧｔＨ分泌出现脱敏反应，整个过程包括刺激后迅速的ＧｔＨ分泌峰相和随后持续低水平的ＧｔＨ分泌相。无Ｃａ￣（＋＋）的灌流液或用ＥＧＴＡ赘合了灌流液中的Ｃａ￣（＋＋）对灌流培育的鲤脑垂体基础ＧｔＨ分泌没有影响，但导致胞垂体对２ｍｉｎ１０ｎｍｏｌ／ＬｓＧｎＲＨ－Ａ刺激的ＧｔＨ分泌反应显著降低以及脑垂体对持续性１０ｎｍｏｌ／ＬｓＧｎＲＨ－Ａ刺激的ＧｔＨ分泌的脱敏反应消失，而仅出现低水平的ＧｔＨ分泌反应。更多还原

【Abstract】 Two-min pulse of 10nmol/L sGnRH-A(Arg￣6Trp￣7Leu￣8pro￣9NEt-LHRH)stimula-ted a rapid and significant release of GtH from perifused pituitary fragments ofcommon carp.The GtH level then decreased and to its basal level within 30-minafter the introduction of the sGnRH-Apulse. The continuous exposure of perifusedpituitary fragments to 10nmol/L sGnRH-A for 4hrs resulted in desensitization in-cluding two phases:an initial pcak phase of GtH release and a followed lowerlevel phase of GtH release. The perifusion of the pituitary fragments with Ca￣(++)freeHanks salt solution or the salt solution containing EGTA(1.25 and 5mmol/L)didnot influence the basal GtH release,but resulted in a significant decrease in GtHrelease if stimulated by 2-min pulses of 10nmol/L sGnRH-A and in disappearance ofdesensitization of GtH release which is induced by continuous administration ofof 10nmol/L sGnRH-A.更多还原