家蝇卵巢摄取卵黄蛋白的机理

在家蝇Ｍｕｓｃａ　ｄｏｍｅｓｔｉｃａ　ｖｉａｉｎａ的印黄发生过程中，卵母细胞摄取卵黄原蛋白与滤沟开放是相关的。观察不同发育时期的家蝇滤泡结果表明，在摄取活动最旺盛的时期也就是卵黄发生的顶盛时期，其滤泡开放程度最大，而在卵黄发生前期和后期基本上没有摄取活动，此时的滤泡上皮细胞间不开放。卵巢体外培养的激素处理表明，ＪＨ可以促进滤泡开放。家蝇卵巢微粒体制备物的Ｎａ＋－Ｋ＋ＡＴＰ酶活力在卵巢发育过程中存在着动态变化。羽化后２４小时时有一定的酶活性，随着卵黄发生的进行，酶活力逐渐增加，到现化４８小时时酶活力最高，然后又开始下降，到弱化７２小时时已经很小。羽化３２小时的家蝇点滴或注射ＪＨ之后，测得的卵巢微粒体制备物的Ｎａ＋－Ｋ＋ＡＴＰ酶活力比正常羽化３６小时的高，羽化率４４小时的家蝇点滴和注射ＪＨ之后，测得酶活力比正常羽化４８小时的低．羽化３６小时和４８小时的家蝇卵巢微粒体制备物与ＪＨ共同作用后，其Ｎａ＋－Ｋ＋ＡＴＰ酶的活力分别增加２．９５倍和３．５０倍，羽化４８小时的家蝇卵巢在含有ＪＨ的培养液中培养后，其匀浆液的酶活性为对照组的１．２６倍。由此我们可以推测在家蝇的卵黄发生过程中，ＪＨ通过促进滤泡开放和增加卵巢微粒体制

THE MECHANISM OF YOLK PROTEIN UPTAkE INHOUSEFLY OVARIES

sing a vital staining technique the difference of potency was observed in yolkdeposition into the oocytes during vitellogenesis of the housefly Musca domesticamacina. The potency of yolk deposition could be observed in vitellogenic follices,but not in prev and postvitellogenic follicles. The uptake of vitellogenin reachedmaximum during stage 6 of ovarian development (48 hours after adult eclosion)which was in coincidence with the high potency observed, while vitellogenin uptakeinto the ovary during the pre- and post-vitellogenic stages of oogenesis was hardlydetectable. The potency of yolk deposition was significantly increased when theovaries were incubated in the cultural medium containing JH III.The level of Na+--K+ ATPase activity in ovarian microsomal fractions rose andfell in concert with the vitellogenic stages of oocyte development. Our results showed that the enzymic activity in previtellogenic flies 24 flours after eclosion waslow; it rose and reached the peak in the ovaries of the flies 48 hours after eclosionand then decreased sharply to a very low level in the flies 72 hours after eclosion.When JH was injected into or topically applied on the body of the fly 32 hoursafter eclosion, the enzymic activity of microsomal fractions was found higher thanthat of the fly 36 hours after eclosion. However, when JH was injected into or topically applied on the body of the fly 44 hours after eclosion, the enzymic activitywas found lower than that of the fly 48 hours after eclosion. When JH was addedto a microsomal fraction prepared from ovaries 36 and 48 hours after eclsion, theenzymic activities were increased by 295 % and 350 %, respectively. When vitellogenicovaries were incubaled in the medium with the presence of JH (10 g/l), the enzymic activity increased by 1.26 fold in the homogenate.We infer from our results that JH is related to the potency of yolk depositionand increase of Na+--K+ ATPase activity so as to regulate the uptake of vitellogeninby oocytes.