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Three experimental approaches were chosen to study the question if the progestin 17-hydroxy-20-dihydroprogesterone (1720OHP) is synthesised in testes of young Oncorhynchus mykiss, in which the absence of spermatozoa was verified histologically: first, in order to detect 20-hydroxysteroid dehydrogenase activity (20HSD), testes homogenates were incubated with 3H-labeled 17OHP.Metabolites were analysed by TLC, HPLC, and repeated crystallization to constant isotope ratios. One of the metabolites was identified as 1720OHP-3H, indicating that already immature testes contain 20HSD activity and are able to produce 20-reduced steroids. Second, 1720OHP was quantified by radioimmunoassay in incubates of testes fragments. The sensitivity of the gonads to gonadotropin II (GtH II) became evident when comparing incubations in the absence and presence of GtH II. Third, plasma levels of 1720OHP were significantly higher in animals injected with partially purified salmon gonadotropin, compared to controls. Thus, for the first time, it could be shown that 20HSD is present in testicular cells other than spermatozoa. Furthermore, 1720OHP is indeed secreted at a very early stage of testicular development; 1720OHP secretion is also responsive to GtH II. Future studies will have to show if the functions of this progestin include the stimulation of spermatogenesis. 相似文献
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大漠温室模糊控制系统设计 总被引：2，自引：2，他引：0
依托温度传感器Wzppt100、湿度传感器HS1101以及单片机MC68HC705C8等硬件,设计了针对中卫沙坡头地区果蔬温室的智能控制系统,在采集与处理温室温度、湿度和光照度等参数的基础上,采用模糊算法,实现对温室卷帘机、换气扇、供暖器和微管喷滴灌等系统的实时控制。 相似文献
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枸杞产业是宁夏的支柱产业之一,枸杞干果的制作一直采用烘干工艺,烘干果存在色泽黑红、果实干瘪和易吐糖霉变等缺点.为此,以MC68HC705C8单片机为核心,采用模糊控制技术,对枸杞鲜果采用真空仓冻干工艺,不仅克服了烘干果的不足,而且具有节能、高效和成品率高等特点. 相似文献
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刘贵斌 《大连水产学院学报》1998,13(1):54-57
本文介绍的预付费电子电度表是由美国Ｍｏｔｏｒｏｌａ公司生产的单片机ＭＣ６８ＨＣ７０５Ｌ１和外转电路组成的,该表降低了计算盲区,提高了电度表的精度,使用ＩＣ卡作为预付费的工具,给电业部门的现代化管理提供了必要的条件。 相似文献
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