Paavola L G, Boyd C O
Anat Rec. 1981 Sep;201(1):127-40. doi: 10.1002/ar.1092010115.
Secretory granules, which are released by exocytosis and are speculated to contain progesterone, have been described in luteal cells of sheep and other large domestic animals. These granules are small and densely staining. Gemmell and Stacy ('79) suggested that luteal cells of guinea pigs also contain secretory granules, although they could not document exocytosis of granule content at the fine structural level. For the present study, quantitative methods were used to reexamine the possibility that luteal cells of guinea pigs possess secretory granules. Ovaries of guinea pigs were fixed in situ by vascular perfusion at the time of maximum progesterone secretion, when such granules would be most abundant, as well as other stages. Two types of granules that might be confused with secretory granules are microperoxisomes and lysosomes. Therefore, slices of perfusion-fixed corpora lutea were incubated for the fine structural localization of a peroxisomal enzyme, catalase, or for the lysosomal enzymes, acid phosphatase (ACPase) and arylsulfatase. Other tissue was prepared for conventional electron microscopy. Granule types were classified on the basis of size, morphology, and enzyme content. Quantitation of granule types was carried out on both cytochemically reacted and conventionally prepared luteal tissue. More than 5500 microperoxisomes, 2800 lysosomes, and 1100 multivesicular bodies (MVBs) were tabulated. The results indicate that luteal cells of guinea pigs have three main types of granules: 1) Microperoxisomes, about 0.2 micrometer in diameter and containing catalase; 2) lysosomes, about 0.5 micrometer in diameter and positive for ACPase and arylsulfatase; and 3) MVBs, about 0.4 micrometer in diameter and containing small vesicles. At the time of peak steroid secretion during pregnancy and the estrous cycle, the granule population in luteal cells of guinea pigs consists of 73-80% microperoxisomes, 13-17% lysosomes, and 7-9% MVBs. These proportions are similar in tissue reacted for cytochemistry and tissue prepared by conventional means. Greater than 99% of the small 0.2-0.3 micrometer diameter granules in guinea pig luteal cells are catalase reactive. This finding eliminates from further consideration most of the prime candidates for secretory granules in these cells. Finally, neither a sequential appearance of granules nor exocytosis of secretory product was detected. Our data thus argue against the suggestion that luteal cells of guinea pig have secretory granules of the type observed in corpora lutea of large domestic animals.
分泌颗粒通过胞吐作用释放，据推测含有孕酮，已在绵羊和其他大型家畜的黄体细胞中有所描述。这些颗粒小且染色致密。杰梅尔和斯泰西（1979年）认为豚鼠的黄体细胞也含有分泌颗粒，尽管他们无法在精细结构水平上证实颗粒内容物的胞吐作用。在本研究中，采用定量方法重新审视豚鼠黄体细胞是否存在分泌颗粒的可能性。在孕酮分泌量最大时，即此类颗粒最丰富的时候，以及在其他阶段，通过血管灌注将豚鼠卵巢原位固定。可能与分泌颗粒混淆的两种颗粒是微过氧化物酶体和溶酶体。因此，对灌注固定的黄体切片进行孵育，以对过氧化物酶体酶过氧化氢酶或溶酶体酶酸性磷酸酶（ACPase）和芳基硫酸酯酶进行精细结构定位。其他组织则用于常规电子显微镜检查。根据大小、形态和酶含量对颗粒类型进行分类。对经细胞化学反应和常规制备的黄体组织中的颗粒类型进行定量分析。统计了超过5500个微过氧化物酶体、2800个溶酶体和1100个多囊泡体（MVB）。结果表明，豚鼠黄体细胞有三种主要类型的颗粒：1）微过氧化物酶体，直径约0.2微米，含有过氧化氢酶；2）溶酶体，直径约0.5微米，ACPase和芳基硫酸酯酶呈阳性；3）多囊泡体，直径约0.4微米，含有小泡。在怀孕和发情周期的类固醇分泌高峰期，豚鼠黄体细胞中的颗粒群体由73 - 80%的微过氧化物酶体、13 - 17%的溶酶体和7 - 9%的多囊泡体组成。在经细胞化学反应的组织和通过常规方法制备的组织中，这些比例相似。豚鼠黄体细胞中直径为0.2 - 0.3微米的小颗粒中，超过99%对过氧化氢酶有反应。这一发现排除了这些细胞中大多数作为分泌颗粒的主要候选者。最后，未检测到颗粒的相继出现或分泌产物的胞吐作用。因此，我们的数据反驳了豚鼠黄体细胞具有在大型家畜黄体中观察到的那种分泌颗粒的观点。
