Armstrong D T, Weiss T J, Selstam G, Seamark R F
J Reprod Fertil Suppl. 1981;30:143-54.
Studies of isolated cell types from sheep follicles revealed several functional changes which occur during follicular maturation. Cyclic AMP production by granulosa cells from the smallest follicles studied (1-3 mm diameter) was stimulated by FSH but not by hCG, suggesting functional FSH receptors at this early stage of differentiation. Medium-sized follicles (4-6 mm) responded to both FSH and hCG. Granulosa cells were unable to synthesize androgens, but readily converted exogenous testosterone to oestradiol-17 beta. This conversion occurred to a limited extent in the cells from the smallest follicles, but was much greater in medium and large (greater than 6 mm) follicles. Oestradiol production by theca preparations from small follicles was barely detectable, but increased markedly with increasing follicle size. Androgen (androstenedione and testosterone) production by theca preparations was stimulated by hCG. This stimulation was short-lived, and levels declined to below control values after 6 h of culture. This decline could not be prevented by addition of cyclic AMP. The presence of granulosa cells with thecal preparations (i.e. follicle wall tissue) enhanced production of androgen by the theca, the effect being more marked for testosterone than for androstenedione. In-vivo studies in which granulosa cells and follicular fluid were removed during the preovulatory period suggested that granulosa cells and/or follicular fluid contributed to the oestradiol secreted into the ovarian vein during this period, but did not exclude a significant contribution by the theca as well.
对绵羊卵泡中分离出的细胞类型进行的研究揭示了卵泡成熟过程中发生的几种功能变化。研究的最小卵泡（直径1 - 3毫米）的颗粒细胞产生的环磷酸腺苷（cAMP）受促卵泡激素（FSH）刺激，但不受人绒毛膜促性腺激素（hCG）刺激，这表明在分化的早期阶段存在功能性FSH受体。中等大小的卵泡（4 - 6毫米）对FSH和hCG均有反应。颗粒细胞无法合成雄激素，但能轻易地将外源性睾酮转化为雌二醇-17β。这种转化在最小卵泡的细胞中程度有限，但在中等大小和大卵泡（大于6毫米）中则更为显著。小卵泡的卵泡膜制剂产生的雌二醇几乎检测不到，但随着卵泡大小增加而显著增加。卵泡膜制剂产生雄激素（雄烯二酮和睾酮）受hCG刺激。这种刺激是短暂的，培养6小时后水平降至对照值以下。添加环磷酸腺苷无法阻止这种下降。颗粒细胞与卵泡膜制剂（即卵泡壁组织）共同存在时可增强卵泡膜产生雄激素的能力，对睾酮的作用比对雄烯二酮更为明显。排卵前期去除颗粒细胞和卵泡液的体内研究表明，颗粒细胞和/或卵泡液在此期间对分泌到卵巢静脉中的雌二醇有贡献，但并不排除卵泡膜也有显著贡献。
