Effect of follicle size on in vitro production of steroids and insulin-like growth factor (IGF)-I, IGF-II, and the IGF-binding proteins by equine ovarian granulosa cells
Effect of follicle size on in vitro production of steroids and insulin-like growth factor (IGF)-I, IGF-II, and the IGF-binding proteins by equine ovarian granulosa cells
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DOI：
10.1095/biolreprod66.6.1640
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发表时间：
2002-06-01
影响因子：
3.6
通讯作者：
Spicer, LJ
中科院分区：
文献类型：
--
作者：
Davidson, TR;Chamberlain, CS;Spicer, LJ
关于母马颗粒细胞类固醇合成和卵巢胰岛素样生长因子(IGF)系统的激素调节知之甚少。本研究的目的是，首先，确定雌二醇、胰岛素和/或FSH是否影响马颗粒细胞产生类固醇(实验1)；其次，IGF系统的组成部分是否由培养的马颗粒细胞产生；以及雌激素、胰岛素和/或FSH是否影响马颗粒细胞产生IGF和/或IGF结合蛋白(IGFBP)(实验2)。取周期母马(n=14)小卵泡(6~15 mm)、中卵泡(16~25 mm)和大卵泡(25~48 mm)的颗粒细胞，在含10%胎牛血清的培养液中培养2d，洗涤后在添加或不添加激素的无血清培养液中再培养2d。在实验1中，大卵泡颗粒细胞比中、小卵泡颗粒细胞产生更少的孕酮和更多的雌二醇(P<；0.05)。卵泡刺激素和胰岛素可抑制中、小卵泡颗粒细胞孕酮的生成(P<；0.05)，但对大卵泡颗粒细胞无抑制作用；胰岛素增加(P<；0.05)小卵泡和中卵泡颗粒细胞雌二醇的产生，但对大卵泡颗粒细胞没有影响。在实验2中，胰岛素抑制了所有卵泡大小的IGF-I的产生(P<；0.05)，但不受雌二醇或FSH的影响。中、大卵泡颗粒细胞分泌IGF-II高于小卵泡颗粒细胞(P<；0.05)。胰岛素和FSH抑制(P<；0.05)大、中卵泡颗粒细胞分泌IGF-II，但不抑制小卵泡颗粒细胞分泌IGF-II，雌二醇无此作用。马颗粒细胞仅产生IGFBP-2和IGFBP-5。大卵泡颗粒细胞产生的IGFBP-2比中、小卵泡少(P<；0.10)，而中卵泡颗粒细胞产生的IGFBP-5多(P<；0.05)。平均来看，雌二醇增加(P<；0.05)IGFBP-2的产生，FSH增加(P<；0.10)IGFBP-2和-5的产生，而胰岛素没有影响。这些结果表明，IGF-I、IGF-II、IGFBP-2和IGFBP-5是由马颗粒细胞产生的，胰岛素、FSH和雌二醇在马颗粒细胞的类固醇合成和IGF系统中起着调节作用。
Little is known regarding the hormonal regulation of granulosa cell steroidogenesis and the ovarian insulin-like growth factor (IGF) system in the mare. The objectives of this study were to determine, first, if estradiol, insulin, and/or FSH affect steroid production by equine granulosa cells (experiment 1) and, second, if the components of the IGF system are produced by equine granulosa cells in culture as well as whether estradiol, insulin, and/or FSH affects IGF and/or IGF-binding protein (IGFBP) production by equine granulosa cells (experiment 2). Granulosa cells from small (6-15 mm), medium (16-25 mm), and large (25-48 mm) follicles were collected from cyclic mares (n = 14), cultured for 2 days in medium containing 10% fetal calf serum, washed, and then treated for an additional 2 days in serum-free medium with or without added hormones. In experiment 1, large-follicle granulosa cells produced less progesterone and more estradiol than did medium- and/or small-follicle granulosa cells (P < 0.05). Progesterone production was inhibited (P < 0.05) by FSH and insulin in small- and medium- but not in large-follicle granulosa cells; estradiol was without effect. Insulin increased (P < 0.05) estradiol production in small- and medium-follicle granulosa cells but had no effect in large-follicle granulosa cells. In experiment 2, IGF-I production was inhibited (P < 0.05) by insulin across all follicle sizes but was not affected by estradiol or FSH. Granulosa cells of medium and large follicles produced more IGF-II than did granulosa cells of small follicles (P < 0.05). Insulin and FSH inhibited (P < 0.05) IGF-II production by granulosa cells of large and medium but not of small follicles; estradiol was without effect. Only IGFBP-2 and -5 were produced by equine granulosa cells. Production of IGFBP-2 was less (P < 0.10) in granulosa cells of large versus those of small and medium follicles, whereas medium-follicle granulosa cells produced more (P < 0.05) IGFBP-5 than did small- or large-follicle granulosa cells. Averaged across follicle sizes, estradiol increased (P < 0.05) IGFBP-2 production, FSH increased (P < 0.10) IGFBP-2 and -5 production, and insulin was without effect. These results indicate that IGF-I, IGF-II, IGFBP-2, and IGFBP-5 are produced by equine granulosa cells and that insulin, FSH, and estradiol play a role in the regulation of steroidogenesis and the IGF system of equine granulosa cells.