Hu S Q, Zadworny D
Department of Animal Science, McGill University, Macdonald Campus, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada.
Department of Animal Science, McGill University, Macdonald Campus, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada.
Domest Anim Endocrinol. 2017 Oct;61:27-38. doi: 10.1016/j.domaniend.2017.05.002. Epub 2017 May 10.
In galliformes, the circulating isoform of prolactin (PRL) significantly changes during different reproductive states. However, the role of the major isoform (glycosylated PRL [G-PRL]) in ovarian steroidogenesis is unknown. The present study aimed to compare the effects of nonglycosylated (NG-) and G-PRL on basal and gonadotropin-stimulated estradiol (E) and progesterone (P) production in granulosa cells or follicular walls of chicken of different size class follicles. In the initial experiment, granulosa cells of preovulatory F3-F1 and prehierarchical 6- to 8-mm follicles were incubated for 24 h with different concentrations of NG- or G-PRL (0, 1, 10, 100, or 1,000 ng/mL). In the subsequent experiments, these categorized granulosa cells and follicular walls of prehierarchical 4-6, 2-4, and <2-mm follicles were incubated for 24 h in the absence and presence of 10-ng/mL FSH or LH, or in combination with different concentrations of NG- or G-PRL (10, 100, or 1,000 ng/mL). We observed that lower levels of NG-PRL induced (P < 0.05) E and P secretion in granulosa cells of either preovulatory or prehierarchical follicles, but at higher levels, this effect was reduced. In contrast, G-PRL promoted (P < 0.05) basal E and P secretion in preovulatory granulosa cells but was inhibitory (P < 0.05) in prehierarchical granulosa cells. Results obtained by real-time quantitative PCR (qPCR) demonstrated that these effects were mediated through modulation of the expression of StAR, CYP11A1, CYP19A1, and 3β-HSD. Furthermore, G-PRL was less potent than NG-PRL in inhibiting FSH- or LH-stimulated E and P production in granulosa cells of preovulatory follicles, whereas NG-PRL enhanced (P < 0.05) but G-PRL reduced (P < 0.05) FSH-induced P production in those of prehierarchical follicles. In follicular walls from each group of prehierarchical 4-6, 2-4, and <2-mm follicles, NG- and G-PRL had both stimulatory and inhibitory influences on the actions of FSH on E and P secretion, but both suppressed (P < 0.05) LH-induced E and P secretion except for the synergistic effects of LH and G-PRL on P secretion by follicular walls of the follicles of 4-6 mm. Taken together, these results suggest that both NG- and G-PRL are biologically active in regulating basal and gonadotropin-stimulated E and P production in chicken ovarian follicles. However, their effects are different depending on the concentration, the type of gonadotropin (FSH or LH), and the stage of follicle development.
在鸡形目动物中，催乳素（PRL）的循环异构体在不同生殖状态下会发生显著变化。然而，主要异构体（糖基化催乳素[G-PRL]）在卵巢类固醇生成中的作用尚不清楚。本研究旨在比较非糖基化（NG-）和G-PRL对不同大小等级卵泡的鸡颗粒细胞或卵泡壁中基础和促性腺激素刺激的雌二醇（E）和孕酮（P）产生的影响。在初始实验中，将排卵前F3-F1卵泡和等级前6至8毫米卵泡的颗粒细胞与不同浓度的NG-或G-PRL（0、1、10、100或1000 ng/mL）孵育24小时。在随后的实验中，将这些分类的颗粒细胞和等级前4-6、2-4和<2毫米卵泡的卵泡壁在不存在和存在10 ng/mL促卵泡激素（FSH）或促黄体生成素（LH）的情况下，或与不同浓度的NG-或G-PRL（10、100或1000 ng/mL）组合孵育24小时。我们观察到，较低水平的NG-PRL诱导（P < 0.05）排卵前或等级前卵泡颗粒细胞中E和P的分泌，但在较高水平时，这种作用会减弱。相比之下，G-PRL促进（P < 0.05）排卵前颗粒细胞中基础E和P的分泌，但对等级前颗粒细胞具有抑制作用（P < 0.05）。实时定量PCR（qPCR）获得的结果表明，这些作用是通过调节类固醇生成急性调节蛋白（StAR）、细胞色素P450侧链裂解酶（CYP11A1）、芳香化酶（CYP19A1）和3β-羟基类固醇脱氢酶（3β-HSD）的表达来介导的。此外，在抑制排卵前卵泡颗粒细胞中FSH或LH刺激的E和P产生方面，G-PRL的效力低于NG-PRL，而在等级前卵泡颗粒细胞中，NG-PRL增强（P < 0.05）但G-PRL降低（P < 0.05）FSH诱导的P产生。在每组等级前4-6、2-4和<2毫米卵泡的卵泡壁中，NG-和G-PRL对FSH对E和P分泌的作用既有刺激作用也有抑制作用，但除了LH和G-PRL对4-6毫米卵泡卵泡壁P分泌的协同作用外，两者均抑制（P < 0.05）LH诱导的E和P分泌。综上所述，这些结果表明，NG-和G-PRL在调节鸡卵巢卵泡中基础和促性腺激素刺激的E和P产生方面均具有生物学活性。然而，它们的作用因浓度、促性腺激素类型（FSH或LH）以及卵泡发育阶段而异。
