Epidermal growth factor in small antral ovarian follicles of pregnant women

Abstract

Levels of epidermal growth factor (EGF) and steroids were measured by radioimmunoassay in follicular fluid (FF) aspirated from 114 small antral follicles with diameters from 1 to 6 mm and in serum from 19 women undergoing Caesarean section at term. Concentrations of EGF in FF were inversely and significantly correlated to follicular size, being 4.7 +/- 0.4 (mean +/- S.E.M.) nmol/l in follicles of 1-2 mm in diameter and declining to 2.2 +/- 0.2 and 1.4 +/- 0.2 nmol/l in follicles of 3-4 mm and 5-6 mm in diameter respectively. The mean +/- S.E.M. concentration of EGF in serum (0.7 +/- 0.03 nmol/l) was significantly lower than that in FF. Levels of EGF, progesterone and oestradiol in FF were not significantly correlated to one another. In contrast to EGF, levels of progesterone and oestradiol in FF did not vary significantly with follicular diameter in these small follicles. On the basis of these results we suggest that EGF is synthesized in small human antral follicles, and that EGF stimulates granulosa cell proliferation and follicle growth up to 6 mm in diameter. Furthermore, the high intrafollicular levels of EGF may protect the small follicles against untimely effects of high levels of FSH, for instance during the mid-cycle surge of gonadotrophins. It is concluded that EGF plays an important role as an autocrine and/or paracrine regulator of development of small antral follicles in women.

Epidermal Growth Factor-Mediated Inhibition of Follicle-Stimulating Hormone-Stimulated StAR Gene Expression in Porcine Granulosa Cells Is Associated with Reduced Histone H3 Acetylation1

“…Preliminary studies were performed to determine the FSH and EGF concentrations and the time needed to observe an effect on StAR mRNA accumulation. Follicular fluid concentrations of EGF in different species have been reported to range from the low picograms per milliliter up to approximately 30 ng/ml [36,37]. Our preliminary studies revealed 10 ng/ml EGF was the lowest dose exhibiting statistically significant inhibition of StAR mRNA in combination with FSH and it was also a maximal dose.…”

Bovine Blastocyst Development after in Vitro Maturation in a Defined Medium with Epidermal Growth Factor and Low Concentrations of Gonadotropins1

“…An EGF-like substance has been shown to be secreted by rat ovarian thecal/ interstitial cells [13], and EGF has also been found in both pig (13.6 ng/ml) [6] and human (1.56-3.3 ng/ml) [29] follicular fluids. Other reports [7,30] have shown follicular fluid levels of EGF in women to range from 0.60 to 31.3 ng/ml. Additionally, EGF has been found to stimulate proliferative effects (increased [ 3 H]thymidine incorporation) in granulosa cells while attenuating FSH-induced differentiating functions; i.e., EGF decreases estrogen secretion by granulosa cells and inhibits the increase in FSH-induced LH receptors [11].…”

“…Serum is a highly complex combination of components including proteins, fatty acids, vitamins, trace elements, hormones, and growth factors. Thus, EGF in serum [6,7,45] is possibly one of the undetermined components contributing to enhanced oocyte maturation.…”

“…Fertilization rates (as reflected by the proportion of oocytes cleaved per oocytes inseminated) and development (as reflected by the proportions of oocytes matured and fertilized in vitro that reached 4-8-cell and 8-16-cell stages in culture) were enhanced by the addition of proestrous [3] or estrous [4,5] cow sera to media employed for IVM. Sera contain many components, including hormones, trace nutrients, and growth factors such as epidermal growth factor (EGF); in swine, reported serum EGF levels are 8 ng/ml [6] and in humans, 1.20-3.75 ng/ml [7]. During IVM these components may be responsible for subsequent enhanced viability of bovine oocytes.…”

Modulatory Role of Epidermal Growth Factor in Follicle-Stimulating Hormone-lnduced DNA Synthesis in Cultured Rat Granulosa Cells.

“…Among various polypeptide growth factors, epidermal growth factor (EGF) is detected in porcine [1] and human follicular fluid [2] and shown to be synthesized by thecal/ interstitial cells [3]. In addition, granulosa cells possess the receptor for EGF in several species [4][5][6][7].…”