Immunodetection of NGF, trkA, p75 and Inhibin .ALPHA.-Subunit in Interstitial Cells of Golden Hamsters Treated with hCG

Abstract

Abstract. The aim of this study was to investigate the effect of luteinizing hormone (LH) surge on expression of nerve growth factor (NGF), trkA, p75 and inhibin α-subunit in ovarian interstitial cells of golden hamsters after human chorionic gonadotropin (hCG) treatment. NGF, two NGF receptors (trkA, p75) and inhibin α-subunit were immunolocalized by immunohistochemistry, and gonadotropins, steroid hormones and immunoreactive (ir-) inhibin concentrations were measured by radioimmunoassay. Stronger positive staining of NGF, trkA and p75 were found in interstitial cells at 6, 12 and 18 h after hCG injection in the treated group compared with the control groups. Inhibin α-subunit staining was found in interstitial cells at 12 and 18 h after hCG injection in the treatment group, but not in the control group. Plasma concentrations of progesterone increased significantly from 6 to 18 h after hCG treatment, whereas plasma concentrations of estradiol-17β significantly decreased compared with the control group. An increased plasma concentration of FSH and decreased concentrations of ir-inhibin from 6 to 18 h after hCG treatment verified the negative relationship. There were no significant changes in the concentrations of LH in the hCG-treated group. In contrast, the typical preovulatory LH surge was found at 1700 h on day 4 (proestrus) in the control group. These results suggested that LH surge can induce expression of NGF, trkA, p75 and inhibin α-subunit in ovarian interstitial cells and that NGF, trkA, p75 and inhibin α-subunit may have a paracrine or autocrine role in modulation of ovarian interstitial cell function in golden hamsters. Key words: Golden hamster, Inhibin α-subunit, Interstitial cell, Nerve growth factor (NGF), p75 and trkA (J. Reprod. Dev. 55: [622][623][624][625][626][627][628] 2009) erve growth factor (NGF) belongs to a family of related proteins required for survival, maintenance and development of discrete neuronal populations in the central and peripheral nervous systems [1][2][3]. The effect of NGF has been shown to be mediated through a specific high-affinity membrane receptor, tyrosine kinase A (trkA), that is responsible for NGF's biological activities [4,5]. Furthermore, the effect of NGF is also mediated via low affinity p75 receptor, which is also a receptor of other neurotropins [6]. It is now well known that the mammalian ovary not only contains four of the known neurotropins [7][8][9][10][11][12], but also expresses the receptors for each of them [13,14]. Previous papers have indicated that NGF and its receptors play a critical role in the development of mammalian ovary, oogenesis and folliculogenesis [15][16][17][18][19][20][21]. Inhibin and activins are dimeric glycoproteins formed by two of three different subunits (α, βA and βB). Inhibins consist of either of the β-subunits dimerized with a common α-subunit (α:βA and α:βB; inhibin A and inhibin B, respectively). Activins are dimers of β-subunits (βA:βA, βA:βB and βB:βB; activin A, activin AB and activin B, respectively). Inhibin/...

The roles of glial cell line-derived neurotrophic factor, brain-derived neurotrophic factor and nerve growth factor during the final stage of folliculogenesis: a focus on oocyte maturation

“…The notion that gonadotrophins influence the expression of neurotrophins is also supported by the finding that NGF follicular fluid concentrations increased dramatically in ovine large, antral follicles in response to gonadotrophin stimulation (Barboni et al 2002) and in golden hamsters, the LH surge induced NGF, NTRK1 and NGFR protein expression in ovarian interstitial cells (Weng et al 2009). Furthermore, BDNF secretion by cumulus and granulosa cells was increased in women undergoing IVF in response to treatment with LH, human chorionic gonadotrophin (hCG) or menopausal urinary gonadotrophin (Feng et al 2003), and a recent study conducted by Zhao et al (2011) demonstrated that both GDNF and BDNF mRNA levels were slightly increased following FSH treatment of unstimulated human granulosa cells derived from women undergoing IVM (Zhao et al 2011).…”

Seasonal changes in expression of nerve growth factor and its receptors TrkA and p75 in the ovary of wild ground squirrel (Citellus dauricus Brandt)

“…These results were similar to those found in golden hamsters and pigs. Previous studies in golden hamster have suggested that LH surge may be an important factor for inducing the expression of NGF, TrkA, p75 in ovarian tissues periodically [16,18]. In pig ovary, the increase in expression of NGF and TrkA in large follicles found on day 20 may also result from an LH effect [35].…”

“…These results implied that NGF may act indirectly in follicular development through the production of biologically active FSHR [13]. In golden hamsters, as one member of TGFβ superfamily, inhibin α-subunit might works in concert with NGF and its receptors to act on LH/hCG receptor expression in ovarian interstitial cells and associated with the ovulatory process [18]. Also, our previous studies showed that inhibin/activin subunits (α, β(A) and β(B)) were present in granulosa cells, theca cells of antral follicles and interstitial cells in the breeding season ovary of wild ground squirrel, following ovulation, the corpora lutea become a major site of inhibin/activin synthesis [29].…”

“…It is now well known that NGF and its receptors are expressed in the mammalian ovary, including women [12-14], rats [14,15], golden hamsters [16-18], cows [19], sheep [20] and Shiba goats [21]. More and more evidences have indicated that NGF signaling plays a critical role in the development of mammalian ovary, oogenesis and folliculogensis [22-24], in an auto- and/or paracrine manner.…”

Testicular expression of NGF, TrkA and p75 during seasonal spermatogenesis of the wild ground squirrel (Citellus dauricus Brandt)

“… 4-6 In recent years, the studies of NGF and its receptors in reproductive system largely focus on the immunolocalization and expression of NGF system in reproductive organs, 7 , 8 the functional role of NGF system in the follicular development 9 , 10 and in spermatogenesis. 11-12 The studied species range from experimental models, such as rat, 7 , 8 , 11 mouse 12 and golden hamster, 13 , 14 to primate 15 and human. 16 , 17 Our previous results indicated that NGF and its receptors may be involved in the regulation of seasonal changes in the ovarian and uterine functions of wild female ground squirrels.…”