Expression and localization of growth hormone and its receptors in the chicken ovary during sexual maturation

Abstract

Roles of pituitary growth hormone (GH) in female reproduction are well established. Autocrine and/or paracrine actions of GH in the mammalian ovary have additionally been proposed, although whether the ovary is an extra-pituitary site of GH expression in the laying hen is uncertain. This possibility has therefore been assessed in the ovaries of Hy-Line hens before (between 10-16 weeks of age) and after (week 17) the onset of egg laying. Reverse transcription/polymerase chain reaction (RT-PCR) analysis has consistently detected a full-length (690 bp) pituitary GH cDNA in ovarian stroma from 10 weeks of age, although GH expression is far lower than that in the pituitary gland or hypothalamus. GH mRNA is also present in small (>1-4 mm diameter) follicles after their ontogenetic appearance at 14 weeks of age and in all other developing follicles after 16 weeks of age (>4-30 mm diameter). Immunoreactivity for GH is similarly present in the ovarian stroma from 10 weeks of age and in small (<4 mm diameter) and large (>4-30 mm) follicles from 14 and 16 weeks of age, respectively. The relative intensity of GH staining in the ovarian follicles is consistently greater in the granulosa cells than in the thecal cells and is comparable with that in the follicular epithelium. A 321-bp fragment of GH receptor (GHR) cDNA, coding for the intracellular domain of the receptor, has also been detected by RT-PCR in the ovary and is present in stromal tissue by 10 weeks of age, in small follicles (<4 mm diameter) by 14 weeks of age, and in larger follicles (>4-30 mm diameter) from 16 weeks. GHR immunoreactivity has similarly been detected, like GH, in the developing ovary and in all follicles and is more intense in granulosa cells than in the theca interna or externa. The expression and location of the GH gene therefore parallels that of the GHR gene during ovarian development in the laying hen, as does the appearance of GH and GHR immunoreactivity. These results support the possibility that GH has autocrine and/or paracrine actions in ovarian function prior to and after the onset of lay in hens.

Effect of growth hormone on steroid content, proliferation and apoptosis in the chicken ovary during sexual maturation

“…The period of several weeks before puberty is characterized by the rapid growth of the ovary; this is regulated predominantly by gonadotrophins and steroid hormones (Senior 1974;Williams and Sharp 1977;Sechman et al 2000;Paczoska-Eliasiewicz et al 2006a). The changes in GH and GHR expression in the ovary at this time (Hrabia et al 2008) and the increase in plasma GH at the time of maturation (Williams et al 1986) suggest the participation of GH in ovarian steroidogenesis. Thus, first, the involvement of GH in steroidogenesis has been demonstrated in the current study.…”

“…The presented data do not make clear whether injected cGH acts both centrally and/or peripherally to affect steroidogenesis. The presence of GHR at all sites of the chicken hypothalamic-pituitary-ovarian axis makes such a possibility feasible (Fraser et al 1990;Hrabia et al 2008). Moreover, Fig.…”

“…GH receptors in the granulosa and theca layers of preovulatory follicles (Lebedeva et al 2004) and GH receptor (GHR) mRNA in the ovaries of growing broiler breeder chickens (Heck et al 2003) have also been reported. Although our recent study (Hrabia et al 2008) has shown mRNA expression and protein localization of GH and GHR in each compartment of the hen ovary prior to and after the onset of laying, thereby suggesting a local role of GH in ovarian function, the role of GH in the chicken ovary is unknown. Therefore, in the present study, we have studied the effect of GH on the steroidogenic activity of the domestic hen ovary during sexual maturation.…”

“…Control of its activity is multihormonal and includes gonadotrophins and locally produced regulators. One suggested ovarian function regulator is growth hormone (GH; Heck et al 2003;Lebedeva et al 2004;Hrabia et al 2008).…”

The Associations of GH and GHR Genes with Carcass Components in Indonesian Kampung and Broiler Chicken Cross

“…The chicken growth hormone is widely known as a major hormone that acts directly on chicken development and metabolism (Kim, 2010) and relates to egg production (Su et al, 2014;Vu & Ngu, 2016). GH regulates a variety of physiological functions such as growth, body composition, egg production, aging, reproduction, sexual maturation, and functionality of the central nervous system (Gosney et al, 2012;Hrabia et al, 2008;Hull & Harvey, 2014;Stephen et al, 2001). The GH/ IGF-1 signaling pathway is also believed to be capable of promoting growth of selected types of cancer (Kopchick et al, 2014).…”