Inhibin-A and Inhibin-B in stallions: Seasonal changes and changes after down-regulation of the hypothalamic-pituitary-gonadal axis.

08:00 EDT 27th September 2018 | BioPortfolio

Summary of "Inhibin-A and Inhibin-B in stallions: Seasonal changes and changes after down-regulation of the hypothalamic-pituitary-gonadal axis."

The biological function of inhibin is mediated by two heterodimers, inhibin-A and inhibin-B. The relative importance of inhibin-A and -B in male reproductive function varies considerably across species with inhibin-B predominating in many species, whereas inhibin-A appears relatively more important in rams. Research reported to date in stallions has examined total or immunoreactive (ir) inhibin which does not distinguish the two heterodimers. Therefore, the objective of this study was to characterize changes in inhibin-A and inhibin-B concentrations in stallions: 1) across season for a period of one year, and 2) after downregulation of the hypothalamic-pituitary-gonadal (HPG) axis. In Study one, serum samples were obtained monthly from five stallions for a period of one year. Serum concentrations of inhibin-A, inhibin-B, testosterone and estrone sulfate were determined by ELISA. In Study two, stallions were treated with the GnRH antagonist, acyline (n = 4; 330 mg/kg acyline IM) or vehicle control (n = 4; vehicle alone) every five days for 50 days. Plasma concentrations of inhibin-A and -B were determined by ELISA at Days 0, 6, 12, 22, 37, 59, 80, 87 and 104 after initiation of acyline treatment. Testis volume was determined by ultrasonography at weekly intervals. In Study 1, both inhibin-A and inhibin-B showed seasonal changes in concentration with highest concentrations in increasing day length and lowest concentrations in short day lengths. Inhibin-B (overall mean 107.8 ± 4.1 pg/mL) was present at 4.7-fold higher concentrations in serum than inhibin-A (overall mean 23.0 ± 0.7 pg/mL). In Study 2, plasma concentrations of inhibin-B but not inhibin-A were significantly downregulated by administration of the GnRH antagonist, acyline. When the HPG axis was downregulated by acyline, testis volume was strongly correlated with inhibin-B (r = 0.73; P < 0.05) but not inhibin-A (r = 0.22; P = 0.20). In summary, inhibin-B appears to be the predominant form of inhibin in the stallion which undergoes seasonal regulation along with other reproductive parameters and is co-regulated with other endocrine parameters of the HPG axis.


Journal Details

This article was published in the following journal.

Name: Theriogenology
ISSN: 1879-3231
Pages: 108-115


DeepDyve research library

PubMed Articles [785 Associated PubMed Articles listed on BioPortfolio]

CORRIGENDUM FOR "Betaglycan (TGFBR3) Functions as an Inhibin A, but Not Inhibin B, Coreceptor in Pituitary Gonadotrope Cells in Mice".

Cumulin and FSH cooperate to regulate inhibin B and activin B production by human granulosa-lutein cells in vitro.

The oocyte-secreted factors bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9) interact functionally and it is hypothesised that this interaction may be mediated by forma...

The role of active immunization against inhibin α-subunit on testicular development, testosterone concentration and relevant genes expressions in testis, hypothalamus and pituitary glands in Yangzhou goose ganders.

The present study was designed to investigate the potential role of immunization against inhibin on testicular development, plasma testosterone concentration and expression of relevant genes in hypoth...

Inhibin B level helps evaluate the testicular function of prepubertal patients with varicocele.

To investigate the role of the serum inhibin B (INHB) level in evaluating the testicular function of the prepubertal patient with varicocele (VC) after high ligation of the spermatic vein (HLSV).

Serum inhibin B concentration as a predictor of age at first menstruation in girls with idiopathic central precocious puberty.

To compare the serum inhibin B, anti-Müllerian hormone (AMH) and leptin concentrations in girls with idiopathic central precocious puberty (CPP) to their concomitant characteristics and evaluate the ...

Clinical Trials [407 Associated Clinical Trials listed on BioPortfolio]

Role of Inhibin A as Biomarker for Ovarian Response for IVF Treatment

To evaluate the role of Inhibin A as bio marker for the number of mature oocytes, compared to Estradiol

Human Chorionic Gonadotrophin in an Antagonist Protocol

A novel gonadotropin protocol for ovarian stimulation adds low-dose hCG (50- 200 IU) as a source of LH (luteinizing hormone) in the late follicular phase . This regimen reduces the numbe...

Blood Spot Self-administered Test and Assay

The current study will compare hormone levels of AMH, FSH and inhibin B in blood specimens collected by venipuncture and fingerstick in a sample of pre-menopausal women ages 18-45 years wi...

Time to Conceive: A Study Focusing on Fertility

The purpose of this research study is to learn a way to measure a person's fertility. After 1 year of trying, 1 out of every 7 women will not be pregnant. This is called infertility. This...

Human Chorionic Gonadotropin (hCG) Test: A Novel Method to Evaluate the Ovarian Reserve

In an era of delayed fertility plans, there is an increasing need for a reliable method to predict ovarian reserve and responsiveness. The current tests include serum FSH, Inhibin B, Mulle...

Medical and Biotech [MESH] Definitions

Glycoproteins that inhibit pituitary FOLLICLE STIMULATING HORMONE secretion. Inhibins are secreted by the Sertoli cells of the testes, the granulosa cells of the ovarian follicles, the placenta, and other tissues. Inhibins and ACTIVINS are modulators of FOLLICLE STIMULATING HORMONE secretions; both groups belong to the TGF-beta superfamily, as the TRANSFORMING GROWTH FACTOR BETA. Inhibins consist of a disulfide-linked heterodimer with a unique alpha linked to either a beta A or a beta B subunit to form inhibin A or inhibin B, respectively

Activins are produced in the pituitary, gonads, and other tissues. By acting locally, they stimulate pituitary FSH secretion and have diverse effects on cell differentiation and embryonic development. Activins are glycoproteins that are hetero- or homodimers of INHIBIN-BETA SUBUNITS.

They are glycopeptides and subunits in INHIBINS and ACTIVINS. Inhibins and activins belong to the transforming growth factor beta superfamily.

A neoplasm composed entirely of GRANULOSA CELLS, occurring mostly in the OVARY. In the adult form, it may contain some THECA CELLS. This tumor often produces ESTRADIOL and INHIBIN. The excess estrogen exposure can lead to other malignancies in women and PRECOCIOUS PUBERTY in girls. In rare cases, granulosa cell tumors have been identified in the TESTES.

A broadly distributed protein that binds directly to ACTIVINS. It functions as an activin antagonist, inhibits FOLLICLE STIMULATING HORMONE secretion, regulates CELL DIFFERENTIATION, and plays an important role in embryogenesis. Follistatin is a single glycosylated polypeptide chain of approximately 37-kDa and is not a member of the inhibin family (INHIBINS). Follistatin also binds and neutralizes many members of the TRANSFORMING GROWTH FACTOR BETA family.

Quick Search


DeepDyve research library

Relevant Topics

Diabetes Diabetes Endocrine Disorders Obesity Oxycontin Renal Disease Thyroid Disorders Endocrinology is the study of the endocrine glands and the hormones that they secrete (Oxford Medical Dictionary). There are several g...

Biological Therapy
Biological therapy involves the use of living organisms, substances derived from living organisms, or laboratory-produced versions of such substances to treat disease. Some biological therapies for cancer use vaccines or bacteria to stimulate the body&rs...

Searches Linking to this Article