Inhibin concentrations in mares with granulosa cell tumors.
Abstract: The hormone-producing equine granulosa cell tumor (GCT) may secrete high levels of inhibin. Measurement of inhibin concentrations may be useful in the diagnosis and conformation of mares with GCT. Inhibin may be measured using RIA, which recognizes dimeric alphabetaA-inhibin as well as the monomeric (free) inhibin alpha-subunit, or using a two-site immunoradiometric assay (IRMA) specific for alphabetaA-inhibin. The objective of this study was to examine concurrent relationships among alpha-inhibin (as measured using RIA), alphabetaA-inhibin (as measured using IRMA), and other hormones (testosterone, estradiol, LH, FSH) in mares with GCT. Hormone concentrations were measured in single serum or plasma samples obtained from 22 mares with GCT and from 31 normal cycling mares. One GCT mare had blood samples collected at 12-h intervals for 21 days, and at 15-min intervals for two 6-h periods during that time. Results showed that in GCT mares alpha-inhibin was increased to a greater extent, was more uniformly elevated, and had a less variable secretory pattern than did alphabetaA-inhibin. Concentrations of alpha-inhibin and tumor mass were positively correlated (P < 0.01). Concentrations of LH were higher (P < 0.02) in GCT mares than control mares and were positively associated with testosterone concentrations (P = 0.05). Concentrations of FSH tended to be lower in GCT than control mares and were inversely related with alphabetaA-inhibin in GCT mares. Testosterone and estradiol concentrations were variable. It was concluded that immunoreactive alpha-inhibin reflected detection of both alphabetaA-inhibin and free a-subunit. Free alpha-subunit was evidently secreted at a relatively steady rate dependent upon mass of the GCT, whereas secretion of alphabetaA-inhibin was more responsive to FSH regulation. Determination of alpha-inhibin using RIA appeared to be a more reliable indicator of the presence of a GCT than specific measurement of alphabetaA-inhibin using IRMA.
Publication Date: 2002-06-04 PubMed ID: 12041692DOI: 10.1016/s0093-691x(02)00658-1Google Scholar: Lookup
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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The study examined the relationship between inhibin, a hormone, and granulosa cell tumors in mares. It discovered that the measurement of inhibin levels might be useful in diagnosing this type of tumor.
Research Objectives
- The principal objective of the study was to investigate the links among alpha-inhibin and alphabetaA-inhibin, two forms of inhibin, along with other hormones such as testosterone, estradiol, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) in mares with granulosa cell tumors (GCT).
- These hormones were measured in serum or plasma samples collected from 22 mares with GCT and from 31 healthy mares.
Research Methodology
- The concentrations of inhibin were determined using Radioimmunoassay (RIA), which recognizes both dimeric alphabetaA-inhibin and the free inhibin alpha-subunit, and a two-site immunoradiometric assay (IRMA) specific for alphabetaA-inhibin.
- In addition, one mare with a GCT had her blood collected at regular intervals for 21 days and at 15-minute intervals for two periods of 6 hours during that time.
Major Findings
- The results of the study showed an increase in alpha-inhibin in mares with GCT. It was observed to be more uniformly elevated, and with a less variable secretory pattern than alphabetaA-inhibin.
- There was a positive correlation between alpha-inhibin concentrations and tumor mass.
- LH concentrations were higher in mares with GCT compared to healthy mares and were positively associated with testosterone levels.
- FSH levels were generally lower in mares with GCT than healthy ones, and they were inversely related to alphabetaA-inhibin in mares with GCT.
- The concentrations of testosterone and estradiol were variable among the samples.
Conclusion
- It was concluded that alpha-inhibin, both in its form of alphabetaA-inhibin and free alpha-subunit, could be used as an indicator of GCT.
- The free alpha-subunit seemed to be secreted at a relatively steady rate dependent on the mass of the GCT, whereas the secretion of alphabetaA-inhibin reacted more to FSH regulation.
- The determination of alpha-inhibin using RIA appeared to be a more reliable indicator of the presence of a GCT than the specific measurement of alphabetaA-inhibin by IRMA.
Cite This Article
APA
Bailey MT, Troedsson MH, Wheato JE.
(2002).
Inhibin concentrations in mares with granulosa cell tumors.
Theriogenology, 57(7), 1885-1895.
https://doi.org/10.1016/s0093-691x(02)00658-1 Publication
Researcher Affiliations
- Department of Bioengineering, Clemson University, SC 29634, USA.
MeSH Terms
- Animals
- Dimerization
- Estradiol / blood
- Female
- Follicle Stimulating Hormone / blood
- Granulosa Cell Tumor / blood
- Granulosa Cell Tumor / veterinary
- Horse Diseases / blood
- Horses
- Immunoradiometric Assay
- Inhibins / blood
- Luteinizing Hormone / blood
- Ovarian Neoplasms / blood
- Ovarian Neoplasms / veterinary
- Radioimmunoassay
- Sensitivity and Specificity
- Testosterone / blood
Citations
This article has been cited 3 times.- Heaps LA, Scudder CJ, Lipscomb VJ, Steinbach SM, Priestnall SL, Martineau H, Szladovits B, Fowkes RC, Garden OA. Serum anti-Müllerian hormone concentrations before and after treatment of an ovarian granulosa cell tumour in a cat.. JFMS Open Rep 2017 Jul-Dec;3(2):2055116917722701.
- Frederico LM, Gerard MP, Pinto CR, Gradil CM. Bilateral occurrence of granulosa-theca cell tumors in an Arabian mare.. Can Vet J 2007 May;48(5):502-5.
- Lefebvre R, Theoret C, Doré M, Girard C, Laverty S, Vaillancourt D. Ovarian teratoma and endometritis in a mare.. Can Vet J 2005 Nov;46(11):1029-33.
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