Nasal Administration of Gonadotropin Releasing Hormone (Gnrh) Elicits Sperm Production in Fowler’s Toads (Anaxyrus fowleri)

ORCID

CKouba: https://orcid.org/0000-0001-8466-6077

MSU Affiliation

College of Agriculture and Life Sciences; Department of Biochemistry, Molecular Biology, Entomology and Plant Pathology; Department of Animal and Dairy Sciences; College of Forest Resources; Department of Wildlife, Fisheries and Aquaculture

Creation Date

2026-10-30

Abstract

Background: Declining amphibian populations around the world necessitate the establishment of captive assurance colonies as a hedge against extinction. For species that are difficult to breed in captivity, assisted reproductive techniques, such as treatment with exogenous hormones, are necessary for successful reproduction. The purpose of this study was to determine whether intranasal administration of a gonadotropin releasing hormone analog (GnRHa) elicits sperm production in anurans. Methods: Male Anaxyrus fowleri (n = 15/trt) were nasally administered GnRHa (1, 5, 10, and 20 μg) in phosphate buffered saline (PBS) using a pipette. Spermic urine was collected from animals over an 8 h period. Samples were assessed for sperm presence, motility, and concentration. Results: Treatment of male toads with a PBS control and 1 μg of GnRHa did not elicit sperm production. Nasal administration of GnRHa resulted in sperm production from 60, 93, and 80% of males in the 5, 10, and 20 μg treatment groups, respectively. Sperm motilities averaged 70, 63, and 52% within the 5, 10, and 20 μg treatment groups, respectively, with the highest (p < 0.05) sperm motility observed using 5 μg of GnRHa. Significantly higher sperm concentrations were observed in males treated with 10 μg of GnRHa compared with 5 or 20 μg ofGnRHa. Conclusion: Nasal administration of GnRHa was successful in eliciting spermiation from male Anaxyrus fowleri, which typically began less than 3 h after treatment. Nasal administration of GnRHa may provide a novel non-invasive method of hormone delivery for at-risk amphibian species that have low reproductive output.

Keywords

amphibian, captive-breeding, hormones, reproduction, sperm, toad

Publication Date

5-22-2019

Publication Title

BMC Zoology

Publisher

BioMed Central

Last Page

10

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Rights

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

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Digital Object Identifier (DOI)

https://doi.org/10.1186/s40850-019-0040-2