Measuring the Effects of a Single Dose of Human Chorionic Gonadotropin (hCG) on Plasma Testosterone Concentrations in Leopard Geckos (Eublepharis macularius)

Mason, Alexandra K.; Perry, Sean M.; Boykin, Kimberly; Mitchell, Mark A.

doi:10.5818/jhms-d-21-00013

Cited by 4 publications

(5 citation statements)

References 29 publications

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“…Although species differences or seasonality may impact the response to hCG, leopard geckos showed no elevation in testosterone concentrations with administration of hCG at two doses (Mason et al ., 2021a). Alternative exogenous hormones, such as LH, LH releasing hormone, or PMSG may also be considered; however, PMSG may provide more utility in reptiles (Mason et al ., 2021b). In mammals, the biological effects and immunological cross-reactivity of hCG and LH have been found to be similar (Bell et al ., 1969); however, in lizards it has been documented that interstitial cells appear to be more sensitive to hCG than LH, with two exceptions (Reddy and Prasad, 1970b; Eyeson, 1971); however, both of these studies used pituitary extracts.…”

Section: Discussionmentioning

confidence: 99%

“…We elected to use ultrasound for measuring testicle size because it is a noninvasive method. This technique was selected because our ultimate goal is to develop clinical, antemortem methods that can be used to assess the reproductive cycle of male reptiles (Mason et al, 2021a(Mason et al, , 2021bPerry et al, , 2023. Based on previous studies, ultrasound is sensitive enough to detect changes in testicular size in reptiles (Mason et al, 2021a;Perry et al, , 2023.…”

Section: Spermatozoa Parameter Amentioning

confidence: 99%

“…Exogenous hormonal stimulation has been evaluated in male lizards from the following species: leopard gecko ( Eublepharis macularis ), little brown skink ( Leiolopisma laterale ), common agama ( Agama agama ), green anole ( Anolis carolinensis ), common wall lizard ( Lacerta muralis ), broadhead skink ( Eumeces laticep ), Indian spiny-tailed lizard ( Uromastix harkwickii ), Indian wall lizard ( Hemidactylus flaviviridis ), and oriental garden lizard ( Calotes versicolor ). The exogenous hormones used in these studies include ovine luteinizing hormone (LH), human chorionic gonadotropin (hCG), follicle stimulating hormone (FSH), ovine FSH (oFSH), porcine FSH, ovine prolactin, equine LH, and pregnant mare serum gonadotropin (PMSG; Licht and Pearson 1969; Prasad and Sanyakl, 1969; Reddy and Prasad, 1970a, 1970b; Eyeson, 1971; Licht and Papkoff, 1971; Jones, 1973; Jalali et al ., 1976; Arslan et al ., 1977; Licht, 1979; Lance et al ., 1985; Haider and Rai, 1987; Lance and Vilet, 1987; Sonar and Patil, 1994; Vijaykumar et al ., 2002; Edwards et al ., 2004; Jadhav and Padgaonkar, 2010; Mason et al ., 2021a, 2021b). In squamates, a one gonadotroph two cell theory is accepted, with the primary gonadotroph being FSH-like (Tsui and Licht, 1977; Licht, 1979).…”

Section: Introductionmentioning

confidence: 99%

“…Although these studies suggest gonadal histological changes with hCG administration, in the common agama, hCG (100 IU/animal) did not lead to an increase in testicular size, whereas an increase in testicular size was observed with PMSG, but no endogenous hormones were evaluated in that study (Eyeson, 1971). In one of the few studies with hormone analysis reported in reptiles, hCG at a dose of 50 or 100 IU did not increase plasma testosterone concentrations in leopard geckos within 24 h of administration (Mason et al ., 2021b). Most studies have observed gonadal changes with hCG administration, but few evaluated hormonal changes in response to hCG administration.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Exogenous Human Chorionic Gonadotropin Administration on Plasma Testosterone and Semen Production in the Veiled Chameleon (Chamaeleo calyptratus)

Perry

Camlic²,

Lierz

et al. 2023

Journal of Herpetological Medicine and Surgery

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Gamete collection, gamete preservation, hormone analysis, and artificial insemination have become integral parts of in situ and ex situ conservation programs for threatened and endangered species, and while these methods have been used to assist conservation in many different vertebrate groups, limited work has been done in reptiles. For example, semen collection in lizards has only recently been described and determined to be safe. The purpose of this study was to determine effective doses of human chorionic gonadotropin (hCG) for increasing plasma testosterone concentrations in the veiled chameleon (Chamaeleo calyptratus), as well as to determine whether the rise in testosterone impacts semen collection. A cross-over design was used. Chameleons were given injections of 100 IU, 200 IU, and 300 IU of hCG/animal and serial plasma testosterone measurements were collected over 24 hours. 100 IU/animal was determined to increase plasma testosterone concentrations similar to 200 IU, and 300 IU/animal. Following this, we determined weekly injections of hCG (100 IU/animal) would maintain elevated testosterone concentrations over 30 days. Additionally, we determined that elevated testosterone secondary to repeated injections of hCG decreased testicular size as determined by ultrasound. Repeated hCG injections and long-term elevation of plasma testosterone concentrations did not increase the likelihood to collect a semen sample with electroejaculation or improve ejaculate quality. Further research is needed to exogenously stimulate spermatogenesis and increase ejaculate quality to perform timed semen collections in male reptile species.

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Section: Discussionmentioning

confidence: 99%

Section: Spermatozoa Parameter Amentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of Exogenous Human Chorionic Gonadotropin Administration on Plasma Testosterone and Semen Production in the Veiled Chameleon (Chamaeleo calyptratus)

Perry

Camlic²,

Lierz

et al. 2023

Journal of Herpetological Medicine and Surgery

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“…The results of experiments attempting to influence the hormonal activity of reptile testicles have also been negative (Kirchgessner et al 2009;Mason et al 2021). Further research in this direction is therefore still relevant.…”

Section: Conflict Of Interestmentioning

confidence: 99%

Effect of GnRH agonist (deslorelin) on reproductive activity in captive female veiled chameleons (Chamaeleo calyptratus)

Cermakova,

Knotkova,

Boruvka

et al. 2023

Vet. Med.

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Eighteen 5 months old veiled chameleon females (Chamaeleo calyptratus) were used in the study. Seven females received subcutaneous implants with gonadotropin-releasing hormone agonist (GnRH) deslorelin acetate whereas eleven females were used as control animals without any implants. Females were kept in five terraria, in groups of four females (in 3 terraria) and groups of three females (in 2 terraria), respectively. A minimum of one female with GnRH implants was present in each terrarium. They were kept under standard husbandry conditions. Females of both groups (females with GnRH and controls, respectively) were monitored for three years. No differences between females with GnRH implants and females without GnRH implants were observed with respect to the presence of large ovarian follicles, number of eggs/female, or number of clutches/female. GnRH implants did not prevent spontaneous reproductive activity in any of the 7 females with implants. Ovariectomy was performed in 8 females (4 females with GnRH implants and 4 control females). Ten females (3 females with GnRH implants and 7 control females) had to be euthanised. In 17 of 18 female veiled chameleons of this study histologic examination revealed heterophilic granulomatous oophoritis. The use of GnRH agonist implants did not prove to be an appropriate method for the control of reproductive function in captive female veiled chameleons.

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Determining the Effects of Serial Injections of Pregnant Mare Serum Gonadotropin on Plasma Testosterone Concentrations, Testicular Dynamics, and Semen Production in Leopard Geckos (Eublepharis macularius)

Mason

Lee

Perry³

et al. 2021

Animals

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Reptiles are highly susceptible to anthropogenic activities as a result of their narrow geographical ranges and habitat specialization, making them a conservation concern. Geckos represent one of the mega-diverse reptile lineages under pressure; however, limited assisted reproductive technologies currently exist for these animals. Exogenous pregnant mare serum gonadotropin (PMSG) has been found to exhibit follicle stimulating hormone-like action and has been routinely used to alter reproductive hormones of vertebrates in assisted reproductive protocols. The purpose of this study was to determine the effects of serial injections of 20 IU and 50 IU PMSG on circulating testosterone concentrations, testicular dynamics, and semen production in a model species of gecko. Twenty-four captive-bred, adult, male leopard geckos (Eublepharis macularius) were divided into three treatment groups and administered a once-weekly injection of either PMSG or saline for a total of nine weeks. Ultrasonographic testicular measurements, electrostimulation for semen collection, and venipuncture were performed on days 0, 21, 42, and 63. Right unilateral orchidectomies and epididymectomies were performed in all animals on day 63; tissues were submitted for histopathology. PMSG treated geckos had significantly higher testicular volumes and weights, spermatozoa motility, and spermatozoa concentrations compared with controls. However, there were no significant differences in testosterone concentrations by treatment or time. Under the conditions outlined, PMSG is effective at stimulating spermatogenesis and increasing testicular size, but not effective at increasing testosterone concentrations in the leopard gecko between October–December in the Northern hemisphere.

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Measuring the Effects of a Single Dose of Human Chorionic Gonadotropin (hCG) on Plasma Testosterone Concentrations in Leopard Geckos (Eublepharis macularius)

Cited by 4 publications

References 29 publications

Effects of Exogenous Human Chorionic Gonadotropin Administration on Plasma Testosterone and Semen Production in the Veiled Chameleon (Chamaeleo calyptratus)

Effects of Exogenous Human Chorionic Gonadotropin Administration on Plasma Testosterone and Semen Production in the Veiled Chameleon (Chamaeleo calyptratus)

Effect of GnRH agonist (deslorelin) on reproductive activity in captive female veiled chameleons (Chamaeleo calyptratus)

Determining the Effects of Serial Injections of Pregnant Mare Serum Gonadotropin on Plasma Testosterone Concentrations, Testicular Dynamics, and Semen Production in Leopard Geckos (Eublepharis macularius)

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