Is Corticosterone Involved in the Reproductive Processes of the Male Lizard, Podarcis sicula sicula?

Manzo, Ciro; Zerani, Massimo; Gobbetti, Anna; Fiore, Maria Maddalena Di; Angelini, F.

doi:10.1006/hbeh.1994.1009

Cited by 83 publications

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“…These authors concluded that garter snakes are less susceptible to the stresses of capture and captivity than are other vertebrates. By contrast, our finding that capture stress causes a marked increase in corticosterone secretion in the brown treesnake is consistent with those for most squamates (Manzo et al, 1994;Dunlap and Wingfield, 1995;Moore et al, 1991; but see Girling and Cree, 1995), rhynchocephalians (Tyrrell andCree, 1998), chelonians (Aguirre et al, 1995;Gregory et al, 1996), and crocodilians (Guillette et al, 1997).…”

Section: Discussionsupporting

confidence: 88%

Effects of Trapping and Subsequent Short-Term Confinement Stress on Plasma Corticosterone in the Brown Treesnake (Boiga irregularis) on Guam

Mathies

Felix

Lance

2001

General and Comparative Endocrinology

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The effects of capture in a live trap and subsequent handling stress on plasma concentrations of corticosterone and other sex steroids were examined in wild male and female brown treesnakes (Boiga irregularis), an introduced species on Guam that has been implicated in the extirpation or decline of many of that island's vertebrate species. Males and females that spent 1 night in a trap had plasma levels of corticosterone about four and two times higher, respectively, than those of the respective free-ranging controls. Mean plasma levels of corticosterone of snakes that had spent 3 nights in a trap were intermediate between, but not significantly different from, those of snakes that had spent 1 night in a trap and free-ranging snakes, suggesting that some acclimation to capture occurred during this period. Snakes that were taken from traps and held in collecting bags for 10 min and 2 h prior to blood sampling had levels of corticosterone about two and three times higher, respectively, than those of control snakes that were taken from traps and bled immediately. Concentrations of plasma corticosterone in free-ranging females were about two times higher than those of males but were well within the range of basal levels observed in other reptiles. Few snakes of potential reproductive size were reproductive (males: 1 of 35; females: 2 of 33), and plasma concentrations of testosterone and progesterone in nonreproductive males and females, respectively, were accordingly low. The possible relationship between corticosterone and these sex steroids, therefore, could not be adequately assessed, although there was a positive relationship between plasma progesterone and corticosterone in the nonreproductive females. Nonetheless, as a prerequisite for studies on the seasonal hormonal cycles of this species on Guam, our observations raise the possibility that the stress caused by trapping could affect the levels of other sex steroids and that, therefore, such studies should use free-ranging individuals.Author Keywords: invasive species; reproduction; reptile; snake; stress response The effects of capture in a live trap and subsequent handling stress on plasma concentrations of corticosterone and other sex steroids were examined in wild male and female brown treesnakes (Boiga irregularis), an introduced species on Guam that has been implicated in the extirpation or decline of many of that island's vertebrate species. Males and females that spent 1 night in a trap had plasma levels of corticosterone about four and two times higher, respectively, than those of the respective free-ranging controls. Mean plasma levels of corticosterone of snakes that had spent 3 nights in a trap were intermediate between, but not significantly different from, those of snakes that had spent 1 night in a trap and free-ranging snakes, suggesting that some acclimation to capture occurred during this period. Snakes that were taken from traps and held in collecting bags for 10 min and 2 h prior to blood sampling had levels of corticosterone about ...

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Section: Discussionsupporting

confidence: 88%

Effects of Trapping and Subsequent Short-Term Confinement Stress on Plasma Corticosterone in the Brown Treesnake (Boiga irregularis) on Guam

Mathies

Felix

Lance

2001

General and Comparative Endocrinology

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“…The animals were collected in the same year (2013); they were maintained in a soil-filled terrarium and fed ad libitum with Tenebrio molitor larvae, for approximately 15 days, the time required to ameliorate the capture stress (Manzo et al, 1994). The experiments were approved by institutional committees (Ministry of Health of the Italian Government) and organized to minimize the number of used animals.…”

Section: Materials and Methods Animalsmentioning

confidence: 99%

P450 aromatase: a key enzyme in the spermatogenesis of the Italian wall lizard, Podarcis sicula

Rosati

Agnese

Fiore

et al. 2016

Journal of Experimental Biology

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P450 aromatase is a key enzyme in steroidogenesis involved in the conversion of testosterone into 17β-estradiol. We investigated the localization and the expression of P450 aromatase in Podarcis sicula testes during the different phases of the reproductive cycle: summer stasis (July-August), early autumnal resumption (September), middle autumnal resumption (October-November), winter stasis (December-February), spring resumption (March-April) and the reproductive period (May-June). Using immunohistochemistry, we demonstrated that the P450 aromatase is always present in somatic and germ cells of P. sicula testis, particularly in spermatids and spermatozoa, except in early autumnal resumption, when P450 aromatase is evident only within Leydig cells. Using real-time PCR and semi-quantitative blot investigations, we also demonstrated that both mRNA and protein were expressed in all phases, with two peaks of expression occurring in summer and in winter stasis. These highest levels of P450 aromatase are in line with the increase of 17β-estradiol, responsible for the spermatogenesis block typical of this species. Differently, in autumnal resumption, the level of P450 aromatase dramatically decreased, along with 17β-estradiol levels, and testosterone titres increased, responsible for the subsequent renewal of spermatogenesis not followed by spermiation. In spring resumption and in the reproductive period we found intermediate P450 aromatase amounts, low levels of 17β-estradiol and the highest testosterone levels determining the resumption of spermatogenesis needed for reproduction. Our results, the first collected in a nonmammalian vertebrate, indicate a role of P450 aromatase in the control of steroidogenesis and spermatogenesis, particularly in spermiogenesis.

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“…Rates of alarm calling and retreat into nest boxes in response to humans decline quickly during the first 10 d, and the behaviors of animals do not change significantly after this time (J. M. Mateo and S. A. Cavigelli, personal observation). Furthermore, in other species, glucocorticoid concentrations increase after animals are placed in captive housing or transferred to a different housing environment, but the levels return to baseline within 10 d (Hansen and Damgaard 1993;Manzo et al 1994;Hennessy et al 1997). Based on these observations we expected that the stress induced by captivity would be attenuated before the study started, with little change thereafter.…”

Section: Study 2: Relationship Between Basal Concentrations Of Serum mentioning

confidence: 99%

A Validation of Extraction Methods for Noninvasive Sampling of Glucocorticoids in Free‐Living Ground Squirrels

Mateo

Cavigelli

2005

Physiological and Biochemical Zoology

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Fecal hormone assays provide a powerful tool for noninvasive monitoring of endocrine status in wild animals. In this study we validated a protocol for extracting and measuring glucocorticoids in freeliving and captive Belding's ground squirrels (Spermophilus beldingi). We first compared two commonly used extraction protocols to determine which performed better with commercially available antibodies. We next verified the preferred extraction method by correlating circulating and fecal glucocorticoid measures from a group of individuals over time. For this comparison, we used both a cortisol and a corticosterone antibody to determine which had greater affinity to the fecal metabolites. Cortisol was the primary circulating glucocorticoid, but both hormones were present in well above detectable concentrations in the blood, which does not occur in other sciurids. In addition, the cortisol antibody showed greater binding with the fecal extracts than did the corticosterone antibody. Finally, we used adrenocorticotropic hormone and dexamethasone challenges to demonstrate that changes in adrenal functioning are reflected in changing fecal corticoid levels. These results suggest that our extraction protocol provides a fast, reliable assay of stress hormones in freeliving ground squirrels without the confounding influence of short-term rises in glucocorticoid concentrations caused by handling and restraint stress and that it can facilitate ecological and evolutionary studies of stress in wild species.

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Is Corticosterone Involved in the Reproductive Processes of the Male Lizard, Podarcis sicula sicula?

Cited by 83 publications

References 0 publications

Effects of Trapping and Subsequent Short-Term Confinement Stress on Plasma Corticosterone in the Brown Treesnake (Boiga irregularis) on Guam

Effects of Trapping and Subsequent Short-Term Confinement Stress on Plasma Corticosterone in the Brown Treesnake (Boiga irregularis) on Guam

P450 aromatase: a key enzyme in the spermatogenesis of the Italian wall lizard, Podarcis sicula

A Validation of Extraction Methods for Noninvasive Sampling of Glucocorticoids in Free‐Living Ground Squirrels

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