Rapid suppression of testosterone secretion after capture in male American alligators (Alligator mississippiensis)

Lance, Valentine A.; Elsey, Ruth M.; Butterstein, George M.; Trosclair, Phillip L.

doi:10.1016/j.ygcen.2003.09.013

Cited by 37 publications

(23 citation statements)

References 35 publications

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“…From the onset of capture, blood samples were typically collected in under 5 min, but, due to logistic diYculties, three subjects were held individually in large plastic buckets for 3-7 min before blood was collected. Based on previous work on snakes and other reptiles (e.g., Moore et al, 2000a,b;Lance et al, 2003), blood collected from all of our subjects was done in an acceptable timecourse for obtaining levels of plasma sex steroids (T, DHT, and E2) that would not be adversely aVected (e.g., suppression) by handling stress.…”

Section: Subject Capture and Processingmentioning

confidence: 99%

Winter profile of plasma sex steroid levels in free-living male western diamond-backed rattlesnakes, Crotalus atrox (Serpentes: Viperidae)

Schuett

Repp

Taylor

et al. 2006

General and Comparative Endocrinology

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Recent Weld studies on the reproductive ecology of western diamond-backed rattlesnakes (Crotalus atrox) from populations in southern Ari typically inaccessible, but in southern Arizona, where environmental conditions are typically mild during winter, adult males frequently bask at or near the entrances of communal dens. Basking activity, therefore, oVers a unique logistical opportunity to assess the complete annual proWle of plasma sex steroid levels in males of a temperate reptile in nature. From November to February, we measured levels of plasma T, DHT, and E2 in adult male C. atrox that were located basking at communal dens. Additionally, cloacal, core body, and ambient air temperatures were obtained to investigate potential relationships between body temperatures and levels of sex steroids. Mean levels of T, DHT, and E2 were rela tively high, and the concentration hierarchy was T > DHT > E2. Mean levels of T, DHT, and E2 showed no signiWcant variation across the four months of sampling; however, E2 levels decreased progressively. In the annul cycle, sex steroid levels during winter were not basal when com pared to values obtained during the active season. Mean cloacal temperatures of basking males were signiWcantly higher than core body tem peratures of non-basking males (inside dens) from November-December, and in February, which suggests that one function of winter basking is to elevate body temperatures. Steroid levels, nonetheless, were not signiWcantly correlated with cloacal temperatures. We suggest that future Weld studies of male C. atrox should: (a) investigate sex steroid levels in non-basking individuals and (b) test whether elevated levels of sex ste roids during winter facilitate the large increases that occur in early spring, which are coincident with the second mating season. Our Wndings on the reproductive biology of C. atrox and other viperids are discussed in the context of the associated-dissociated model of reproduction.

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Section: Subject Capture and Processingmentioning

confidence: 99%

Winter profile of plasma sex steroid levels in free-living male western diamond-backed rattlesnakes, Crotalus atrox (Serpentes: Viperidae)

Schuett

Repp

Taylor

et al. 2006

General and Comparative Endocrinology

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“…Endocrine and physiological responses such as the induction of altered plasma glucocorticoid and glucose concentrations have been investigated in crocodilians following exposure to a stressor (Franklin et al, ; Gunderson, Kools, Milnes, & Guillette Jr, ; Jessop, Tucker, Limpus, & Whittier, ; Lance & Elsey, ; Lance, Elsey, Butterstein, & Trosclair 3rd, ). However, most of these studies have examined a change in plasma concentrations of corticosterone or glucose but did not investigate beyond it.…”

Section: Introductionmentioning

confidence: 99%

Stress responses in the chemistry and mRNA abundance of the peripheral blood in the American alligator

2019

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To monitor physiological and toxicological conditions in an endangered species, noninvasive to minimally invasive sampling methods are needed. We analyzed peripheral blood cells to determine if we could monitor some physiological responses of the American alligator following capture stress. Juvenile American alligators were restrained for 16 h to examine the stress response in plasma and blood cells. Plasma corticosterone concentrations were increased by restraint as were plasma concentrations of aspartate aminotransferase (AST), creatine kinase (CK), uric acid, and glucose; a sexually dimorphic response was seen in AST and CK concentrations. The lapse time of restraint was associated with altered messenger RNA (mRNA) levels of the glucocorticoid receptor (GCR) in red blood cells and JUN proto‐oncogene in both white and red blood cells. A two‐way cluster analysis revealed that two major clusters of factors were associated with the responses seen: (a) mRNA levels of GCR and heat‐shock proteins in both blood cells were associated with plasma corticosterone concentration, whereas (b) androgen receptors and JUN mRNA levels in both blood cells were associated with cloacal temperature and body composition. Blood cells appear to be an excellent source to examine the cellular stress response to steroid hormone signals in mRNA levels. We propose that this approach, using blood cells, could provide essential insights into the molecular responses associated with stress in reptiles as well as many other nontraditional model species, including endangered species.

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“…In male reptiles, an increase in plasma CORT above baseline levels is usually followed by a decrease in baseline T levels (e.g., Lance, Elsey, Butterstein, & Trosclair, 2004). This stressor-induced increase in CORT is often associated with changes in the circulating levels of gonadal steroids.…”

Section: Discussionmentioning

confidence: 99%

“…T levels in sub-adult and adult males decreased from initial values by 2 hours post capture Lance et al (2004) Tuatara (Sphenodon punctatus)…”

Section: Reproductive Hormonesmentioning

confidence: 98%

See 1 more Smart Citation

Stress and Reproduction in Reptiles

Tokarz

Summers

2011

Hormones and Reproduction of Vertebrates

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Rapid suppression of testosterone secretion after capture in male American alligators (Alligator mississippiensis)

Cited by 37 publications

References 35 publications

Winter profile of plasma sex steroid levels in free-living male western diamond-backed rattlesnakes, Crotalus atrox (Serpentes: Viperidae)

Winter profile of plasma sex steroid levels in free-living male western diamond-backed rattlesnakes, Crotalus atrox (Serpentes: Viperidae)

Stress responses in the chemistry and mRNA abundance of the peripheral blood in the American alligator

Stress and Reproduction in Reptiles

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