Serum testosterone, progesterone, and estradiol concentrations and sexual maturation in spotted seals (Phoca largha)

Zhang, Peijun; Yang, Yong; Han, Jingfeng; Lu, Zengkui; Wang, Limei; Tian, Jing; Wang, Qinguo

doi:10.1016/j.theriogenology.2014.05.013

Cited by 14 publications

(13 citation statements)

References 28 publications

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“…More specifically, in vitro studies with grey seals liver microsomes showed that 2β (CYP3A), 6β (CYP3A, CYP1A), and 16β (CYP2B) hydroxylation of T4 in this species (Li et al 2003). P4 and E2 levels in female ringed and grey seals were in the same range as those reported for harbour, grey seals, and spotted seals at the same reproductive stage (Boyd 1983;Reijnders 1990;Gardiner et al 1996;Mellish and Iverson 2005;Lydersen and Kovacs 2004;Zhang et al 2014). For both species studied, T4 concentrations were higher than those reported in the only other report of T4 in female pinnipeds in otariid seals (Browne et al 2006).…”

Section: Hormone Concentrationssupporting

confidence: 67%

Polychlorinated Biphenyls (PCBs) and Sex Hormone Concentrations in Ringed and Grey Seals: A Possible Link to Endocrine Disruption?

Troisi

Barton

Liori

et al. 2020

Arch Environ Contam Toxicol

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Polychlorinated biphenyls (PCBs) are recognised reproductive and immune system toxicants in marine mammals mediated by endocrine-disrupting mechanisms. As with other predators, seals are exposed to elevated bioaccumulated concentrations of PCBs and other persistent organic pollutants (POPs). Cryopreserved plasma samples from adult ringed (Phoca hispida; n = 39) and grey (Halichoerus grypus; n = 38) seals, sampled between 1998 and 2002 from Baltic Sea, Svalbard, and Sable Island (Canada) were used to investigate relationships between PCB exposure and sex hormone concentrations (progesterone; P4, 17α-hydroxy progesterone; 17α-OH-P4, testosterone; T4, 17β-estradiol; E2, estrone; E3). Immunoassay methods were used for quantification of analytes due to the limited sample volumes available. PCB concentrations were found to be significantly higher in Baltic seals than other sampling locations and were classed as "Exposed" seals while Svalbard and Sable Is seal were classed "Reference" seals (sexes and species separate). Mean hormone concentrations in Exposed seal were lower than Reference seals, and this was statistically significantly for 17α-OH-P4 (both sexes and both species), E2 (ringed and grey seal females), and E3 (grey seal females). Regression analyses (PCB v hormone concentrations) for each sex and species revealed significant correlations for P4 (Sable Is. female grey seals and female ringed seals), 17α-OH-P4 (Sable Is. male grey seals and Svalbard male ringed seals), T4 (Svalbard male ringed seals), E2 (female ringed seals), and E3 (female ringed seals and Baltic female grey seals). Although significant correlations are not evidence of cause and effect, the potential impact of hormone changes on endocrine homeostasis and reproductive health for seal populations warrants further investigation given that PCB concentrations found here are in the same range as those currently reported in seals from these populations.

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Section: Hormone Concentrationssupporting

confidence: 67%

Polychlorinated Biphenyls (PCBs) and Sex Hormone Concentrations in Ringed and Grey Seals: A Possible Link to Endocrine Disruption?

Troisi

Barton

Liori

et al. 2020

Arch Environ Contam Toxicol

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“…Estradiol in blubber from 2015 was below detectable limits in 20 of 22 samples (including duplicates from one 2015 female). From our results, estradiol is most likely not deposited in the blubber layer in high concentrations, possibly due to having relatively low circulating concentrations to begin with in male and female pinnipeds . Female walruses usually enter estrus twice in the year, around January and late August .…”

Section: Resultsmentioning

confidence: 79%

“…Subadult males (3–14 years) did not have significantly different testosterone concentrations compared with adult males (15–28 years old, P = 0.34, Table A). In previous studies of male spotted seals ( Phoca largha ) and a male walrus, testosterone concentrations were higher in mature males . If bone testosterone was higher in adults compared with subadults, this would be an indication of a short‐term reservoir time of testosterone in cortical bone .…”

Section: Resultsmentioning

confidence: 92%

“…In previous studies of male spotted seals ( Phoca largha ) and a male walrus, testosterone concentrations were higher in mature males . If bone testosterone was higher in adults compared with subadults, this would be an indication of a short‐term reservoir time of testosterone in cortical bone . Additionally, the similarity of subadults and adults could be an indication of harem‐style breeding typical for walruses, with few dominant reproductive males, who would have higher testosterone concentrations, and a majority of subordinate males with lower testosterone levels similar to subadult males .…”

Section: Resultsmentioning

confidence: 95%

“…Of the modern ND samples (total n = 19), males had ND concentrations of progesterone ( n = 6 of 10) and estradiol (n = 1 of 9). Progesterone and estradiol would be expected to be low in male walruses, because progesterone and estradiol are female reproductive hormones and only play a minor role in male reproduction . In females, estradiol does not remain elevated for extended periods of time in pregnant walruses compared with progesterone, which may stay elevated for up to 9 months throughout a pregnancy .…”

Section: Resultsmentioning

confidence: 99%

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A novel method to measure steroid hormone concentrations in walrus bone from archaeological, historical, and modern time periods using liquid chromatography/tandem mass spectrometry

Charapata

Horstmann

Jannasch

et al. 2018

Rapid Comm Mass Spectrometry

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RationaleA liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was validated and utilized to measure and analyze four steroid hormones related to stress and reproduction in individual samples from a novel tissue, Pacific walrus (Odobenus rosmarus divergens, herein walrus) bone. This method determines steroid hormone concentrations in the remote walrus population over millennia from archaeological (>200 bp), historical (200–20 bp), and modern (2014–2016) time periods.MethodsLipids were extracted from walrus bone collected from these periods using methanol before LC/MS/MS analysis. Isotopically labeled internal standards for each target hormone were added to every sample. Analytical and physiological validations were performed. Additionally, a tissue comparison was done among paired walrus bone, serum, and blubber samples. A rapid resolution liquid chromatography system coupled to a QqQ mass spectrometer was used to analyze all samples after derivatization for progesterone, testosterone, cortisol, and estradiol concentrations. Multiple reaction monitoring was used for MS analysis and data were acquired in positive electrospray ionization mode.ResultsProgesterone, testosterone, cortisol, and estradiol were linear along their respective standard calibration curves based on their R2 values (all > 0.99). Accuracy ranged from 93–111% for all hormones. The recovery of extraction, recovery of hormones without matrix effect, was 92–101%. The overall process efficiency of our method for measuring hormones in walrus bone was 93–112%. Progesterone and testosterone concentrations were not affected by reproductive status among adult females and males, respectively. However, estradiol was different among pregnant and non‐pregnant adult females. Overall, steroid hormones reflect a long‐term reservoir in cortical bone. This method was also successfully applied to walrus bone as old as 3585 bp.ConclusionsLC/MS/MS analysis of bone tissue (0.2–0.3 g) provides stress and reproductive data from elusive walruses that were alive thousands of years ago. Based on physiological validations, tissue comparison, and published literature, steroid hormone concentrations measured in walrus cortical bone could represent an accumulated average around a 10–20‐year time span. By investigating how stress and reproductive physiology may have changed over the past ~3000 years based on bone steroid hormone concentrations, this method will help answer how physiologically resilient walruses are to climate change in the Arctic.

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Endocrine assessment of ovarian cycle activity in wild female mountain gorillas (Gorilla beringei beringei)

Habumuremyi

Stephens

Fawcett

et al. 2016

Physiology & Behavior

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Serum testosterone, progesterone, and estradiol concentrations and sexual maturation in spotted seals (Phoca largha)

Cited by 14 publications

References 28 publications

Polychlorinated Biphenyls (PCBs) and Sex Hormone Concentrations in Ringed and Grey Seals: A Possible Link to Endocrine Disruption?

Polychlorinated Biphenyls (PCBs) and Sex Hormone Concentrations in Ringed and Grey Seals: A Possible Link to Endocrine Disruption?

A novel method to measure steroid hormone concentrations in walrus bone from archaeological, historical, and modern time periods using liquid chromatography/tandem mass spectrometry

Endocrine assessment of ovarian cycle activity in wild female mountain gorillas (Gorilla beringei beringei)

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