Endocrine Systems

Atkinson, Shannon; Aubin, David St.; Ortiz, Rudy M.

doi:10.1016/b978-0-12-373553-9.00090-0

Cited by 5 publications

(2 citation statements)

References 54 publications

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“…Endocrine systems regulate body processes via negative feedback loops involving steroid hormones, which ultimately control reproductive processes such as maturation, oestrous and ovulation, pregnancy and seasonal mating behaviour [ 12 ]. For example, the female steroid hormone progesterone is produced at high concentrations during pregnancy and is a known proxy for gestation [ 13 , 14 ]. Glucocorticoids (GCs), such as cortisol and corticosterone, are biochemical markers of the vertebrate stress response, indicating activation of the hypothalamic-pituitary-adrenal axis in response to internal or external stressors [ 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Prolonged baleen hormone cycles suggest atypical reproductive endocrinology of female bowhead whales

et al. 2023

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Serial measurements of hormone concentrations along baleen plates allow for reconstructions of mysticete whale reproductive histories. We assessed gestation and calving interval in bowhead whales ( Balaena mysticetus ) by measuring progesterone, oestradiol, corticosterone and nitrogen stable isotope ratios (δ 15 N) along baleen of 10 females from the eastern Canada-west Greenland population. Three immature females (body size < 14.32 m) had uniformly low progesterone concentrations across their baleen, while seven mature females (body size ≥ 14.35 m) had repeated, sustained elevations of progesterone indicative of pregnancies. The mean duration of progesterone elevations (23.6 ± 1.50 months) was considerably longer than the approximately 14 month gestation previously estimated for this species. We consider several possible explanations for this observation, including delayed implantation or sequential ovulations prior to gestation, strategies that would allow females to maximize their fitness in variable Arctic conditions, as well as suggest modified criteria defining gestation as a shorter component of the entire progesterone peak. Calving intervals varied within and among individuals (mean = 3.7 years; range = range 2.8–5.7 years), providing population-specific reproductive estimates for growth models used in bowhead whale management and conservation.

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Section: Introductionmentioning

confidence: 99%

Prolonged baleen hormone cycles suggest atypical reproductive endocrinology of female bowhead whales

et al. 2023

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“…, Atkinson et al . , Myers et al . ), and (2) evaluating behaviors such as vocalization and activity levels, also used to evaluate the stress response in animals (Lay et al .…”

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confidence: 99%

Maternal buffering of stress response in free‐ranging Pacific harbor seal pups in Alaska

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Atkinson

Hoover-Miller

et al. 2015

Marine Mammal Science

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We examined the effects of maternal buffering in free-ranging Pacific harbor seal pups during capture and handling research procedures. We predicted that pups held with their mother would benefit from social buffering and exhibit lower cortisol concentrations resulting from capture and handling than dependent pups caught without their mothers and weaned pups. We expected that pups captured with their mother that experienced a short separation would exhibit increased stress-induced vocal behavior and activity level compared to dependent weaned pups caught alone. The results showed that the presence of the mother significantly buffered the stress response, as measured by reduced serum cortisol concentrations, in pups captured with their mothers as compared to dependent pups captured alone. Cortisol concentrations of mothers with pups initially were higher than nonlactating females, then diminished. Pups showed a significantly higher rate of vocalization soon after maternal separation compared to single pups separated for a longer period of time. Newly separated pups, especially males, showed a high level of activity compared to the other pups. The results provide unique quantitative evidence of the physiology underlying the maternal-pup bond in a marine mammal, and the role that maternal buffering may play on the stress response of the offspring.

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Stress physiology in marine mammals: how well do they fit the terrestrial model?

et al. 2015

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Stressors are commonly accepted as the causal factors, either internal or external, that evoke physiological responses to mediate the impact of the stressor. The majority of research on the physiological stress response, and costs incurred to an animal, has focused on terrestrial species. This review presents current knowledge on the physiology of the stress response in a lesser studied group of mammals, the marine mammals. Marine mammals are an artificial or pseudo grouping from a taxonomical perspective, as this group represents several distinct and diverse orders of mammals. However, they all are fully or semi-aquatic animals and have experienced selective pressures that have shaped their physiology in a manner that differs from terrestrial relatives. What these differences are and how they relate to the stress response is an efflorescent topic of study. The identification of the many facets of the stress response is critical to marine mammal management and conservation efforts. Anthropogenic stressors in marine ecosystems, including ocean noise, pollution, and fisheries interactions, are increasing and the dramatic responses of some marine mammals to these stressors have elevated concerns over the impact of human-related activities on a diverse group of animals that are difficult to monitor. This review covers the physiology of the stress response in marine mammals and places it in context of what is known from research on terrestrial mammals, particularly with respect to mediator activity that diverges from generalized terrestrial models. Challenges in conducting research on stress physiology in marine mammals are discussed and ways to overcome these challenges in the future are suggested.

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Endocrine Systems

Cited by 5 publications

References 54 publications

Prolonged baleen hormone cycles suggest atypical reproductive endocrinology of female bowhead whales

Prolonged baleen hormone cycles suggest atypical reproductive endocrinology of female bowhead whales

Maternal buffering of stress response in free‐ranging Pacific harbor seal pups in Alaska

Stress physiology in marine mammals: how well do they fit the terrestrial model?

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