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Legacki E, Sattler R, Conley A. Longitudinal patterns in progesterone metabolites in pregnant and non-pregnant Steller sea lions (Eumetopias jubatus). Gen Comp Endocrinol 2022; 326:114069. [PMID: 35679975 DOI: 10.1016/j.ygcen.2022.114069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 05/17/2022] [Accepted: 06/02/2022] [Indexed: 11/04/2022]
Abstract
Similar to the several pinniped and a few terrestrial carnivore species, the Steller sea lion has a seasonal synchronized mating scheme enabled by a female reproductive cycle that includes embryonic diapause, delayed implantation, and pseudopregnancy (a state in which the corpus luteum produces progesterone for approximately as long as in pregnant females). Due to this, circulating systemic progesterone concentrations cannot be used to differentiate pregnant and nonpregnant females during early gestation. With the use of advanced measurement technologies such as liquid chromatography tandem mass spectrometry (LC-MS/MS) additional steroid hormones are measurable which can provide additional information on the endocrine pathways throughout gestation. Our objectives were to further characterize endocrine patterns in female Steller sea lion pregnancy by 1) quantifying longitudinal profiles of hormone metabolites in pregnant and non-pregnant female sera, and 2) evaluating hormone profiles to identify pregnant animals within the early stage of gestation. Three gestation stages were delineated based on what is believed to be the period of implantation (September-October): EARLY (August- November), MID (December-February), and LATE (March to May). Five steroids, Progesterone (P4), 5α-dihydroprogesterone (DHP), 17αOH-progesterone (17OHP), 20αOH-progesterone (20OHP), and androstenedione (A4), were detected in both pregnant and non-pregnant animals. A significant difference in P4 concentrations was measured between EARLY and MID gestation (p ≤ 0.01) in both pregnant and non-pregnant animals. During MID gestation there was a significant difference (p ≤ 0.05) between pregnant and non-pregnant animals in all pregnanes measured. Significant patterns of correlation between P4 and 17OHP and between P4 and DHP were detected during EARLY and MID gestation in non-pregnant animals. While those significant correlations also exist in EARLY pregnant animals, this pattern was lost by MID gestation. This loss of correlation suggests a potential shift in progesterone metabolism from ovarian to alternative tissue (e.g. fetal gonads or adrenal glands) by MID gestation in Steller sea lions. We were unable to identifying a steroid hormone biomarker capable of differentiating pseudopregnancy from pregnant animals and conclude that such a biomarker likely falls outside of the traditional progesterone metabolic pathway.
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Affiliation(s)
- Erin Legacki
- School of Veterinary Medicine, University of California Davis, Davis, CA 95616, United States; National Cold Water Marine Aquaculture Center, USDA, Franklin, ME 04469, United States.
| | - Renae Sattler
- Alaska Department of Fish and Game, Palmer, AK 99645, United States; Alaska SeaLife Center, 301 Railway Avenue, Seward, AK 99664, United States
| | - Alan Conley
- School of Veterinary Medicine, University of California Davis, Davis, CA 95616, United States
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Kohyama K, Inoshima Y, Kiyota M. Fluctuations in serum steroid hormone concentrations and body mass during growth and sexual maturation in captive northern fur seals (Callorhinus ursinus). J Vet Med Sci 2021; 84:171-180. [PMID: 34866092 PMCID: PMC8810328 DOI: 10.1292/jvms.21-0330] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Northern fur seals (Callorhinus ursinus) have a distinct life history pattern comprising annual terrestrial breeding and oceanic migration, and the physiological changes
associated with these patterns are of particular interest for understanding their environmental adaptations. However, owing to their oceanic distribution, limited information is available on
the reproductive physiology of wild individuals during the immature stage and the winter migration period. This study aimed to determine the relationships among the seasonal hormone
profiles, body growth, age, and pregnancy using monthly serum samples collected over 3–5 years from two male and two female captive individuals during pubescence and sexual maturation. Small
increases in the serum testosterone signaled puberty in males aged 3 and 4 years. Thereafter, males showed considerable increases in testosterone during breeding seasons, indicating sexual
maturity. Immature female serum progesterone was maintained at low levels, but after pubescence, females showed an increase in serum progesterone in August, the month next to the peak of
delivery, followed by a decrease. In non-pregnant females, progesterone did not increase significantly until the next breeding season, but in pregnant females, they increased again from
February to March and then gradually decreased. Immature males increased body mass constantly and reached puberty when their body mass exceeded 20 kg, and they showed seasonal weight
fluctuations after puberty. These results provide fundamental information for determining sexual maturity and pregnancy in this species based on sex steroid hormones and body mass
measurements.
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Affiliation(s)
| | - Yasuo Inoshima
- Cooperative Department of Veterinary Medicine, Gifu University.,The United Graduate School of Veterinary Sciences, Gifu University.,Education and Research Center for Food Animal Health, Gifu University (GeFAH).,Joint Graduate School of Veterinary Sciences, Gifu University
| | - Masashi Kiyota
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University
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Magnus G, Dutton C, Mastromonaco G, Gartley C, MacDonald S, Franke M. Luteal phase length, endometrial edema, and behavior differentiate post-ovulatory events in a giant panda (Ailuropoda melanoleuca). Zoo Biol 2021; 41:130-142. [PMID: 34672395 DOI: 10.1002/zoo.21655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 08/16/2021] [Accepted: 10/01/2021] [Indexed: 11/11/2022]
Abstract
Despite decades of reproductive research on the giant panda (Ailuropoda melanoleuca), the post-ovulatory phase continues to confound zoologists in conservation and breeding centers around the world, often resulting in significant investments of time and resources without reproductive success. The purpose of this project was to document and compare post-ovulatory characteristics during a non-productive and productive breeding in the same individual in consecutive years. A multidisciplinary approach was used to monitor the visiting female giant panda at the Toronto Zoo through the luteal phase of her first two full reproductive cycles in 2014 and 2015. Monitoring occurred via urine-endocrine analysis, weekly ultrasound examinations, and continuous behavioral observations. The 2014 reproductive cycle consisted of a pseudopregnancy, characterized by an extended luteal phase (241 days), the identification of endometrial edema and folding during ultrasound examinations, and a lack of strong association between behavior patterns and urinary progestagen secretion. The 2015 reproductive cycle included increased feeding time through the primary progestagen rise compared to the previous year, followed by simultaneous decrease in appetite and increases in inactivity, resting, sitting upright, and pre-partum-associated behaviors. These changes began 25 days before the birth of twins on Day 153 post-ovulation. Both fetuses were detected via ultrasound 15 days pre-partum. These results suggest that an absence of pre-partum behaviors, ultrasound evidence of endometrial edema without a fetus, and an extended luteal phase may be indicative of pseudopregnancy in giant pandas. Simultaneous monitoring of morphology, behavior, and urinary-endocrine profiles showed clear differences between successful and unsuccessful reproductive years.
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Affiliation(s)
- Gabriel Magnus
- Department of Wildlife and Science, Toronto Zoo, St. Catharines, Ontario, Canada
| | | | | | - Cathy Gartley
- Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada
| | | | - Maria Franke
- Department of Wildlife and Science, Toronto Zoo, St. Catharines, Ontario, Canada
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Keogh MJ, Charapata P, Fadely BS, Zeppelin T, Rea L, Waite JN, Burkanov V, Marshall C, Jones A, Sprowls C, Wooller MJ. Whiskers as a novel tissue for tracking reproductive and stress-related hormones in North Pacific otariid pinnipeds. CONSERVATION PHYSIOLOGY 2021; 9:coaa134. [PMID: 33489238 PMCID: PMC7808128 DOI: 10.1093/conphys/coaa134] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 11/07/2020] [Accepted: 12/15/2020] [Indexed: 05/30/2023]
Abstract
Keratinized tissues, including whiskers, are ideal for acquiring a record of physiological parameters. Most tissues provide a snapshot of physiological status; however, whiskers may support longitudinal sampling for reproductive and stress-related hormones, if hormones are incorporated as whiskers grow and concentrations change with physiological state. Whiskers from female Steller sea lions (Eumetopias jubatus) and northern fur seals (Callorhinus ursinus) were serially sectioned and pulverized and steroid hormones were extracted. Standard methods were used to validate enzyme immunoassay kits for cortisol, progesterone, 17β-estradiol and testosterone. All hormones were measurable in whisker segments from both species with progesterone concentrations showing cyclical patterns, which appear to signify previous pregnancies or luteal phases. Yearly progesterone concentrations were greater in years a pup was produced compared with years when no pup was observed. Free-ranging female Steller sea lions had reproductive rates between 0 and 1.0 (0.53 ± 0.33, n = 12) using a yearly progesterone concentration of 30 pg/mg or greater to classify a reproductive year as producing a pup and below 30 pg/mg as non-reproductive. Cortisol concentrations were greater near the root and rapidly declined, lacking any obvious patterns, throughout the rest of the whisker. Progesterone and testosterone concentrations were able to help determine sex of unknown individuals. Immunohistochemistry revealed that steroid hormones most likely do not leach out of whiskers based on the deposition patterns of progesterone and cortisol being present throughout the whisker length. Overall, measuring steroid hormones in whiskers can reveal individual reproductive histories over multiple years in sea lions and fur seals. Cyclical patterns of δ15N were useful for identifying periods of up to ~10 years of growth within whiskers, and measuring both stable isotopes and hormones may be useful for differentiating periods of active gestation from diapause and potentially track multi-year reproductive histories of female otariids.
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Affiliation(s)
- Mandy J Keogh
- Division of Wildlife Conservation, Alaska Department of Fish and Game, P.O. Box 110024 Douglas, AK 99811-0024, USA
| | - Patrick Charapata
- Division of Wildlife Conservation, Alaska Department of Fish and Game, 1300 College Road, Fairbanks, AK 99701, USA
- Biology Department, Baylor University, One Bear Place #97388, Waco, TX 76798, USA
| | - Brian S Fadely
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - Tonya Zeppelin
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115, USA
| | - Lorrie Rea
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Jason N Waite
- Division of Wildlife Conservation, Alaska Department of Fish and Game, P.O. Box 110024 Douglas, AK 99811-0024, USA
| | - Vladimir Burkanov
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 7600 Sand Point Way NE, Seattle, WA 98115, USA
- Kamchatka Branch of the Pacific Geographical Institute Far East Branch, Russian Academy of Sciences, Petropavlovsk-Kamchatsky 683000, Russia
| | - Chris Marshall
- Department of Marine Biology, Texas A&M University, Galveston Campus, Galveston, TX 77553, USA
- Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, TX 77843, USA
| | - Aubree Jones
- Department of Marine Biology, Texas A&M University, Galveston Campus, Galveston, TX 77553, USA
| | - Caitlin Sprowls
- Department of Marine Biology, Texas A&M University, Galveston Campus, Galveston, TX 77553, USA
| | - Matthew J Wooller
- Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
- Alaska Stable Isotope Facility, Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
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Larsen Tempel JT, Atkinson S. Endocrine profiling of reproductive status and evidence of pseudopregnancy in the Pacific walrus (Odobenus rosmarus divergens). PLoS One 2020; 15:e0239218. [PMID: 32931507 PMCID: PMC7491731 DOI: 10.1371/journal.pone.0239218] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 09/01/2020] [Indexed: 01/05/2023] Open
Abstract
Endocrine profiling is an increasingly utilized tool for detecting pregnancies in wild populations of mammals. Given the difficulty in calculating reproductive rates of Pacific walruses (Odobenus rosmarus divergens) the use of endocrine techniques for determining pregnancy rates could be particularly useful for management of the population. The goals of this study were to 1) determine if progesterone and total estrogen concentrations in ovarian tissues of female walruses could be used to determine reproductive state and 2) determine if walruses undergo a functional postpartum estrus, as is seen in other pinnipeds. Ovaries were collected from female walruses (n = 13) hunted in subsistence hunts by Alaska Native communities. Females were categorized as postpartum, full-term pregnant, pregnant diapause or unbred. Total estrogen concentrations were greatest in unbred (n = 2) and pregnant (n = 2) females. Progesterone concentrations were also nominally larger in unbred (n = 2) than pregnant (n = 2) and postpartum (n = 9) animals. Small samples sizes precluded the use of statistical comparisons among groups. Corpora lutea tissue samples in this study did not reflect the presence of a postpartum estrus in the month of May as postpartum females yielded lower total estrogen concentrations than unbred or pregnant animals. Both unbred animals were in a state of pseudopregnancy, which has not been physiologically described for this species before. The progesterone profiles in late (59 ng/g) and early (140 ng/g) pregnancy were lower than expected and fell within the range of the postpartum females (36-210 ng/g), suggesting low production of the hormone by the corpus luteum during these phases of pregnancy. Profiling reproductive hormones in free-ranging walruses demonstrates that an endocrine approach may be a valuable tool for determining reproductive status of females, however increased sample sizes and time of year must be considered to accurately separate pregnant versus pseudopregnant individuals.
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Affiliation(s)
- Jenell T. Larsen Tempel
- Fisheries Department, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau Campus, Juneau, Alaska, United States of America
| | - Shannon Atkinson
- Fisheries Department, College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau Campus, Juneau, Alaska, United States of America
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