Vitamin A in seals

Rodahl, Kaare; Davies, A. W.

doi:10.1042/bj0450408

Cited by 26 publications

(18 citation statements)

References 2 publications

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“…Blubber is the fattest compartment in marine mammals and it has been proposed that this tissue is an important body depot for retinoids in pinnipeds (Schweigert et al 1987, 2002, Käkelä et al 1997. In cetaceans, information is more limited, but the high blubber retinoid levels found in the present study, and those reported in a similar study on harbour porpoises (Borrell et al 1999), are comparable to those found in grey seals (Schweigert et al 1987, 2002, Schweigert & Buchholz 1995, Nyman et al 2003) and ringed seals (Käkelä et al 1997), but much higher than those reported in harp seals (Rodahl & Davies 1949).…”

Section: Discussionsupporting

confidence: 75%

“…The concentrations found were lower than those found in the liver of other cetacean species, such as blue, fin (Balaenoptera physalus) and sperm whales (SchmidtNielsen et al 1934, Klem 1935, Wagner 1939, Braekkan 1948. In comparison to other marine mammals, our concentrations were higher than those reported for harbour and freshwater ringed seals (Rodahl & Davies 1949, Käkelä et al 1997, Mos & Ross 2002, similar to those in hooded and marine ringed seals and California sea lions Zalophus californianus (Rodahl & Davies 1949, Ball et al 1992, Käkelä et al 1997, and lower than those reported for harp, grey, fur (Arctocephalus pusillus doriferus) and bearded seals Erignathus barbatus and polar bears Ursus maritimus (Rodahl & Moore 1943, Rodahl & Davies 1949, Southcott et al 1974, Ball et al 1986, Schweigert et al 1987, 2002.…”

Section: Discussioncontrasting

confidence: 39%

“…Kidney values for common dolphins were similar to those found in grey seals (Rodahl & Davies 1949, Schweigert et al 2002 and higher than those in harp seals (Rodahl & Davies 1949). Nevertheless, all kidney concentrations were several orders of magnitude lower than those of the liver and, occasionally, almost bordered analytical detection limits.…”

Section: Discussionmentioning

confidence: 55%

“…The body distribution of retinoids is significantly affected by the physicochemical properties of their molecules; thus, not only do retinoids concentrate in lipid-rich tissues, but also their concentration within a given tissue is proportional to the lipid content of this tissue. However, this relationship was not observed by Rodahl & Davies (1949) in hooded seals Cystophora cristata and harp seals, by Borrell et al (1999) in harbour porpoises, or by Mos & Ross (2002) in harbour seal pups. Lactation, migration, disease and other factors cause the mobilization of lipids and, presumably, that of the blubber-associated retinoid reserves.…”

Section: Discussionmentioning

confidence: 83%

“…In grey, ringed, harbour (Phoca vitulina), and harp seals Pagophilus groenlandicus, the liver presented the highest retinoid concentrations, although those of the blubber were also elevated (Rodahl & Davies 1949, Schweigert et al 1987, Schweigert & Buchholz 1995, Käkelä et al 1997, Mos & Ross 2002, Schweigert et al 2002, Nyman et al 2003. Lower concentrations are found in other tissues, such as kidney, lung, retina, pancreas, skin and spleen (Rodahl & Davies 1949, Schweigert & Buchholz 1995, Mos & Ross 2002. In cetaceans, data on retinoid concentrations are available only for some tissues, but results are not comparable between studies because of significant variation at individual, population and species levels.…”

Section: Introductionmentioning

confidence: 99%

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Tissue distribution of retinoids in common dolphins Delphinus delphis

Tornero

Borrell²,

Forcada³

et al. 2004

Mar. Ecol. Prog. Ser.

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Exposure to organochlorines induces retinoid deficiency in mammals; hence, retinoids are potential biomarkers of the impact of these pollutants. Appropriate target tissues to monitor retinoids in cetaceans have not been properly identified because of a lack of information on the contribution of each tissue to total body retinoids. Therefore, we have addressed this issue by studying the contribution of the main body tissues to retinoids in 21 common dolphins obtained from incidental catches and in apparent good health and nutritive condition. Although concentrations in the liver were highest, those in blubber were also high and accounted for 43% of the total retinoid load of the compartments examined. As blubber can be obtained using non-invasive biopsy techniques, this tissue is proposed as a reliable indicator of retinoid status in cetaceans. However, blubber topographical variation in structure and composition requires standardization of sampling sites. Retinoid concentrations did not differ significantly between sexes or with body size for any of the tissues, but the lipid content of blubber strongly influenced these concentrations. Biopsies from healthy, freeranging individuals are preferred to samples from stranded animals. Further research on the influence of factors (age, sex, reproductive condition, diet) that potentially affect retinoid levels is required to implement the use of retinoids as biomarkers of pollutant exposure in cetaceans.

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Section: Discussionsupporting

confidence: 75%

Section: Discussioncontrasting

confidence: 39%

Section: Discussionmentioning

confidence: 55%

Section: Discussionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Tissue distribution of retinoids in common dolphins Delphinus delphis

Tornero

Borrell²,

Forcada³

et al. 2004

Mar. Ecol. Prog. Ser.

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Determination of vitamins D, A, and E in sera and vitamin D in milk from captive and free-ranging polar bears (Ursus maritimus), and 7-dehydrocholesterol levels in skin from captive polar bears

et al. 1998

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The difference between serum levels from 36 captive and 56 free‐ranging polar bears (Ursus maritimus) for 25‐hydroxyvitamin D (25‐OH‐D) was found not to be significant (mean ± SD = 348 ± 215 nmol/L [captive], 360 ± 135 nmol/L [free‐ranging], t = 0.30, df = 52.8, P = 0.76), whereas the difference for retinol and α‐tocopherol was significant (retinol, 1.37 ± 0.67 μmol/L [captive] 1.89 ± 0.63 μmol/L [free‐ranging], t = 3.88, df = 72.4, P <0.001, α‐tocopherol, 18.56 ± 18.56 μmol/L [captive], 48.76 ± 13.92 μmol/L [free‐ranging], t = 7.85, df = 61.9, P < 0.001). Due to the high fat content in the polar bear diet, seal blubber may be the source of these fat‐soluble vitamins. Six skin biopsies were analyzed from captive polar bears at the Denver Zoological Gardens for 7‐dehydrocholesterol levels and found to contain 0.11 ± 0.03 nmol/cm2. This finding also helps to support the contention that the source of vitamin D for polar bears may be ingestion and not cutaneous production. Vitamin D content in the milk from one captive sow in the den (0.14 nmol/g) and 10 free‐ranging sows with cubs of the year out on the ice pack (0.0042 ± 0.0073 nmol/g) were also evaluated. It would be helpful to evaluate additional milk samples from denning and non‐denning sows with cubs to see whether vitamin D content varies according to the stage of lactation. Zoo Biol 17:285–293, 1998. © 1998 Wiley‐ Liss, Inc.

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Accumulation of Vitamin A in the Hepatic Stellate Cell of Arctic Top Predators

Senoo

Imai

Mezaki

et al. 2012

The Anatomical Record

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We performed a systematic characterization of the hepatic vitamin A storage in mammals and birds of the Svalbard Archipelago and Greenland. The liver of top predators, including polar bear, Arctic fox, bearded seal, and glaucous gull, contained about 10-20 times more vitamin A than the liver of all other arctic animals studied, as well as their genetically related continental top predators. The values are also high compared to normal human and experimental animals like mouse and rat. This massive amount of hepatic vitamin A was located in large autofluorescent lipid droplets in hepatic stellate cells (HSCs; also called vitamin A-storing cells, lipocytes, interstitial cells, fat-storing cells, or Ito cells). The droplets made up most of the cells' cytoplasm. The development of such an efficient vitamin A-storing mechanism in HSCs may have contributed to the survival of top predators in the extreme environment of the arctic. These animals demonstrated no signs of hypervitaminosis A. We suggest that HSCs have capacity to take-up and store large amounts of vitamin A, which may play a pivotal role in maintenance of the food web, food chain, biodiversity, and eventually ecology of the arctic.

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Vitamin A in seals

Cited by 26 publications

References 2 publications

Tissue distribution of retinoids in common dolphins Delphinus delphis

Tissue distribution of retinoids in common dolphins Delphinus delphis

Determination of vitamins D, A, and E in sera and vitamin D in milk from captive and free-ranging polar bears (Ursus maritimus), and 7-dehydrocholesterol levels in skin from captive polar bears

Accumulation of Vitamin A in the Hepatic Stellate Cell of Arctic Top Predators

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