Annual Changes in Serum Leptin Concentration in the Adult Female Japanese Black Bear (Ursus thibetanus japonicus)

Tsubota, Toshio; Sato, Miho; Okano, Tsukasa; Nakamura, Sachiko; Asano, Makoto; Komatsu, Takeshi; Shibata, Haruki; Saito, Masayuki

doi:10.1292/jvms.70.1399

Cited by 42 publications

(10 citation statements)

References 33 publications

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“…Although the mechanism of puberty in bears is still not entirely clear (WHITE et al, 2005;TSUBOTA et al, 2008), it should follow some of the patterns already described for S. Reljić et al: Reproductive span in captive brown bears other species of wild mammals. In order to study the mechanism involved, it is crucial to determine the timing of the first ovulation and at the same time analyse endogenous and exogenous stimuli present.…”

Section: Introductionmentioning

confidence: 63%

Determination of reproductive span through morpho-histological studies on the ovaries of captive brown bears (Ursus arctos) - a short communication

et al. 2019

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HuBeR: Determination of reproductive span through morpho-histological studies on the ovaries of captive brown bears (Ursus arctos) -a short communication. vet. arhiv 89, 233-246, 2019. ABSTRAcTThe study aimed to determine reproductive span by investigation of the ovarian structures in young and elderly captive brown bear females (Ursus arctos). The ovaries of two 2-year-old females were obtained by ovariectomy and during the necropsies of 31 and 36 year old individuals. All the obtained ovaries were examined macroscopically and histologically. Histological examination of the ovaries of young animals (2+ years) revealed the presence of primordial, primary, secondary and tertiary follicles within the ovarian S. Reljić et al.: Reproductive span in captive brown bears cortex. One ovary showed a mature corpus luteum, indicating recent ovulation, what is, to our knowledge, the first histological proof of the earliest age of ovulation recorded for captive brown bears. Ovarian atrophy accompanied by the development of multiple cystic subsurface epithelial structures (SES) in the case of the old bears in this study indicates that the ovaries of brown bears share similar degenerative and proliferative patterns with domestic canids. The oldest female had records of successful births at the ages of 26 and 28 years. Both recorded birth events represent one of the latest confirmed occurrences of ovulation, conception and birth amongst brown bears.

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Section: Introductionmentioning

confidence: 63%

Determination of reproductive span through morpho-histological studies on the ovaries of captive brown bears (Ursus arctos) - a short communication

et al. 2019

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“…The newly established canine leptin‐specific ELISA kit, which utilizes the anti‐dog leptin antibody, had been previously confirmed as useful for determining blood leptin concentrations of dogs, cats ( Felis catus ), raccoons ( Procyon lotor ), and bears ( Ursus thibetanus japonicus ) (Shibata et al, 2005; Tsubota et al, 2008). The raccoon dog is a member of Canidae and is closely related to dogs (Ward and Wurster‐Hill, '90).…”

Section: Discussionmentioning

confidence: 99%

“…The circulating leptin level is thus well correlated with body weight, and more precisely, the overall body fat content (Frederich et al, '95; Maffei et al, '95; Sagawa et al, 2002). In wild animals, various attempts have been made to use leptin as a marker for long‐term nutritional condition and body adiposity (Mustonen et al, 2005; Shibata et al, 2005; Soppela et al, 2008; Tsubota et al, 2008; Gaspar‐López et al, 2009). Annual cycles of food intake and adiposity are associated with significant seasonal changes in circulating leptin concentrations and altered leptin gene expression in the adipose tissues of some seasonal mammals, such as Siberian hamsters ( Phodopus sungorus ; Rousseau et al, 2003).…”

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confidence: 99%

Seasonality and fasting effect in raccoon dog Nyctereutes procyonoides serum leptin levels determined by canine leptin‐specific enzyme‐linked immunosorbent assay

et al. 2010

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Leptin is an adipocyte-derived peptide hormone that acts on the brain and regulates food intake and energy balance. Several previous reports have suggested that overwintering raccoon dogs Nyctereutes procyonoides are able to control their adiposity efficiently, but the contribution of leptin to weight regulation in these animals remains unclear. To study the seasonality of overwintering raccoon dogs as well as the effects of fasting on them, serum leptin levels were investigated using a newly established canine leptin-specific enzyme-linked immunosorbent assay (ELISA) kit. Of the nine animals studied, five were fed and four were fasted (deprived of food for 2 months in winter). Blood samples and body fat weights were monitored once a month throughout the experimental period (July 2007-March 2008). Leptin concentrations obtained by ELISA were significantly higher than and had a positive correlation with those obtained by previously used multispecies radioimmunoassay (RIA) kits. Moreover, ELISA showed a clearer correlation between the body fat weight and leptin levels compared with RIA, suggesting the efficacy of canine leptin-specific ELISA kit for leptin estimation in raccoon dogs. Autumnal fattening was observed in both groups of animals, but the wintertime loss of adipose tissue was more obvious in the fasted group. Serum leptin concentrations determined by ELISA showed seasonal changes without significant differences between the fed and fasted animals. Therefore, high levels of leptin may be responsible for the suppression of feeding behavior in raccoon dogs before winter.

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“…Tøien et al (2011) documented a reduction in metabolism during hibernation to 25 % of basal rates independent of lowered body temperature, suggesting other endogenous factors may be involved in triggering the physiological changes accompanying hibernation. Studies of the processes regulating hibernation revealed a higher proportion of plasma unsaturated fatty acids during winter than during summer months, and increased leptin concentrations directly before hibernation corresponding to maximal fat content (Hissa et al 1998;Tsubota et al 2008). …”

Section: Plin2mentioning

confidence: 99%

“…Because fat serves such an important function in hibernators, it is essential to understand how fat-borne signals are utilized by the body, and conversely, how fat cells respond to metabolic cues. Two adipocyteproduced hormones, leptin and adiponectin, vary seasonally in several Ursus species with peaks occurring just prior to hibernation (Hill 2013;Hissa et al 1998;Tsubota et al 2008). However, the role of these adipokines in hibernation and in seasonal fat metabolism has yet to be firmly established.…”

Section: Introductionmentioning

confidence: 99%

A protocol for the isolation and cultivation of brown bear (Ursus arctos) adipocytes

et al. 2016

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Brown bears (Ursus arctos) exhibit hyperphagia each fall and can become obese in preparation for hibernation. They do this without displaying the physiological problems typically seen in obese humans, such as Type 2 diabetes and heart disease. The study of brown bear hibernation biology could therefore aid in the development of novel methods for combating metabolic diseases. To this end, we isolated mesenchymal stem cells from subcutaneous fat biopsies, and culture methods were developed to differentiate these into the adipogenic lineage. Biopsies were taken from 8 captive male (N = 6) and female (N = 2) brown bears, ages 2-12 years. Plastic adherent, fibroblast-like cells were proliferated and subsequently cryopreserved or differentiated. Differentiation conditions were optimized with respect to fetal bovine serum content and time spent in differentiation medium. Cultures were characterized through immunostaining, RT-qPCR, and Oil red O staining to quantify lipid accumulation. Adiponectin, leptin, and glycerol medium concentrations were also determined over the course of differentiation. The culturing protocol succeeded in generating hormone-sensitive lipase-expressing, lipid-producing white-type adipocytes (UCP1 negative). Serum concentration and time of exposure to differentiation medium were both positively related to lipid production. Cells cultured to low passage numbers retained similar lipid production and expression of lipid markers PLIN2 and FABP4. Ultimately, the protocols described here may be useful to biologists in the field investigating the health of wild bear populations and could potentially increase our understanding of metabolic disorders in humans.

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Annual Changes in Serum Leptin Concentration in the Adult Female Japanese Black Bear (Ursus thibetanus japonicus)

Cited by 42 publications

References 33 publications

Determination of reproductive span through morpho-histological studies on the ovaries of captive brown bears (Ursus arctos) - a short communication

Determination of reproductive span through morpho-histological studies on the ovaries of captive brown bears (Ursus arctos) - a short communication

Seasonality and fasting effect in raccoon dog Nyctereutes procyonoides serum leptin levels determined by canine leptin‐specific enzyme‐linked immunosorbent assay

A protocol for the isolation and cultivation of brown bear (Ursus arctos) adipocytes

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