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Bile constituents in hibernating golden-mantled ground squirrels (Spermophilus lateralis).

Baker JA, van Breukelen F - Comp Hepatol (2009)

Bottom Line: Surprisingly, hibernator bile did not differ from summer squirrel bile in key characteristics including [bile acids], [cholesterol], [free fatty acids], [lecithin], and osmolality.Animals that failed to hibernate, despite being anorexic, were very similar to summer squirrels in all measured parameters except they had lower bile acid and lecithin concentrations.The data indicate that despite extended anorexia, differences in metabolic fuel privation, and bouts of reduced body temperatures, hibernators normally do not experience broad changes in hepatobiliary function.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Life Sciences, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas Nevada 89154 USA. abaker1170@aol.com

ABSTRACT

Background: Golden-mantled ground squirrels (S. lateralis) are anorexic during the winter and survive by exploiting hibernation to reduce energetic demands. The liver normally plays a critical role in fueling and regulating metabolism and one might expect significant changes in hepatobiliary function with hibernation. We analyzed bile collected from animals in summer, animals in winter that were either torpid, active between bouts of torpor, or which failed to enter hibernation in order to characterize the effects of hibernation on hepatobiliary function per se.

Results: Surprisingly, hibernator bile did not differ from summer squirrel bile in key characteristics including [bile acids], [cholesterol], [free fatty acids], [lecithin], and osmolality. One major distinction between summer and winter squirrels was that winter squirrels experience >5 fold increases in [bilirubin]. Such an increase may have significant physiological consequences that could aid in survivorship of torpor. Animals that failed to hibernate, despite being anorexic, were very similar to summer squirrels in all measured parameters except they had lower bile acid and lecithin concentrations.

Conclusion: The data indicate that despite extended anorexia, differences in metabolic fuel privation, and bouts of reduced body temperatures, hibernators normally do not experience broad changes in hepatobiliary function.

No MeSH data available.


Related in: MedlinePlus

Bile constituents as a function of hibernation state. A) Bile lecithin/phosphatidylcholine concentration as a function of state. Values represent means ± SE from T (n = 3), IBA (n = 3), SA (n = 3), and AB squirrels (n = 4). AB was significantly lower than all other states (ANOVA, p < 0.05). When different, letters above error bars denote significant differences. B) Bile osmolality as a function of state. Values represent means ± SE from T (n = 6), IBA (n = 3), SA (n = 11), and AB squirrels (n = 4). There were no significant differences (ANOVA, p > 0.05). C) pH of bile measured at 37°C as a function of state. Values represent means ± SE from T (n = 4), IBA (n = 4), SA (n = 10), and AB squirrels (n = 4). All values are significantly different except between T and IBA (ANOVA, p > 0.05). D) Total protein concentration in bile as a function of state. Values represent means ± SE from T (n = 3), IBA (n = 3), SA (n = 5), and AB squirrels (n = 4). There were no significant differences between T and IBA or between SA and AB. All other values are significantly different (ANOVA, p < 0.05).
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Figure 3: Bile constituents as a function of hibernation state. A) Bile lecithin/phosphatidylcholine concentration as a function of state. Values represent means ± SE from T (n = 3), IBA (n = 3), SA (n = 3), and AB squirrels (n = 4). AB was significantly lower than all other states (ANOVA, p < 0.05). When different, letters above error bars denote significant differences. B) Bile osmolality as a function of state. Values represent means ± SE from T (n = 6), IBA (n = 3), SA (n = 11), and AB squirrels (n = 4). There were no significant differences (ANOVA, p > 0.05). C) pH of bile measured at 37°C as a function of state. Values represent means ± SE from T (n = 4), IBA (n = 4), SA (n = 10), and AB squirrels (n = 4). All values are significantly different except between T and IBA (ANOVA, p > 0.05). D) Total protein concentration in bile as a function of state. Values represent means ± SE from T (n = 3), IBA (n = 3), SA (n = 5), and AB squirrels (n = 4). There were no significant differences between T and IBA or between SA and AB. All other values are significantly different (ANOVA, p < 0.05).

Mentions: Lecithin or phosphatidylcholine was significantly lower in the AB group as compared to all other squirrels (Fig. 3A). A major function of lecithin is in the excretion of cholesterol during normal metabolism [13]. Osmolality was unchanged as a function of state (Fig. 3B). Torpor state had a significant effect on pH (Fig. 3C). Bile from winter hibernators (T and IBA) was significantly more acidic than either SA or AB bile. Indeed, hibernator bile had over 10 fold higher H+ concentration than AB bile (> 1.2 pH units). Bile protein concentration was significantly different as a result of state: hibernators (T and IBA) had approximately 5 fold higher protein levels than their AB counterparts (Fig. 3D). AB animals were more similar to SA squirrels.


Bile constituents in hibernating golden-mantled ground squirrels (Spermophilus lateralis).

Baker JA, van Breukelen F - Comp Hepatol (2009)

Bile constituents as a function of hibernation state. A) Bile lecithin/phosphatidylcholine concentration as a function of state. Values represent means ± SE from T (n = 3), IBA (n = 3), SA (n = 3), and AB squirrels (n = 4). AB was significantly lower than all other states (ANOVA, p < 0.05). When different, letters above error bars denote significant differences. B) Bile osmolality as a function of state. Values represent means ± SE from T (n = 6), IBA (n = 3), SA (n = 11), and AB squirrels (n = 4). There were no significant differences (ANOVA, p > 0.05). C) pH of bile measured at 37°C as a function of state. Values represent means ± SE from T (n = 4), IBA (n = 4), SA (n = 10), and AB squirrels (n = 4). All values are significantly different except between T and IBA (ANOVA, p > 0.05). D) Total protein concentration in bile as a function of state. Values represent means ± SE from T (n = 3), IBA (n = 3), SA (n = 5), and AB squirrels (n = 4). There were no significant differences between T and IBA or between SA and AB. All other values are significantly different (ANOVA, p < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2692966&req=5

Figure 3: Bile constituents as a function of hibernation state. A) Bile lecithin/phosphatidylcholine concentration as a function of state. Values represent means ± SE from T (n = 3), IBA (n = 3), SA (n = 3), and AB squirrels (n = 4). AB was significantly lower than all other states (ANOVA, p < 0.05). When different, letters above error bars denote significant differences. B) Bile osmolality as a function of state. Values represent means ± SE from T (n = 6), IBA (n = 3), SA (n = 11), and AB squirrels (n = 4). There were no significant differences (ANOVA, p > 0.05). C) pH of bile measured at 37°C as a function of state. Values represent means ± SE from T (n = 4), IBA (n = 4), SA (n = 10), and AB squirrels (n = 4). All values are significantly different except between T and IBA (ANOVA, p > 0.05). D) Total protein concentration in bile as a function of state. Values represent means ± SE from T (n = 3), IBA (n = 3), SA (n = 5), and AB squirrels (n = 4). There were no significant differences between T and IBA or between SA and AB. All other values are significantly different (ANOVA, p < 0.05).
Mentions: Lecithin or phosphatidylcholine was significantly lower in the AB group as compared to all other squirrels (Fig. 3A). A major function of lecithin is in the excretion of cholesterol during normal metabolism [13]. Osmolality was unchanged as a function of state (Fig. 3B). Torpor state had a significant effect on pH (Fig. 3C). Bile from winter hibernators (T and IBA) was significantly more acidic than either SA or AB bile. Indeed, hibernator bile had over 10 fold higher H+ concentration than AB bile (> 1.2 pH units). Bile protein concentration was significantly different as a result of state: hibernators (T and IBA) had approximately 5 fold higher protein levels than their AB counterparts (Fig. 3D). AB animals were more similar to SA squirrels.

Bottom Line: Surprisingly, hibernator bile did not differ from summer squirrel bile in key characteristics including [bile acids], [cholesterol], [free fatty acids], [lecithin], and osmolality.Animals that failed to hibernate, despite being anorexic, were very similar to summer squirrels in all measured parameters except they had lower bile acid and lecithin concentrations.The data indicate that despite extended anorexia, differences in metabolic fuel privation, and bouts of reduced body temperatures, hibernators normally do not experience broad changes in hepatobiliary function.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Life Sciences, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas Nevada 89154 USA. abaker1170@aol.com

ABSTRACT

Background: Golden-mantled ground squirrels (S. lateralis) are anorexic during the winter and survive by exploiting hibernation to reduce energetic demands. The liver normally plays a critical role in fueling and regulating metabolism and one might expect significant changes in hepatobiliary function with hibernation. We analyzed bile collected from animals in summer, animals in winter that were either torpid, active between bouts of torpor, or which failed to enter hibernation in order to characterize the effects of hibernation on hepatobiliary function per se.

Results: Surprisingly, hibernator bile did not differ from summer squirrel bile in key characteristics including [bile acids], [cholesterol], [free fatty acids], [lecithin], and osmolality. One major distinction between summer and winter squirrels was that winter squirrels experience >5 fold increases in [bilirubin]. Such an increase may have significant physiological consequences that could aid in survivorship of torpor. Animals that failed to hibernate, despite being anorexic, were very similar to summer squirrels in all measured parameters except they had lower bile acid and lecithin concentrations.

Conclusion: The data indicate that despite extended anorexia, differences in metabolic fuel privation, and bouts of reduced body temperatures, hibernators normally do not experience broad changes in hepatobiliary function.

No MeSH data available.


Related in: MedlinePlus