BLACK BEAR (URSUS-AMERICANUS) BILE COMPOSITION - SEASONAL-CHANGES

Gallbladder contents from 8 active and 14 dormant black bears were ana lyzed for individual bile acids by high-performance liquid chromatogra phy and for cholesterol, phospholipids, sodium, potassium, calcium, ma gnesium, zinc, iron, and copper. Only three bile acids occurring as ta urine conjugates were detected: tauroursodeoxycholate, taurochenodeoxy cholate, and taurocholate. The proportion of tauroursodeoxycholate to the sum of the three bile acids decreased. Calcium, cholesterol, phosp holipids, magnesium, zinc, and copper concentrations were increased in dormancy. Standardized collection and handling procedures yielded mor e consistent data than previously available. The decrease in taurourso deoxycholate and absence of deoxycholate and lithocholate are consiste nt with our working hypothesis that a marked reduction in metabolic ac tivity of the gut flora is an integral part of the adaptation to metab olic stability of the dormant bear. (C) 1997 Elsevier Science Inc.