C - Michigan Technological University

factors Runx2 and OCN also increase in osteoblasts differentiated in post-hibernationserum, further supporting the idea of increased osteoblast activity in this season.In summary, the gene expression studies suggest that factors circulating in bearsin the weeks immediately following hibernation promote a hypermetabolic state inosteoblasts. Differentiated osteoblasts have higher expression of ubiquitin anddifferentiation markers, suggesting active protein metabolism and bone formation duringpost-hibernation. Undifferentiated osteoblasts have higher expression of Akt and CyclinD1, suggesting active proliferation of osteoblasts during post-hibernation. These data fitan earlier report of high bone turnover rate in spring-time bears [35].6.5 Tables and figuresTable 6.1—Summary of assaysThe number of bears and assays that were performed in each hibernation season. Thenumber of bears that gave birth to cubs is in parentheses. Unknown values are indicated as“UK.” Assays in undifferentiated cells are labeled “UD,” and assays in differentiated cells arelabeled “D.”Season BearsAge(years)AssaysData Location2006‐2007 2 (1) UK 3hr UD, 3hr D, 24hr UD, 6 day D Table 6.2‐6.52007‐2008 4 (3) 5‐14 24hr UD Table 6.497