A Seasonal Comparison of Leptin levels in Bone marrow adipocytes, Blood, and Cerebrospinal fluid in Golden-Mantled Ground Squirrels (Callopermophilus lateralis) and Yellow-Bellied Marmots (Marmota flaviventris


Meeting Abstract

P3-97  Saturday, Jan. 6 15:30 – 17:30  A Seasonal Comparison of Leptin levels in Bone marrow adipocytes, Blood, and Cerebrospinal fluid in Golden-Mantled Ground Squirrels (Callopermophilus lateralis) and Yellow-Bellied Marmots (Marmota flaviventris. MERRELL, EA*; ALLYN, V; MULAWA, EA; DONAHUE, SW; FLORANT, GL; Colorado State University; Colorado State University; Colorado State University; Colorado State University; Colorado State University eamerrel@rams.colostate.edu

Hibernation is a process used by some mammals to survive prolonged periods of cold temperatures and lack of food. In preparation, these animals dramatically increase their fat stores, in the form of white adipose tissue (WAT), from summer to autumn. Hibernators stop eating and do not lose bone mass during the hibernation period. Instead, they rely on endogenous energy from WAT during this time. Leptin, a satiety hormone secreted primarily from WAT, has been shown to be involved in the regulation of food intake, body mass, and perhaps bone metabolism. Leptin has been measured seasonally in the blood of several hibernating species, including bears (Ursus), bats (Cynopterus), marmots (Marmota), and ground squirrels (Callopermophilus). High blood leptin concentrations during pre-hibernation period were reported across these species, and decreased during the late hibernation season. We sought to gain a better understanding of how these findings compared to the concentration of leptin in other tissue types seasonally in a hibernator. Using a radioimmunoassay (RIA) for leptin, we measured pre-hibernation, hibernation, post-hibernation and summer seasonal concentrations in serum, cerebrospinal fluid (CSF), and tibial bone marrow adipocytes (BMA) of marmots. Using the same RIA, we measured seasonal leptin concentrations in plasma, CSF, and femoral BMA of ground squirrels. We hypothesized that the concentration of leptin in CSF and BMA would not vary with a specific season, however we hypothesized that serum and plasma concentrations would be higher in pre-hibernation and hibernation compared to post-hibernation and summer groups.

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