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Changes in Leptin and Insulin Blood Concentration in Short Term and Long Term Fasting
Author(s) -
Franklin Tina Carla,
Florant Gregory
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a297
Subject(s) - leptin , medicine , insulin , endocrinology , hormone , biology , adipose tissue , glycogen , obesity , glycogenesis , glycogen synthase
Obesity is a rising epidemic and the source of many health problems including cardiovascular diseases and Type II diabetes. Body weight regulation is widely studied and two specific hormones, leptin and insulin, are involved in body weight and food intake regulation. Leptin, produced and released by adipocytes, increases as adipose size increases in the body. Insulin, produced and released by the pancreatic β cell and known for its role in blood glucose homeostasis, has been found to be involved in the regulation of leptin. Low insulin levels stimulate lipid and glycogen breakdown during fasting. The golden mantle ground squirrel ( Spermophilus lateralis ), hibernates from October to May and doubles its body mass before hibernation to survive the winter. We hypothesized that blood leptin and insulin concentrations decrease the longer the fast during the summer because of decreasing blood glucose levels in the lean animals. We also hypothesized that during the winter, blood leptin and insulin concentration should be low. In this experiment, we measured blood leptin and insulin levels during different fasting periods using rat/mouse insulin and leptin ELISA kits. Leptin and insulin blood levels were extremely low in the short term fasted animals, however neither hormone levels significantly dropped in the hibernating animals. This suggests that during short term fast in the summer these hormones primarily regulate food intake; during long term fast in the winter the hormones primarily regulate lipid oxidation and glycogenesis. NIH NIDDK GRANT R25DK067017‐02, Colorado State University NIH NIGMS MBRS RISE Grant 5R25 GM059244‐05, Barry University.