Circulating leptin levels are modulated by fasting, cold exposure and insulin administration in lean but not Zucker (fa/fa) rats as measured by ELISA

Biochem Biophys Res Commun. 1996 Jun 25;223(3):660-5. doi: 10.1006/bbrc.1996.0951.


The development of a sensitive enzyme-linked immunosorbent assay (ELISA) is described for the quantitation of plasma leptin levels in both mice and rats. Approximately 1.5 ng leptin/ml plasma was detected in lean mice but significantly (p < 0.01) less was found in the plasma of ob/ob mice. In lean Zucker rats leptin circulated at approximately 4ng/ml plasma whereas levels were elevated more than 6-fold in fa/fa rats. Circulating leptin levels declined (p < 0.05) in lean rats which were fasted or exposed to 4 degrees C for 24h, but subsequently recovered to normal within 12h of refeeding or warming, respectively. Administration of insulin increased leptin levels in lean rats within 4h (p < 0.01). However, leptin levels were unchanged in fa/fa rats exposed to the same physiological stimuli.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acclimatization*
  • Animals
  • Cold Temperature
  • Eating
  • Enzyme-Linked Immunosorbent Assay
  • Fasting*
  • Insulin / pharmacology*
  • Leptin
  • Male
  • Mice
  • Mice, Obese
  • Obesity / blood*
  • Proteins / analysis
  • Proteins / drug effects
  • Proteins / metabolism*
  • Rats
  • Rats, Zucker
  • Thinness


  • Insulin
  • Leptin
  • Proteins