Related Experiment Video
Updated: May 30, 2026
05:45
Experimental Approach to Examine Leptin Signaling in the Carotid Bodies and its Effects on Control of Breathing
Published on: October 25, 2019
Leptin-programmed rats respond to cold exposure changing hypothalamic leptin receptor and thyroid function
Sheila Cristina Potente Dutra1, Egberto Gaspar de Moura, Patricia Cristina Lisboa
1Department of Nutrition, Federal University of Juiz de Fora, Minas Gerais, MG, Brazil.
Regulatory Peptides
|August 2, 2011
Summary
Neonatal leptin exposure programs adult metabolic changes. Acute cold exposure in adult rats normalized most programmed alterations, but worsened hyperthyroidism and brown adipose tissue function.
Area of Science:
- Endocrinology
- Metabolic Regulation
- Environmental Physiology
Background:
- Neonatal leptin administration can program long-term metabolic and endocrine alterations into adulthood.
- Previous studies indicated that acute cold exposure in young rats could normalize leptin signaling and thyroid function.
- The impact of cold exposure on adult metabolic and thyroid parameters programmed by neonatal hyperleptinemia remains unclear.
Purpose of the Study:
- To investigate the effects of acute cold exposure on thyroid hormones, leptin signaling, and related metabolic markers in adult rats neonatally programmed with hyperleptinemia.
- To determine if cold exposure can reverse the detrimental metabolic programming induced by early-life leptin excess.
Main Methods:
- Neonatal rats received leptin or saline injections for the first 10 days of lactation.
- At adulthood (150 days), rats were exposed to acute cold (8°C for 12 hours) or kept at thermoneutrality.
- Measurements included serum leptin, thyroid hormones (T4, T3), TSH, deiodinase activities (D1, D2), liver mitochondrial GPD, adrenal catecholamines, and hypothalamic/thyroid OBR protein.
Main Results:
- Neonatal leptin programming resulted in adult hyperleptinemia, elevated thyroid hormones, suppressed TSH, altered deiodinase activities, reduced liver mGPD, increased adrenal catecholamines, and decreased hypothalamic OBR.
- Cold exposure normalized leptinemia, D1 activity, mGPD, catecholamines, and hypothalamic OBR.
- However, cold exposure exacerbated hyperthyroidism (increased TH) and reduced BAT D2 activity.
Conclusions:
- Acute cold exposure effectively reverses most metabolic and hormonal dysregulations programmed by neonatal hyperleptinemia in adult rats.
- The beneficial effects of cold exposure come at the cost of worsening thyroid hormone levels and impairing brown adipose tissue thermogenic capacity.
- These findings highlight a complex interplay between early-life programming, environmental stimuli, and metabolic adaptation.
Related Concept Videos
02:45Responses to Heat and Cold Stress
Every organism has an optimum temperature range within which healthy growth and physiological functioning can occur. At the ends of this range, there will be a minimum and maximum temperature that interrupt biological processes.
01:26Thermoregulation
The human body has a sophisticated thermoregulation system that employs negative feedback mechanisms to maintain an optimal core temperature. When the core temperature drops, peripheral and central thermoreceptors send signals to the hypothalamus, activating the heat-promoting center. This center triggers several responses aimed at increasing the core temperature. First, vasoconstriction reduces the flow of warm blood from internal organs to the skin so that the heat is not lost from the skin,...