Changes in adipopnectin, leptin, and fat mass after clenbuterol treatment in horses.

The research paper investigates how the use of the drug clenbuterol, with or without exercise, affects levels of adiponectin and leptin – two key hormones involved in regulating body fat and energy metabolism – in horses. The results indicate that chronic clenbuterol treatment can alter these hormone levels and potentially affect fat distribution in the animal.

Objective and Methodology

Given the complex roles of adipose tissue in metabolic and endocrine balance, the researchers conducted this study to measure the effects of clenbuterol, exercise, or both on adipocytokine concentrations in horses. The research involved:

• 23 standard-bred mares separated into four groups: clenbuterol plus exercise (CLENEX), clenbuterol only (CLEN), exercise only (EX), and control (CON).
• Administering clenbuterol (2.4 microg.kg(-1) body weight twice daily for eight weeks) and/or implementing a regimented exercise program (20 minutes per day at 50% VO2max for eight weeks).
• Measuring rump fat thickness using B-mode ultrasound and calculating the percentage body fat.
• Assessing plasma concentrations of adiponectin and leptin through radioimmunoassay (RIA), with results expressed as human equivalents due to the lack of purified equine adiponectin or leptin.

Key Findings

The researchers analyzed the link between changes in adiponectin and leptin levels and changes in fat and fat-free mass, revealing that:

• The change in adiponectin concentration was negatively correlated with the change in fat mass and positively correlated with the change in fat-free mass.
• The change in leptin concentration showed a positive correlation with the change in fat mass and a negative correlation with the change in fat-free mass.

Conclusions

The findings show that chronic administration of clenbuterol can alter adiponectin and leptin concentrations in horses. The changes to these hormone levels could be involved in the previously reported repartitioning effects of clenbuterol, whereby fat and lean body mass quantities are redistributed within the body. Thus, clenbuterol may have a significant impact on the body composition and metabolic parameters of treated horses.