Diabetes & Obesity

Serum, heparin and EDTA plasma, urine, saliva, cell culture.

Normal food intake rhythm provided, samples should be collected till 2 p.m. Leptin shows a moderate circadian variation with a peak at 2 a.m., the leptin values at that time are about 30 to 100 % higher.
This variation together with the influence of food intake needs to be taken into account when blood samples are collected. Whole blood should be refrigerated as soon as possible following collection.
Samples are stable for maximal 2 days at room temperature.
Long-term storage stable for maximal 2 years at -20 °C.
Max. 5 freeze and thaw cycles.

Leptin levels depend on age and gender and must be referred to the percentage body fat (such as BMI).
Comprehensive clinical reference data are available for this test.

Human

Leptin, the product of the ob gene, is a recently discovered proteohormone. It is almost exclusively produced by differentiated adipocytes and is thought to play a key role in the regulation of body weight. Leptin has an influence on the central nervous system, mainly on the hypothalamus, by suppressing food ingestion and increasing energy consumption.
Beside its influence on food intake, leptin has been shown to have a strong effect on reproduction and a number of metabolic and endocrine axes.
As leptin is of great importance for reproductive functions, infertility may be due to inadequate leptin production. The most important variable determining the circulating leptin concentration is the body fat mass as leptin level and fat mass increase exponentially. Due to its pleiotropic effects, leptin is a valuable parameter with regard to:

• Metabolic syndrome
• Adiposity
• Cachexia and other metabolic disorders
• Eating disorders