Adiponectin/Acrp30, an adipocyte-specific secretory factor: physiological relevance during development

Adiponectin/Acrp30 is a fat cell-specific secretory product. The convergence of results from epidemiological, pharmacological and genetic studies over the last 2 yr has highlighted the important role that this multimeric protein complex plays in the context of insulin sensitivity. While the exact mechanism of action has not been elucidated, it is clear that adiponectin has insulin-sensitizing effects on both liver and muscle. The important role that adipose tissue plays in energy homeostasis as a storage compartment for triglycerides has been appreciated for a long time. The identification of leptin as a key hormone involved in central control of energy metabolism suggested that adipocytes also use polypeptide hormones to influence metabolic processes at distant sites. The recent progress made towards the characterization of the physiological role of adiponectin highlights the important role of adipose tissue as an endocrine organ and its central role in the fine-tuning of hepatic and muscle insulin responsiveness.