Leptin expression during the differentiation of subcutaneous adipose cells of human embryos in situ.

In this study, the immunocytochemical expression of leptin in the developing subcutaneous tissue of human embryos at 6-10 weeks of gestation was investigated using the avidin-biotin peroxidase method. Immunocytochemical staining for leptin was observed in the cytoplasm of the differentiating preadipose cells. The other cells present in the embryonal subcutis (mesenchymal cells differentiating into fibroblasts, fibrocytes, endothelial cells) were leptin-negative. The developing skin epithelium lying above it and the blood cells in the capillaries also did not express leptin. The results suggest that the leptin is produced by the developing fat cells from the beginning of lipidogenesis and differentiation. It possibly acts as a hormonal factor regulating the embryonal growth, development and body fat storage. Copyright 2000 S. Karger AG, Basel