Fig. 2.

Ultrastructural and immunocytochemical features of the postadipocyte pericellular matrix. (A) Postadipocytes from rats infused for 14 days with leptin adenovirus are surrounded by a very thick layer of finely granular material (asterisks) that separates them from the collagen fibrils of the interstitial matrix. (B) Immunocytochemical localization of collagen type IV in control epididymal fat pad tissue. Immunoreactivity is detected as a thin, faint line surrounding each individual adipocyte and corresponding to the location of the basal lamina. (C) Four days after the infusion of leptin adenovirus, adipocytes still present a spheroidal shape, but their size has decreased. Collagen IV staining at the cell periphery appears considerably thicker than in control rats. (D) After 14 days of hyperleptinemia, adipocytes are further reduced in size, and their highly indented surface displays a thick, scalloped collagen IV immunoreactivity.