Fig. 2.
Adipose tissue as the only detectable source of leptin. (A) Genomic organization of the Leptin locus and structure of the targeting vector. Probes used for Southern blots and restriction fragments are indicated. (B) Southern blots. The WT and lacZ knock-in loci gave, respectively, 15.0- and 6.2-kb bands with the 3′ probe, and 15.1- and 9.1 kb bands with the 5′ probe. E, EcoRI; K, KpnI. (C and D) X-Gal-stained gonadal adipose tissue and brain. Staining was detected exclusively in adipose tissue in LepLacZ/LacZ mice. No staining was detected in brain. (E and F) Histological examination of adipose and brain tissues after X-Gal staining. Nuclear staining was readily detectable in adipocyte nuclei, but no staining was observed in any brain section. A representative brain section containing arcuate and ventromedial hypothalamus neurons counterstained with Hoescht (Left) and stained with X-Gal (Right) are shown.