ZFIN Image: Löhr et al., 2018, Fig. 2

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Figure Caption

Fig. 2

Long-Term Overfeeding Causes Leptin Resistance and Has an Impact on Both the Melanocortin and GH Systems

(A) qRT-PCR analyses of mRNA levels for gh1, pomca, agrp, trh, oxt, and crh. Corticotropin-releasing hormone (Dhillo et al., 2002) (crh) was downregulated in the HD group, but not in the HD/HF group, possibly pointing to stress responses caused by incubation in egg yolk medium. To specifically assess hypothalamic pomca expression levels, the pituitary was removed in pomca (−pit).

(B) Number of Pomca neurons in three feeding groups as determined by anti-GFP IF and cell counts in pomca:EGFPras fish (see Figure 3; n = 10).

(C) mRNA levels of gh1, pomca, and agrp after short-term application of egg yolk to 14 dpf larvae.

(D–F) IF for GFP and pERK on an exemplary pomca:EGPras transgenic larval brain (see Figure 3) subjected to the LD feeding regimen and incubated in saline.

(D) Overview of hypothalamic regions with GFP+/pERK+ domains.

(E and F) Magnification of areas boxed in (D) revealing GFP+/pERK+ cells (E, arrowheads) and GFP+/pERK- cells (F, arrows).

(G–I) pERK and GFP levels in Pomca neurons of size-matched LD (G) and HD/HF (H) pomca:EGFPras larvae treated for 30 min with saline or leptin (n = 4 for each condition), and quantification of normalized values (I).

(J) Relative pomca mRNA levels in juveniles subjected to normal feeding (n = 8) or high-fat diet (HFD; n = 7) for 10 days, 4 hr after ICV injection of recombinant leptin, determined via qRT-PCR normalized against saline-injected controls.

Scale bars represent 50 μm (D) and 10 μm (E and F). a, p < 0.05; b, p < 0.01 relative to respective LD groups (A and C). Error bars in (A)–(C), (I), and (J) show SD.

Acknowledgments

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