Figure 4

The level of α-MSH regulates somatic growth and sexual size dimorphism in pomca mutant adults. (A,B) Lateral view of F2 homozygous male (A) and female (B) mutants compared with WT controls at 12 mpf. Scale bars = 1 cm. (C) BW curves of zebrafish from the juvenile to adult stages in the three experimental male groups (WT, α-MSH^−7aa, and α-MSH^−8aa; n = 20/group). (D) Bar graph showing the BWs in the three experimental male groups (n = 20/group) under normal feeding conditions at 4 and 10 mpf stages. (E) Whole mounts of viscera and visceral fat pads in the α-MSH^−7aa and α-MSH^−8aa fish groups at 12 mpf, showing increased fat pad size in the α-MSH. (F,G) Histological features of adipose tissue in hematoxylin and eosin (HE)-stained sagittal sections, showing (F) male and (G) female specimens. Left: HE-stained sagittal sections, showing visceral and subcutaneous adipose tissue contents in the three experimental male groups (n = 5/group). Right: Bar graph showing the body fat volume ratios calculated by morphometric analysis of fat on visceral and subcutaneous adipose tissue average size in each experimental group (n = 5 in each group). Values are the mean ± SEM. * p < 0.05, ** p < 0.01, and *** p < 0.001 compared with WT control groups.