Effect of a 9‐week exercise training regimen on expression of developmental genes related to growth‐dependent fat expansion in juvenile rats

• Published in: Physiological reports 2018-09, Vol.6 (19), p.e13880-n/a
• Main Authors: Kato, Hisashi, Shibahara, Takuya, Rahman, Nazibur, Takakura, Hisashi, Ohira, Yoshinobu, Izawa, Tetsuya
• Format: Article
• Language: English
• Subjects: Adipocytes; Adipogenic gene; Adiponectin; Adipose tissue; Adipose Tissue and Obesity; Age; Development and Regeneration; developmental gene; Diabetes; Endurance and Performance; exercise training; Fitness equipment; Fitness training programs; Gene expression; Homeobox; Hox gene; Leptin; lipolytic gene; Original Research; Peroxisome proliferator-activated receptors; Physiology; Proteins; Regulatory Pathways; Running; white adipose tissue
• ISSN: 2051-817X
• DOI: 10.14814/phy2.13880

This study examined the association between changes in mRNA expression of development‐related genes including those of the homeobox (Hox) family and growth‐dependent increases in inguinal, mesenteric, and epididymal white adipose tissue (WAT) at 4, 6, 10, and 14 weeks of age in rats. We also examined the effects of a 9‐week exercise training regimen starting at 5 weeks of age on the mRNA levels of the genes of interest. HoxC8, HoxC9, Gpc4, Bmpr1a, Pparγ, Pgc1α, Adrb3, Hsl, leptin, and adiponectin in each type of WAT – except HoxA5, Gpc4, and Pgc1α in epididymal – showed a positive association between WAT weights and WAT mRNA levels; however, the slope of the regression lines exhibited fat depot‐specific differences. HoxA5 showed no significant association, and Gpc4 and Pgc1α showed a negative association in epididymal WAT. After exercise training, the mean HoxA5, HoxC8, HoxC9, HoxC10, Gpc4, Pparγ, and Pgc1α mRNA levels in inguinal WAT were outliers on the regression line between mean mRNA level and WAT weight in control rats – that is, mean HoxA5 and Pgc1α mRNA level was higher, whereas HoxC8, HoxC9, HoxC10, Gpc4, and Ppar levels were lower in exercise‐trained rats than in same‐age controls. Pparγγ and adiponectin levels were upregulated in epididymal WAT, while HoxA5 was downregulated, but HoxC9, Gpc4, Pparγ, and adiponectin levels were upregulated in mesenteric WAT. These results suggest that some of the developmental genes tested may have fat depot‐specific roles in the growth‐dependent expansion of WAT, and that Hox genes that are activated in response to exercise training also vary among different WAT types. This study examined the association between changes in mRNA expression of development‐related genes and growth‐dependent increases in inguinal, mesenteric, and epididymal white adipose tissue (WAT) at early postnatal stages in rats. We also examined whether these mRNA expressions were affected by exercise training. Some of the developmental genes tested may have fat depot‐specific roles in the growth‐dependent expansion of WAT, and that Hox genes that are activated in response to exercise training also vary among different WAT types.