PMC

Effects of fasting on the body weights of a 3-, b 8-, and c 32-week-old rats. The values are shown as means ± SEM. Open circles CON groups (n = 8) and closed circles FAS groups (n = 8–9). Statistics: *p < 0.05 and ***p < 0.001 (vs. CON groups)

Effects of fasting on plasma FFA concentrations in a 3-, b 8-, and c 32-week-old rats. The values are shown as means ± SEM. Open circles CON groups (n = 8) and closed circles FAS groups (n = 8–9). Statistics: **p < 0.01 and ***p < 0.001 (vs. CON groups)

Effects of fasting on plasma insulin concentrations in a 3-, b 8-, and c 32-week-old rats. The values are shown as means ± SEM. Open circles CON groups (n = 8) and closed circles FAS groups (n = 8–9). Statistics: **p < 0.01 and ***p < 0.001 (vs. CON groups)

Effects of fasting on plasma total ketone body (I), β-hydroxybutyrate (II), and acetoacetate (III) concentrations in a 3-, b 8-, and c 32-week-old rats. The values are shown as means ± SEM. Open circles CON groups (n = 8) and closed circles FAS groups (n = 8–9). Statistics: *p < 0.05, **p < 0.01 and ***p < 0.001 (vs. CON groups)

Effects of fasting on the weights of perirenal (I) and periepididymal (II) white adipose tissues in a 3-, b 8-, and c 32-week-old rats. The values are shown as means ± SEM. Open bars CON groups (n = 8) and closed bars FAS groups (n = 8–9). Values in parentheses are relative ratios of the FAS groups to the CON groups. Statistics: *p < 0.05 and ***p < 0.001 (vs. CON groups). BW body weight

Experimental protocol. Pre-feedings were carried out for 4 days. After the pre-feedings, rats in three age groups were divided into fasting (FAS) and control (CON) groups. Beginning on the next day, the 3-, 8-, and 32-week-old rats in the FAS group were deprived of food for 2, 5, and 12 days, respectively. During the experimental periods, body weights were measured. Plasma free fatty acid (FFA), total ketone body, β-hydroxybutyrate, and insulin concentrations were assayed. On the final days of fasting, the perirenal and periepididymal white adipose tissues were isolated and weighed (downwardarrows)