Characteristics of the JA-2 generations by <i>kibei</i> status.

<p>BMI, body mass index; BP, blood pressure; 2-h, two-hour post-load; HOMA-IR,</p><p>homeostasis model assessment-insulin resistance; HDL, high-density lipoprotein.</p><p>Values are expressed as numbers, means ± SD, medians (25th–75th percentile levels), or percentages.</p><p>The parameters were analyzed after adjusting for age and sex.</p><p>^a<i>P</i> < 0.05 between <i>kibei</i> and non-<i>kibei</i>.</p><p>Characteristics of the JA-2 generations by <i>kibei</i> status.</p

Characteristics of study subjects.

<p>JA-1, first-generation Japanese-Americans; JA-2, second- or later-generation Japanese-Americans; BMI, body mass index; BP, blood pressure; 2-h, two-hour post-load; HOMA-IR, homeostasis model assessment-insulin resistance; HDL, high-density lipoprotein.</p><p>Values are expressed as numbers, means ± SD, medians (25th–75th percentile levels), or percentages.</p><p>The parameters were analyzed after adjusting for age and sex.</p><p>^a<i>P</i> < 0.05 between Japanese and JA-1.</p><p>^b<i>P</i> < 0.05 between Japanese and JA-2.</p><p>^c<i>P</i> < 0.05 between JA-1 and JA-2.</p><p>Characteristics of study subjects.</p

Distinct Time Course of the Decrease in Hepatic AMP-Activated Protein Kinase and Akt Phosphorylation in Mice Fed a High Fat Diet

<div><p>AMP-activated protein kinase (AMPK) plays an important role in insulin resistance, which is characterized by the impairment of the insulin-Akt signaling pathway. However, the time course of the decrease in AMPK and Akt phosphorylation in the liver during the development of obesity and insulin resistance caused by feeding a high fat diet (HFD) remains controversial. Moreover, it is unclear whether the impairment of AMPK and Akt signaling pathways is reversible when changing from a HFD to a standard diet (SD). Male ddY mice were fed the SD or HFD for 3 to 28 days, or fed the HFD for 14 days, followed by the SD for 14 days. We examined the time course of the expression and phosphorylation levels of AMPK and Akt in the liver by immunoblotting. After 3 days of feeding on the HFD, mice gained body weight, resulting in an increased oil red O staining, indicative of hepatic lipid accumulation, and significantly decreased AMPK phosphorylation, in comparison with mice fed the SD. After 14 days on the HFD, systemic insulin resistance occurred and Akt phosphorylation significantly decreased. Subsequently, a change from the HFD to SD for 3 days, after 14 days on the HFD, ameliorated the impairment of AMPK and Akt phosphorylation and systemic insulin resistance. Our findings indicate that AMPK phosphorylation decreases early upon feeding a HFD and emphasizes the importance of prompt lifestyle modification for decreasing the risk of developing diabetes.</p></div

Hepatic AMPK and Akt phosphorylation levels in mice subjected to dietary change or SD.

<p>(A and B) Representative western blot quantification of AMPK phosphorylation (relative to total AMPK protein). n = 4‒5 per group. (C and D) Representative western blot quantification of insulin-stimulated Akt phosphorylation (relative to total Akt protein). n = 4‒5 per group.</p

Dietary change improves weight gain, liver steatosis, glucose tolerance, and insulin resistance.

<p>The diet was changed on day 14 (black diamonds) or continued as a SD (white circles). (A) Body weight. Results are means ± standard deviation. n = 5 per group. *<i>P</i> < 0.05. (B) Oil Red O-stained liver sections from SD-fed mice or those subjected to a dietary change. Scale bar, 100 μm. (C and D) Intraperitoneal glucose tolerance test (GTT) in SD-fed mice or those subjected to a dietary change on day 3 (C) or day 14 (D). (E and F) Insulin tolerance test (ITT) in SD-fed mice or those subjected to a dietary change on day 3 (E) or day 14 (F). Results are means ± standard deviation. n = 4‒5 per group. *<i>P</i> < 0.05.</p

Hepatic AMPK and Akt phosphorylation levels in SD- or HFD-fed mice.

<p>(A and B). Representative western blots and quantification of AMPK phosphorylation (relative to total AMPK protein). n = 4 per group. *<i>P</i> < 0.05. (C) and (D). Representative western blots and quantification of insulin-stimulated Akt phosphorylation (relative to total Akt protein). n = 4 per group. *<i>P</i> < 0.05.</p