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Working muscle conserves adenosine triphosphate (ATP) for muscle contraction by attenuating protein synthesis through several different pathways. Regulated in development and DNA damage response 1 (REDD1) is one candidate protein that can itself attenuate muscle protein synthesis during muscle contraction. In this study, we investigated whether endurance exercise induces REDD1 expression in association with decreased mammalian target of rapamycin (mTOR) complex I (mTORC1) signaling and global protein synthesis in rat skeletal muscle. After overnight fasting, rats ran on a treadmill at a speed of 28 m/min for 60 min, and were killed before and immediately, 1, 3, 6, 12, and 24 h after exercise. REDD1 mRNA and corresponding protein levels increased rapidly immediately after exercise, and gradually decreased back to the basal level over a period of 6 h in the gastrocnemius muscle. Phosphorylation of mTOR Ser2448 and S6K1 Thr389 increased with the exercise, but diminished in 1–3 h into the recovery period after cessation of exercise. The rate of protein synthesis, as determined by the surface sensing of translation (SUnSET) method, was not altered by exercise in fasted muscle. These results suggest that REDD1 attenuates exercise‐induced mTORC1 signaling. This may be one mechanism responsible for blunting muscle protein synthesis during exercise and in the early postexercise recovery period.

Our results suggest that sodium alginate oligosaccharides attenuate salt-induced hypertension in Dahl S rats not through reducing salt absorption, but probably through a direct action on vascular vessels.

Long-term consumption of Miso soup attenuated blood pressure elevation in Dahl salt-sensitive rats with salt-induced hypertension. The blood pressure reduction was due to, at least in part, constituent(s) of the Miso that increase natriuresis and diuresis and enhance dopaminergic nervous activity in the kidney.

Androgen receptor (AR) is known to bind to the same cis-element that glucocorticoid receptor (GR) binds to. However, the effects of androgen signaling on glucocorticoid signaling have not yet been elucidated. Here, we investigated the effects of testosterone on dexamethasone (DEX, a synthetic glucocorticoid)-induced apoptosis of pancreatic β-cells, which might be involved in the pathogenesis of type 2 diabetes mellitus in males. We used INS-1 #6 cells, which were isolated from the INS-1 pancreatic β-cell line and which express high levels of AR. Testosterone and dihydrotestosterone inhibited apoptosis induced by DEX in INS-1 #6 cells. AR knockdown and the AR antagonist hydroxyflutamide each diminished the anti-apoptotic effects of testosterone. AR was localized in the nucleus of both INS-1 #6 cells and pancreatic β-cells of male rats. Induction of thioredoxin-interacting protein (TXNIP) is known to cause pro-apoptotic effects in β-cells. Testosterone suppressed the DEX-induced increase of TXNIP at the transcriptional level. A Chromatin immunoprecipitation assays showed that both AR and GR competitively bound to the TXNIP promoter in ligand-dependent manners. Recombinant DNA-binding domain of AR bound to the same cis-element of the TXNIP promoter that GR binds to. Our results show that AR and GR competitively bind to the same cis-element of TXNIP promoter as a silencer and enhancer, respectively. These results indicate that androgen signaling functionally competes with glucocorticoid signaling in pancreatic β-cell apoptosis.

The intestinal expression of the CYP3A subfamily was investigated in female rats, and the intestinal metabolism of two CYP3A substrates, testosterone and rifabutin, was examined and compared between males and females. CYP3A1/23 and CYP3A2 intestinal expression was barely detected in male and female rats. Although CYP3A9 was predominantly expressed in the female rat liver, its expression in the intestine was not different between the two sexes. The rate of testosterone 6b b-hydroxylation in the female intestine was similar to that for males. Rifabutin was also metabolized at similar rates in both intestines, although the metabolic rate was greater in the female liver. These results indicate that the intestinal drug metabolizing activity of the CYP3A subfamily is similar between males and females, and that CYP3A9 is involved in the intestinal metabolism of CYP3A substrates in both sexes.