Embryonic Cadaverine Signaling: Implications for Plasma Free Amino Acid and Skeletal Muscle Energy Metabolism in Newly Hatched Chicks.

Cadaverine is a bioactive substance derived from lysine degradation by lysine decarboxylase and has gained attention for its physiological effects. Studies in rodents have revealed its role as a cell growth regulator, particularly intestinal bacterial-produced cadaverine. However, the nutritional and physiological roles of cadaverine during the embryonic period remain unclear, especially considering the immature state of the gut microbiota and digestive functions during this stage. This study explored the potential functions of cadaverine as a nutritional and metabolic signal during chicken embryonic development. Experiments were conducted using an in ovo administration method to evaluate the effects of nutritional bioactive substances on developing chicken embryos. Although there were no observable changes in body or organ weights of newly hatched chicks following in ovo cadaverine administration to day 18 chick embryos, plasma tryptophan, Nτ-methylhistidine, and Nπ-methylhistidine concentrations decreased and the gene expression of insulin/insulin-like growth factor 1 signaling in skeletal muscle was upregulated. These findings imply that cadaverine influences tryptophan metabolism and skeletal muscle catabolism during the embryonic period, suggesting its role as a bioactive factor contributing to energy metabolism signaling in skeletal muscle.

Pharmacokinetics and tissue distribution of orally administrated imidazole dipeptides in carnosine synthase gene knockout mice.

Imidazole dipeptides (ID) are abundant in skeletal muscle and the brain and have various functions, such as antioxidant, pH-buffering, metal-ion chelation. However, the physiological significance of ID has not been fully elucidated. In this study, we orally administered ID to conventional carnosine synthase gene-deficient mice (Carns-KO mice) to investigate the pharmacokinetics. Carnosine or anserine was administered at a dose of 500 mg (∼2 mmol) per kilogram of mouse body weight, and ID contents in the tissues were measured. No ID were detected in untreated Carns-KO mice. In the ID treatment groups, the ID concentrations in the tissues increased in a time-dependent manner in the gastrocnemius muscle, soleus muscle, and cerebrum after ID administration. Our findings suggest that the Carns-KO mice are a valuable animal model for directly evaluating the effects of dietary ID and for elucidating the physiological functions of oral ID administration.

Phytosterols in onion contribute to a sensation of lingering of aroma, a koku attribute.

We aimed to examine the substance in a precipitate of heat-treated onion concentrate (HOC) that contributes to a sensation of lingering of aroma, a koku attribute induced by the sensing of richness and persistence in terms of taste, aroma and texture. Adding precipitate, separated from HOC, to consommé enhanced the lingering sensation of aroma in the consommé more than adding the supernatant from HOC. After the precipitate was washed with hot water and ethanol its enhancing effect disappeared. Analysis of the HOC precipitate showed that it contained phytosterols, such as beta-sitosterol and stigmasterol. Tests of binding to aroma compounds showed that both sterols, as well as the washed precipitate, were able to bind methyl propyl disulfide and N-hexanal. Thus phytosterols in the HOC precipitate seemed to bind and hold the aroma compounds and gradually release them, inducing a lingering sensation of aroma under the koku concept during consumption.