The mechanisms by which cationic amino acids influence pancreatic B-cell function have been studied by monitoring simultaneously (86)Rb(+) efflux and insulin release from perifused rat islets. The effects of two reference amino acids arginine and lysine were compared with those of closely related substances to define the structural requirements for recognition of these molecules as secretagogue...

KAAT1, a K(+)-coupled, neutral amino acid transporter from larval insect midgut, differs from other members of the Na(+):neurotransmitter transporter family (SNF) in two important ways: (1) it transports nutrient L-, alpha-amino acids, rather than neurotransmitters such as gamma-aminobutyric acid (GABA), and (2) it accepts K(+) as well as Na(+) as a co-substrate. To determine whether the restor...

In metazoans, most microRNAs imperfectly base-pair with the 3' untranslated region (3'UTR) of target mRNAs and prevent protein accumulation by either repressing translation or inducing mRNA degradation. Examples of specific mRNAs undergoing microRNA-mediated repression are numerous, but whether the repression is a reversible process remains largely unknown. Here we show that cationic amino acid...

L-Glutamic acid is a major excitatory neurotransmitter in the mammalian central nervous system. The termination of the glutamatergic transmission and the clearance of the excessive, neurotoxic concentrations of glutamate is ensured by a high affinity glutamate uptake system. Four homologous types of Na/K-dependent high affinity glutamate transporters, glutamate/aspartate transporter, glutamate ...

OBJECTIVE To identify possible mechanisms linking obesity in pregnancy to increased fetal adiposity and growth, a unique mouse model of maternal obesity associated with fetal overgrowth was developed, and the hypothesis that maternal obesity causes up-regulation of placental nutrient transporter expression and activity was tested. METHODS C57BL/6J female mice were fed a control (C) or a high-...

In metazoa, microRNAs (miRNAs) imperfectly base-pair with the 3'-untranslated region (3'UTR) of mRNAs and prevent protein accumulation by either repressing translation or inducing mRNA degradation. Examples of specific mRNAs undergoing miRNA-mediated repression are numerous, but whether the repression is a reversible process remains largely unknown. Here, we show that cationic amino acid transp...