Regulation of amino acid transport in isolated rat hepatocytes during development

✍ Scribed by S. Leoni; S. Spagnuolo; L. Dini; L. Conti Devirgiliis

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 776 KB
• Volume: 130
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/jcp.1041300115

✦ Synopsis

The effect of amino acid depletion or supplementation and the effect of glucagon and insulin on the amino acid transport mediated by s stem A were acid (AIB) or N-methyl 2-amino [l-'4C]isobutyric acid (MeAIB) in rat hepatocytes, freshly isolated at different stages of pre-and postnatal development. The data obtained show that the Na+-dependent uptake was higher at the earliest developmental stages, and steadily decreased until the adult level. The hormones increased AIB and MeAlB uptake enhancing the V, , , , while the K, was unchanged. This effect was evident in cells from adult and 18-20day-old fetuses, while no response was present before the 18th day of fetal life and in the perinatal period. Actinomycin D or cycloheximide abolished this hormone-dependent increase. A decrease in AIB and MeAlB transport after incubation in an amino acid-rich medium was demonstrated at all ages tested, but was particularly evident in the prenatal life. The increase in the activity of the system following amino acid starvation was shown to be mostly deDendent from de novo Drotein svnthesis in the fetal life: on the contrarv in investigated by determining the uptake of either 2-amino [I-7 .

4C]~sobutyric

t h e adult the increase a'ppeared 'to transinhibition of the transport.