Adaptive enhancement of amino acid uptake and exodus by thymic lymphocytes: influence of pH

Journal Article · Mon Nov 01 04:00:00 EST 1976 · J. Cell. Physiol.; (United States)

DOI:https://doi.org/10.1002/jcp.1040890307· OSTI ID:7238684

Peck, W A; Rockwell, L H; Lichtman, M A

Entry of certain free amino acids (alpha aminoisobutyric acid (AIB), alanine and proline), but not of leucine, into rat thymic lymphocytes increased progressively when the cells were incubated in amino acid deficient medium. Actinomycin D, cycloheximide, or a high concentration of AIB abolished the time-related increase in AIB accumulation, whereas exposure to a high concentration of leucine had no effect. This phenomenon could not be attributed to a progressive alteration in the nature of the incubation medium nor to reduced transinhibition of AIB uptake. The exodus of AIB also increased with time, but to a smaller degree than AIB entry. Initial rates of AIB entry and exodus increased with increases in the pH of the incubation medium over the range 6.5 to 8.0. The effects of pH on entry and exodus were time-related, increasing progressively over a 180-minute period. Actinomycin D, cycloheximide, and 5 mM AIB nullified the magnified time related increments in AIB transport caused by prolonged incubation at pH 8.0. These results indicate that thymic lymphocytes exhibit adaptive enhancement in the accumulation of free amino acids that are transported largely by the A or alanine-preferring system, and that the adaptive process involves both entry and exodus. Moreover, alterations in pH modify entry and exodus of these same amino acids, profoundly affect the magnitude of time-released increases, and may induce fundamental changes in the mechanism(s) serving amino acid transport.

• Research Organization: Univ. of Rochester, NY
• OSTI ID: 7238684
• Journal Information: J. Cell. Physiol.; (United States), Journal Name: J. Cell. Physiol.; (United States) Vol. 89:3; ISSN JCLLA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ACTINOMYCIN
AMINO ACIDS
ANIMAL CELLS
ANIMALS
ANTIBIOTICS
ANTIMITOTIC DRUGS
BIOCHEMISTRY
BIOLOGICAL EFFECTS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY
BODY FLUIDS
CARBOXYLIC ACIDS
CHEMISTRY
CONNECTIVE TISSUE CELLS
CYCLOHEXIMIDE
DRUGS
FUNGICIDES
LEUKOCYTES
LYMPHATIC SYSTEM
LYMPHOCYTES
MAMMALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PESTICIDES
PH VALUE
RATS
RODENTS
SOMATIC CELLS
THYMUS
UPTAKE
VERTEBRATES