Growth-dependent AIB and meAIB uptake in LLC-PK/sub 1/ cells: effects of differentiation inducers and of TPA

Journal Article · Sat Jan 01 04:00:00 EST 1983 · J. Cell. Physiol.; (United States)

DOI:https://doi.org/10.1002/jcp.1041140207· OSTI ID:5910434

Amsler, K; Shaffer, C; Cook, J S

Cultured pig kidney cells designated LLC-PK/sub 1/, previously shown to acquire Na/sup +/-dependent concentrative transport of hexoses as the cells become growth arrested, also show Na/sup +/-dependent concentrative uptake of the amino acid analogs /sup 2/-aminoisobutyric acid (AIB) and (methyl) meAIB. This A system-like transport is most active in sparse, growing cultures and becomes stepped down at confluence. The cell/medium equilibrium distribution ratio of the lipophilic cation tetraphenylphosphonium ion (TPP/sup +/) decreases in parallel fashion, suggesting that a decrease in membrane potential may be a major factor in the stepdown. Differentiation inducers (hexamethylene bisacetamide) and phosphodiesterase inhibitors (theophylline, methylisobutyl xanthine) accelerate the stepdown, but even in the presence of these compounds addition of the tumor promoter 12-0-tetradecanoylphorbol-13-acetate (TPA) results in the maintenance of a high level of AIB and meAIB uptake. In all these respects the changes in A system like amino acid transport are the reciprocal of those seen for concentrative hexose transport, although the driving force appears to be the same for both systems. The TPA analogs phorbol and 4-0-methyl TPA which are inactive in tumor promotion are inactive in this system as well. In confluent, already stepped-down cultures, addition of TPA leads to a rapid (2-6 hour) stimulation of AIB and meAIB uptake. The enhancement is sensitive to cycloheximide and actinomycin D. 30 references, 6 figures.

• Research Organization: Oak Ridge National Lab., TN
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 5910434
• Journal Information: J. Cell. Physiol.; (United States), Journal Name: J. Cell. Physiol.; (United States) Vol. 114; ISSN JCLLA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
59 BASIC BIOLOGICAL SCIENCES
ALANINES
ALKALI METAL COMPOUNDS
AMINO ACIDS
ANIMALS
BIOLOGICAL EFFECTS
BODY
CARBOXYLIC ACIDS
CARCINOGENS
CATIONS
CELL CULTURES
CELL DIFFERENTIATION
CHARGED PARTICLES
DATA
DOMESTIC ANIMALS
ENZYME INHIBITORS
ESTERS
EXPERIMENTAL DATA
INFORMATION
IONS
KIDNEYS
MAMMALS
MEMBRANE TRANSPORT
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PHORBOL ESTERS
SODIUM COMPOUNDS
SWINE
UPTAKE
VERTEBRATES