AJP - Endocrinology and Metabolism, Vol 239, Issue 3 201-E207, Copyright © 1980 by American Physiological Society
Regulation of chondrosarcoma metabolism by cyclic adenosine 3'5'-monophosphate
W. D. McCumbee and H. E. Lebovitz
The in vitro effects of cyclic AMP on amino acid transport and synthesis of
macromolecules in the Swarm rat chondrosarcoma were investigated using the
cyclic AMP analogue, N6-monobutyryl cyclic AMP (MBcAMP), and the
phosphodiesterase inhibitor, 3-isobutyl-1-methylxanthine (MIX). Amino acid
transport was assessed by measuring alpha-amino-[1-14C]isobutyrate (AIB)
uptake. The synthesis of macromolecules was estimated by measuring
radiolabeled precursor incorporation into total proteins, proteoglycan, and
RNA. MBcAMP stimulated [14C]AIB uptake, [3H]uridine transport, and UTP
formation. MBcAMP inhibited 35SO4 and [3H]leucine incorporation into
proteoglycan and stimulated [3H]uridine incorporation into RNA. MIX
elevated endogenous cyclic AMP levels in the Swarm rat chondrosarcoma and
mimicked the effects of MBcAMP on AIB transport and radiolabeled precursor
incorporation into macromolecules. For comparative purposes, the effects of
MBcAMP on AIB uptake and macromolecule synthesis in rat costal cartilage
segments were investigated. MBcAMP and MIX stimulated AIB uptake by costal
cartilage segments, inhibited [3H]leucine incorporation into total protein
and 35SO4 incorporation into proteoglycan, and had no effect on [3H]uridine
incorporation into RNA.
