Metabolic cooperation in aggregates of embryonal carcinoma cells.

Metabolic cooperation may be associated with the processes of compaction and subsequent differentiation in aggregates of embryonal carcinoma cells (ECC). To determine if the gap junctions present in loose and compacted aggregates of H6 ECC are active in metabolic cooperation, aggregates of each type containing a mixture of 5-bromodeoxyuridine- and 6-thioguanine-resistant H6 cells were exposed to HAT medium, 6-thioguanine, or [3H]thymidine. These three methods indicated that some crossfeeding occurred through the small clusters of gap junctions in loose aggregates and more crossfeeding occurred through the larger clusters of gap junctions in compacted aggregates.