Serum-dependent regulation of alpha-aminoisobutyric acid uptake in bovine granulosa cells.

The removal of serum from the medium of ovarian granulosa cells in exponential or confluent stages of growth results in a rapid and pronounced decrease in the rate of transport of the non-metabolizable amino acid, alpha-aminoisobutyric acid. This decrease is rapidly and completely reversed by the addition of serum. The decrease and its reversal are insensitive to inhibitors of RNA and protein syntheisis and are unaffected by a number of other metabolic inhibitors. The serum requirement cannot be replaced by peptide hormones known to stimulate cell division and secretion by these cells. These data are consistent with a model of post-translational control of AIB transport by a high-molecular-weight component of serum.