Effect of Cell Density on Lactose Synthesis in Bovine Mammary Cell Cultures

The ability to synthesize lactose was studied in despersed cell cultures of lactating bovine mammary tissue under conditions of varying cell density, time, glucose, and lactose concentrations. The observable rate of lactose synthesis at a given time in an adequate medium is dependent on individual animal, length of time in culture, and density of cells. Rate of loss with time in the ability to synthesize lactose followed first order kinetics (half-time 11 h). Rate of synthesis per cell at a given time was an inverse function of the cell density following a linear relationship expressed by plotting the inverse of the amount accumulated versus the inverse of the cell number. A cell density for such experimental studies of about 2.5 times 10-6 cells per ml was ideal. The medium concentration of lactose and, above a minimum, that of glucose did not affect production of lactose.