Impact of combined hormonal pretreatment (insulin+TSH) on the imprinting of hormones administered in combination to Chinese hamster ovary cell culture.

Cultured Chinese hamster ovary (CHO) cells were treated (imprinted) with insulin and with thyrotropin (TSH) related to gonadotropins (FSH+LH). When one week later the treatment was repeated with one of the hormones, considerable differences could be observed in the binding capacity of the cells. In the hormone combination TSH was able to evoke persistent imprinting only to a markedly lesser degree than insulin, meanwhile the imprintatory effect of insulin was of greater extent even on the cell regarded to be unspecific for insulin. Hormone treatment of one hour duration--when investigated immediately after--did not extinct the binding capacity to TSH but enhanced that to insulin. With the deterioration of the conditions of culturing, the enhanced binding capacity disappeared.