[38] Methods for Assessing Estrogen Effects on New Uterine Protein Synthesis In Vitro

Estrogens stimulate the growth and maturation of the female reproductive system. Involved in this growth are increased net syntheses of RNA and protein. The sequence of these new synthetic events following estrogen interaction with a target or hormone-responsive tissue has been particularly well characterized in rat uterine tissue. Utilization of a combination of in vitro and in vivo techniques has enabled a detailed analysis of the time course of appearance and nature of these RNA and protein species. Whereas net increases in RNA and protein are not seen until 2 to 4 hours after estrogen administration, synthesis of a specific uterine protein—called induced protein (IP)—is detectable by 40 minutes, and increased IP synthesizing capacity (presumably mRNA) can be detected within 10 minutes. The methods described in this chapter are those that have been used to monitor the effects of estrogen on protein synthesis in rat uterine tissue in vitro during the first few hours of estrogen stimulation. These methods could also prove to be useful in analyzing hormonal effects on protein synthesis in other hormone-responsive tissues.