The PA and PAI complex formation subsequently leads to the cleavage and inactivation of both tPA and PAI-I activity. Any change in tPA and PAI-I activity in the cells or in the cell-conditioned media is therefore determined by the relative level of both of these molecules. flovent inhaler
PAI-I is a primary regulator of plasminogen activation and is synthesized in a highly regulatory manner by different cell types. In vitro studies have shown that PAI-I biosynthesis is regulated by diverse agents such as growth factors, hormones, and cytokines. PAI-I activity has been detected in rat, human, monkey, pig, and hen granulosa cells, which have been known to produce the most tPA activity in the ovary. PAI-I gene expression in the cells may be modulated in a coordinated way by different regulatory signals. Pretreatment with a low dose of FSH of granulosa cells obtained from the ovaries of diethylstilbestrol-implanted hypophysecto-mized rats induced PAI-I activity in the culture; subsequent treatment with a high concentration of FSH down-regulated the PAI-I production but induced a high level of tPA activity. These data plus the present finding indicate that the expression of tPA and PAI-I genes regulated by the gonadotropin can occur independently and coordinately.