Human endometrial proteins.

Human endometrium synthesizes a number of proteins. Two of the major proteins are the low molecular weight insulin-like growth factor-binding protein (IGF-bp25) and endometrial protein PP14 (placental protein 14). Both proteins have been cloned from human decidual cDNA library and their complete amino acid sequences have been deduced. IGF-bp25 is found in various tissues and body fluids including secretory and decidualized endometrium, amniotic fluid, liver, follicular fluid and luteinized granulosa cells of preovulatory ovarian follicles. Clinical studies have shown that there is no systematic variation in the circulating levels during normal menstrual cycle, whereas in hyperstimulated cycles the levels are higher when there are many preovulatory follicles and immediately after follicle aspiration for in vitro fertilization (IVF). Some women with polycystic ovarian disease have a subnormal level of IGF-bp25 in serum. The other protein, PP14, is synthesized by secretory and decidualized endometrium, and it is also abundant in amniotic fluid. PP14 is mainly released by secretory endometrial glands during the last week of ovulatory cycles. There is a consistent variation in serum PP14 levels during normal menstrual cycle. The levels are lowest at the time of ovulation and rise steeply during the last week of luteal phase and peak at the onset of menstruation. Administration of micronized oral progesterone to normally ovulating infertile women brings about elevation in their serum PP14 levels during late luteal phase. In postmenopausal women cyclical estrogen-progestogen replacement causes elevation of serum PP14 level, but this does not take place in hysterectomized postmenopausal women.(ABSTRACT TRUNCATED AT 250 WORDS)