Effect of treatment with retinyl palmitate, progesterone, oestradiol and tamoxifen on secretion of a protein similar to retinol-binding protein during uterine gland development in neonatal pigs

Abstract

Previous work has demonstrated that uterine secretion of a protein with M(r) 20,000 and pI 5.5 increases during neonatal endometrial gland development. Uterine tissue was collected from a 60-day-old gilt and cultured in 0.1 x leucine minimum essential medium (MEM) plus 50 muCi [3H]leucine to determine whether this protein is related to retinol-binding protein (RBP). Conditioned medium was immunoprecipitated using anti-human RBP antiserum. A radioactive protein with M(r) 20,000 and pI 5.5 was specifically immunoprecipitated from the conditioned medium. Uteri from neonatal gilts were collected at birth (day 0) and on days 3, 6, 9 and 12, cultured, and secreted proteins were immunoprecipitated as described above to determine whether secretion of immunoreactive RBP increased coincident with initiation of endometrial gland development. Immunoprecipitation demonstrated that the secretion of immunoreactive RBP increased by day 3. Finally, gilts were treated each day with corn oil, retinyl palmitate (10,000 iu day-1), progesterone (20 mg day-1), oestradiol (100 micrograms day-1) or tamoxifen (1 mg day-1 or 0.1 mg day-1) for 14 days beginning at birth to determine the effects of these treatments on endometrial gland development and uterine secretion of immunoreactive RBP. On day 14, gilts were killed and uteri collected. Uterine tissue samples were prepared for histology (to evaluate uterine development using morphometry) and for culture in 0.1 x methionine MEM plus 25 muCi [35S]methionine (to evaluate uterine protein synthesis).(ABSTRACT TRUNCATED AT 250 WORDS)