Prolactin-enhanced uteroglobin synthesis and secretion by uteri of estrogen and progesterone treated juvenile rabbits

Juvenile (22 day old) and neonatal (nine day old) female rabbits were exposed to a nine day injection protocol. Each day, the animals were either sham (carrier only) injected or received a subcutaneous injection of estradiol (either 10 or 100 micrograms/kg/24hr^-1) for the first two days, ovine prolactin (14 I.U./kg/24hr^-1) for the following three days and progesterone (3 mg/kg/24hr^-1) for the remaining four days of the nine day injection period. Eleven treatment groups existed for each age group. Juvenile animals, which received the 100 micrograms estradiol/kg/24hr^-1, sham, progesterone protocol or the 100 microgram estradiol/kg/24hr^-1, ovine prolactin, progesterone protocol, produced detectable amounts of uteroglobin (UG) in their uterine secretions (0.034 ± 0.030 mg UG and 0.098 ± 0.023 mg UG/mg total protein, respectively). Verification of de novo uterine UG synthesis was verified by ³⁵S-methionine incorporation, in vitro, into UG, at a significant level relative to total protein incorporation of radiolabel.