The variations of estrogen receptor, progesterone receptor, cAMP, ODC activity and RNA synthesis of deciduomata in pseudopregnant rats.

The present study was done to define the conditions of implantation of fertilized ovum from serial day-to-day changes in the tissue weight of deciduomata in pseudopregnancy, estrogen receptor (ER), progesterone receptor (PR), cAMP content, RNA synthesizing capacity and ornithine decarboxylase activity (ODC). Pseudopregnancy was induced in Wistar rats in the estrus morning by vaginocervical stimulation. At the 4th day of pseudopregnancy deciduomata was induced by intraluminal instillation of olive oil with simultaneous oophorectomy and intramuscular injection of 20 mg progesterone depot (the day of induction of decidualization was arbitrarily expressed as D0 and the ensuing days, as D1, D2 and so on). The number of binding sites of ER and PR was estimated by exchange assay using dextran charcoal. cAMP content and RNA synthesizing capacity were determined by RIA and 3H-UTP uptake, respectively. ODC activity was measured by the method of Jänne and Williams-Ashman. Following the induction of deciduomata the uterus weight (unilateral) increased abruptly to 2-fold at D2 and approximately 30-fold (4.5 g) at D8 and declined thereafter. ER diminished in a linear fashion from 2.77 x 10(-10) M at D2 to 0.53 x 10(-10) M at D7. On the other hand, PR was estimated 2.9 x 10(-10) at D2. 2.5 x 10(-10) M at D5 and decreased further at D6 and D7, cAMP was 77 nmoles/mg protein at D2 and decreased rapidly from D3 onward. RNA synthesizing capacity declined in a linear fashion from D3 to 1/2 to D5 and 1/3 at D7. ODC was found 1.7 CO2 nmoles/mg protein at D2, decreased at D3 and D4, but remained nearly the same at D4 and D5.