Expression of transforming growth factor-beta isoforms (beta 2 and beta 3) in the mouse uterus: analysis of the periimplantation period and effects of ovarian steroids.

Expression of beta-type transforming growth factor genes (TGF beta 2 and TGF beta 3) in the mouse uterus during the periimplantation period and in response to an acute exposure to 17 beta-estradiol (E2) and progesterone (P4) was studied using Northern blot hybridization and/or immunocytochemistry. Polyclonal antipeptide antibodies specific for TGF beta 2 or TGF beta 3 were employed for immunocytochemistry. In the preimplantation uterus [days (D) 1-4 of pregnancy; day 1 = vaginal plug], immunostaining for TGF beta 2 was observed in luminal and glandular epithelia as well as in myometrium and vascular smooth muscle. In the postimplantation period (D5-D8), TGF beta 2 immunostaining was also detected in decidual cells. In contrast, TGF beta 3 immunostaining was restricted to the myometrium and vascular smooth muscle throughout the periimplantation period (D1-D8). Antisense TGF beta 2 and TGF beta 3 RNA probes were employed for Northern blotting. Northern blot hybridization revealed four TGF beta 2 transcripts (approximately 6.0, 5.0, 4.0, and 3.5 kilobases) in total uterine poly(A)+ RNA on D1-D6 and in poly(A)+ RNA from the deciduum and myometrium collected on D7 and D8 of pregnancy. These TGF beta 2 transcripts were also detected in isolated samples of deciduomata or myometrium obtained from D8 pseudopregnant mice in which the decidual cell reaction was induced experimentally on D4. The levels of these transcripts remained relatively constant during the periimplantation period. Northern blot analysis detected a 3.8-kilobase TGF beta 3 transcript in total uterine poly(A)+ RNA on D1-D6. This transcript was detected in myometrial RNA samples on D7 and D8 of pregnancy or D8 of pseudopregnancy, but was not detected in RNA from the deciduum on D7 and D8 or in that from deciduomata on D8. The effects of ovarian steroids on TGF beta 2 and TGF beta 3 mRNAs were examined in uteri of adult ovariectomized mice. Uterine TGF beta 2 or TGF beta 3 mRNA persisted in ovariectomized mice. However, an injection of E2 induced a rapid (6 h), but transient, induction (approximately 3- to 4-fold) of TGF beta 2 mRNA. An injection of P4 had no effect on TGF beta 2 mRNA levels, and coinjection of P4 with E2 did not antagonize the E2-stimulated transient accumulation of TGF beta 2 mRNA. In comparison, neither an injection of E2 nor one of P4 exerted significant effects on TGF beta 3 mRNA levels.(ABSTRACT TRUNCATED AT 400 WORDS)