Total, latent and active collagenase during the course of post-partum involution of the rat uterus. Effect of oestradiol

Abstract

1. Total, active and latent collagenase activities were determined by direct assay of tissue homogenates. 2. The rate of collagen breakdown during post-partum involution of the rat uterus is correlated with the total activity of collagenase. Both are low at parturition, reach a maximum within 24h and fall slowly to low values of 5 days post partum. This temporal correlation strongly supports the hypothesis that collagenase participates in collagen breakdown in vivo. 3. Further support for this hypothesis is provided by the finding that oestradiol-17 beta (100 micrograms/day, intraperitoneally injected), which inhibits the breakdown of collagen by 36% during the first 4 days of involution, produces a closely corresponding decrease in total collagenase activity. 3. The effect of oestradiol in lowering collagenase activity is not due to alterations in collagen substrate, collagenase kinetic behaviour or latent-to-active enzyme conversion. 4. Of the total assayable collagenase, about 35% is fully active and 65% is in a latent form. 5. About 70% of this latent form can be activated by a serine proteinase found, together with collagenase, in the insoluble fraction of uterine homogenates.

Removal of collagen bundles in murine uterus during postpartum involution

“…This result agrees with biochemical studies (Jeffrey et al, 1971;Halme and Woessner, 1975). On the day of parturition, there is little collagenase, the majority being procollagenase that is not yet activated (Woessner, 1979;Roswit et al, 1983). The principal cellular origin of procollagenase is obscure.…”

The effects of the aromatase inhibitor fadrozole hydrochloride on fetuses and uteri in late pregnant rats

“…Ryan & Woessner (1972) showed that administration of E 2 to parturient rats strongly inhibits the loss of collagen from the involuting uterus, and found that this effect is due to inhibition of collagen degradation rather than stimulation of collagen synthesis. Furthermore, Woessner (1979) found that injection with E 2 causes a decrease in uterine collagenase activity that is correlated with the rate of collagen breakdown. Frankel et al (1988) found that E 2 induces alpha 2 (I) and alpha 1 (III) collagen mRNAs in the immature rat uterus, and Dyer et al (1980) reported that E 2 stimulates both synthesis and degradation of collagen in the ovariectomized rat uterus.…”

Collagen Degradation and Mucosal Mast Cell in Endometrium of Mouse Uterus during Early Postpartum Period

“…Thus, the postpartum collagen degradation might occur in the edematous area at PM. However, the majority of eollagenase is latent at PM [Woessner, 1979;Rosvvit et al. 19831.…”

“…19831. Telopeptidase, which can cleave the C-terminal cross-linkage for stabilizing collagen fibers, exists in the postpartum uterus [Nakano and Scott, 1987], In contrast to eollagenase which does not reach a maximal activity until postpartum day 1 [Woessner. 1979], telopeptidase activity shows a maximum immediately after parturition [Nakano and Scott.…”