The progesterone receptor (PR) has three isoforms, PR-A, PR-B, and PR-C, which have different physiological effects. PR-A may inhibit PR-B-mediated transcription. Parturition requires withdrawal of progesterone (P4). This could occur through decreased P4 concentrations and/or a change in PR isoforms to diminish the effect of P4. We measured mRNA for PR isoforms in rat uterine tissues through la...

The clinical and pathological manifestations of a disease occurring in the late stages of pregnancy or following parturition in the guinea pig are described. The similarity of this disease to toxemia of pregnancy in the rabbit is discussed. The disease appears to be of endogenous origin and is in some way associated with a disordered metabolism occurring at about the time of parturition.