Plasma concentrations of progesterone and 13,14\x=req-\ dihydro-15-keto-prostaglandin F-2\g=a\during regression of the corpora lutea of lactation in the bandicoot(Isoodon macrourus)

Summary. Plasma progesterone concentrations (mean \m=+-\s.e.m.) declined from 7\m=.\5\m=+-\ 1\m=.\2ng/ml and 7\m=.\5\m=+-\1\m=.\0 ng/ml to < 1 ng/ml after removal of pouch young (RPY) from bandicoots at Days 24 and 30 of lactation respectively. In all 7 bandicoots, the corpora lutea of lactation showed signs of regression and, in 5 of these bandicoots, a premature ovulation had occurred 6\p=n-\9days after RPY. There was no change in the concentration of PGFM after RPY, and uterine prostaglandin F-2\g=a\may not be involved in luteal regression in the bandicoot