Peripheral plasma concentrations of 13,14-dihydro-15-keto-prostaglandin F2 alpha and progesterone around luteolysis and during early pregnancy in the goat.

Peripheral plasma concentrations of 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM) and progesterone were determined during both luteolysis in the oestrous cycle and early pregnancy in four goats. Luteal regression, characterised by decreasing progesterone concentrations, began on day 12 or 13. PGFM concentrations showed a pulsatile pattern around this time, with peak concentrations increasing markedly as progesterone levels fell and oestrus approached. During early pregnancy progesterone concentrations did not fall after day 12 and no marked elevation of PGFM above basal values of 50-150 pg/ml was detected.