Prostaglandin F2 alpha and prolactin in experimental hypogalactia in sows.

Peripheral plasma concentrations of 13,14-dihydro-15-keto-prostaglandin F2alpha(PGFM), progesterone, prolactin and oestrone were determined in 20 sows for two days before and three weeks after parturition. Groups of four sows each received one of the following five treatments post partum: 30 ml sterile 0.9 per cent saline solution intrauterinely; ovariectomy and 30 ml saline solution intrauterinely; 10 ml Lugol's iodine plus 20 ml saline solution intrauterinely; ovariectomy and 10 ml Lugol's iodine plus 20 ml saline solution intrauterinely, or progesterone (0.5 mg [kg bodyweight]-1 intramuscularly). Saline solution and iodine were administered every 48 hours, starting immediately after parturition, for one week. Ovariectomy was performed within eight hours of delivery. Progesterone was given every third day for 12 days. Piglet weight gains were used as a reflection of milk yield. In all sows, oestrone values were elevated before parturition, but fell by the end of delivery and were very low during lactation. PGFM concentrations rose during the last two days of pregnancy to reach maximal values at the time of delivery. Plasma progesterone levels declined concomitantly with the rise in PGFM values before parturition. Basal values of progesterone were achieved within 24 hours after delivery in control sows receiving saline treatment. Progesterone values fell immediately after ovariectomy in sows receiving saline or iodine treatment but were slightly elevated for one week in sows that received only intrauterine iodine treatment, suggesting that complete regression of corpora lutea is prevented by suppression of post parturient uterine prostaglandin production. Sows injected with progesterone maintained plasma values of about 5 to 15 nmol litre-1.(ABSTRACT TRUNCATED AT 250 WORDS)