[Sex hormones in young pigs. I. Concentrations of plasma progesterone and estrogens of sows and urinary estrogens after synchronization of estrus and ovulation].

Treatment for synchronised heat and ovulation, using Suisynchron-Prämix, Bernburg, pregnant-mare serum gonadotrophin (PMSG), and human chorionic gonadotrophin (HCG), was followed with twelve gilts by daily measurement over 31 days of urine oestrogens, plasma progesterone as well as of plasma oestrogens during the oestric phases. Hormonal developments recorded during the oestrus and luteum phases were in agreement with the concepts and data so far known for the subject. An intermediate peak of oestrogen concentration was clearly recordable in the di-oestrus, that is between the tenth and 15th days of cycle. Its physiological importance will have to be further investigated.