Abstract
Pregnancy influences the functional properties of both genital and extragenital connective tissues. The sex hormones induce a major part of these changes but also corticosteroids may play a role, as their concentration is elevated during pregnancy and early post-partum. The biomechanical properties of the pubic symphysis, muscle tendon and skin of intact and adrenalectomized rats during the first ten days of the post-partum phase were investigated. For the pubic symphysis and the muscle tendon of the intact animals there was a decrease of the stiffness in the early post-partum phase followed by a restoration. For the adrenalectomized animals there was no such initial decrease, which indicates that relaxation during pregnancy had been less pronounced. However, the strength of muscle tendons from the adrenalectomized animals was markedly decreased during the post-partum phase. The stiffness of the skin from the intact animals was increased in the early post-partum period. This increase was also found in adrenalectomized animals, but here the strength and stiffness were not only restored to the intact level but became further reduced during the post-partum period. It seems therefore that the adrenal glands not only participate in the development of adaptive changes during pregnancy, but also play a role in the stabilization of extragenital connective tissues in the post-partum phase.