The Mechanism of Symphyseal Relaxation. The Distribution of Reducing Groups, Hexoseamine, and Proteins in Symphyses of Normal and Relaxed Guinea Pigs1

ALTHOUGH the presence of relaxin has been found to be a normal accompaniment of pregnancy in a number of species other than the guinea pig, only in the latter has a function definitely been assigned to this hormone. In an attempt to broaden our knowledge of possible areas of hormone-tissue interaction, a study has been made of the chemical changes occurring in the connective tissue of the guinea pig pubic symphysis during relaxation. Comparative histological studies of the effects of estrogen, progesterone, relaxin, and combinations of these hormones have been made by Talmage (1947), who noted a reversible dissolution of cartilage and “breakdown” of connective tissue fibers in the pubic symphyses of guinea pigs treated first with estrogen and then with relaxin. He also observed a very considerable increase in alkaline phosphatase in symphyseal tissue following prolonged treatment with estrogen; the accumulation and distribution of phosphatase did not appear to be changed markedly upon relaxation.