Observation of a Spreading Factor Present in Mammary Gland Extracts.

Abstract

Extracts of mammary glands taken from female albino rats, pregnant 3-18 days, indicated the presence of a spreading factor when assayed by the spreading type method. The concn. of the factor increased until about the 12th day, followed by a gradual decline. Mammary gland extracts from normal males, normal females and castrate animals failed to exhibit a spreading factor. Turbidimetric assays indicated that the spreading factor did not hydrolyze the substrate, hyaluronidate. Lability tests showed that it is not inactivated until heated to 70[degree]C for 10 min., indicating that it is not hyaluronidase.