Progesterone-induced lysis of rat kidney lysosomes as studied by changes in light-absorbance.

1. A rat kidney lysosomal fraction was prepared by the method of Maunsbach (1966) and characterized by its content of representative marker enzymes for lysosomes, mitochondria, peroxisomes and endoplasmic reticulum. 2. It was shown that both pH-dependent and progesterone-induced lysis lead to a decrease in the E(520) of suspensions of this preparation. This decrease parallels quantitatively and temporally the release of soluble acid phosphatase. 3. It is suggested that E(520) measurements are a valid method for the continuous measurement of changes in lysosomal integrity. 4. As an example, results are included which demonstrate the ability of Zn(2+) to stabilize lysosomes against spontaneous and progesterone-induced lysis.