Lysosomal enzyme changes in growing and regressing mammary tumours.
Rat mammary tumours induced by 7,12-dimethylbenz[a]anthracene can undergo repeated growth and regression during successive pregnancies. In a 10-day period after birth about half of the tumours regressed 50% or more. The concentrations of the lysosomal enzymes increased in regressing mammary tumours to the following multiples of the initial values: beta-glucuronidase, 7.7; beta-galactosidase, 3.9; cathepsin, 2.9; acid ribonuclease, 2.1; arylsulphatase A, 1.5; acid phosphatase, 1.4. In contrast, several non-lysosomal enzymes failed to increase. Activities in the post-partum uterus increased to the following multiples of the initial values: beta-glucuronidase, 5.8; cathepsin, 5.5; acid ribonuclease, 4.3; beta-galactosidase, 2.2; acid phosphatase, 1.8. Arylsulphatase A in the post-partum uterus decreased significantly, suggesting a non-lysosomal distribution or a special function related to pregnancy. No other significant changes were observed in the lysosomal or non-lysosomal enzymes in the hormone-independent liver or hormone-dependent normal mammary gland. The ratio of free to bound arylsulphatase A and acid ribonuclease decreased slightly 1-3 days after birth because of problems in homogenizing the tumours. At days 4-8, however, there was a dramatic increase in the ratio of the free to bound activities. The results can be explained in terms of the lysosomal theory of intracellular digestion.
D000135:Acid Phosphatase / Q000032:analysis; D000818:Animals; D001551:Benz(a)Anthracenes; D002403:Cathepsins / Q000032:analysis; D005260:Female; D005696:Galactosidases / Q000032:analysis; D005966:Glucuronidase / Q000032:analysis; D008099:Liver / Q000201:enzymology; D008247:Lysosomes / Q000201:enzymology*; D008321:Mammary Glands, Animal / Q000201:enzymology; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000201:enzymology*; D009365:Neoplasm Regression, Spontaneous / Q000201:enzymology*; D011247:Pregnancy; D011270:Pregnancy, Animal; D051381:Rats; D012260:Ribonucleases / Q000032:analysis; D013429:Sulfatases / Q000032:analysis; D014599:Uterus / Q000201:enzymology
D001551:Benz(a)Anthracenes; D012260:Ribonucleases; D000135:Acid Phosphatase; D013429:Sulfatases; D005696:Galactosidases; D005966:Glucuronidase; D002403:Cathepsins