[The proteinase activity and content of trypsin inhibitors in the mammae of female rabbits in physiological states].
We studied the activity of lysosomal cathepsins B and D, neutral trypsin-like proteinase, and the content of trypsin inhibitors in the mammary glands of virgin, pregnant, and lactating rabbit females, as well as during the involution caused by lactostasis. The maximal activity of cathepsin D was found to occur in mammary glands under the condition of lactostasis. The activity of cathepsin B was practically identical in the mammary glands of virgin and pregnant animals and diminished during lactation. The activity of trypsin-like proteinase is low in the mammary glands of virgin animals, increases drastically during pregnancy, and diminishes during lactation. The content of trypsin inhibitors is maintained at a similar level in the mammary glands of virgin and pregnant animals and increases significantly during lactation. The caseinolytic activity of neutral proteinases has not been detected in the mammary glands of virgin rabbit females. At the lactation and involution stages, it is considerably lower than the activity of acidic proteinases and is possibly controlled by endogenous inhibitors.
Markovich
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D000818:Animals; D010450:Endopeptidases / Q000032:analysis / Q000378:metabolism*; D005260:Female; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007774:Lactation / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000737:chemistry / Q000201:enzymology*; D011247:Pregnancy; D011817:Rabbits; D013379:Substrate Specificity; D014361:Trypsin Inhibitors / Q000032:analysis / Q000378:metabolism*
D014361:Trypsin Inhibitors; D010450:Endopeptidases