Effect of ovarian hormones on lysosomal acid hydrolase activities in rat myometrium
Sloane, B.F.; Bird, J.W.
American Journal of Physiology 232(4): E423-E431
1977
ISSN/ISBN: 0002-9513 PMID: 557904 Document Number: 114478
The activities of the lysosomal acid hydrolases, cathepsin D, acid phosphatase, .beta.-N-acetylglucosaminidase, and .beta.-glucuronidase, were measured in rat myometrium under the following hormonal conditions: during the estrus stage of the estrous cycle (NE); at 1, 2 and 3 wk after ovariectomy; and in 3 wk postovariectomized females after hormone replacement therapy with 17.beta.-estradiol (E2), progesterone (P), or E2 + P. Activities per milligram protein and per milligram DNA of the enzymes were significantly decreased after ovariectomy and were restored to the NE level or above after injecting E2 or E2 + P. Lysosomal enzyme activities did not change with hormonal state in hypophysectomized rats, suggesting that other hormones are required for mediation of enzyme activity. Acid hydrolase activities in other tissues and nonlysosomal enzyme activities in the myometrium did not fluctuate with hormonal state. Studies of lysosomal membrane integrity suggested that one population of lysosomes richer in cathepsin D and acid phosphatase and another rich in .beta.-N-acetylglucosaminidase and .beta.-glucuronidase may be present in rat myometrium. Estrogen seemed to labilize the lysosomal membrane of at least the latter of the 2 proposed populations of myometrial lysosomes.