Lysosomal Apparatus in Uterine Muscle: Effects of Estrogen and of Ovariectomy1

Publisher Website
Google Scholar
Abstract
In uterine muscle from nongravid rats, the specific activities of lysosomal enzymes change with ovarian hormonal state and approximate those found in liver. However, in previous morphological studies lysosomes were not found in uterine muscle from cycling rats. In this study we examined the ultrastructure of rat uterine muscle during estrus, after ovariectomy, and after subsequent injection of estrogen and/or progesterone, i.e., under the same experimental conditions used by the author in an earlier biochemical study (Sloane and Bird, 1977). In uterine muscle cells under estrogen domination, lysosomal dense bodies were routinely observed. These cells also had an extensive rough endoplasmic reticulum (RER) and Golgi apparatus as well as many vacuoles and residual bodies. Within 1 day after ovariectomy, coated vesicles and primary lysosomes could be observed budding from the Golgi or GERL (region of tubules between the Golgi and RER from which lysosomes bud). At 3 weeks postovariectomy, the only lysosomal structures present were a few residual bodies. Changes in the number of lysosomes in uterine muscle cells correlated with changes in lysosomal enzyme activities, yet the number of lysosomes did not seem sufficient to account for the enzyme activity, suggesting that lysosomal enzymes in uterine muscle may be stored in the RER, Golgi, or GERL.