Estradiol-induced redistribution of lysosomal proteins in rat preputial gland. Evidence from immunologic probes.

Abstract

The influence of estrogen on the subcellular localization and distribution of lysosomal components of preputial gland was investigated in the ovariectomized rat. Antisera of high titer and specificity toward high-density lysosomal lipoproteins of this organ were raised in rabbits. The immunologic effectiveness of the IgG fraction so obtained was confirmed by microcomplement fixation, immunodiffusion, and immunoelectrophoresis. By both direct and indirect immunofluorescence techniques, cryostat sections of preputial gland from the control animals exhibited pinpoint cytoplasmic fluorescence, of dimensions corresponding to those of lysosomes. In contrast, specific immunoreactive material in corresponding target cells from animals receiving 0.1 /zg of estradiol-17fl/100 g body wt only 2 min earlier was distributed more homogeneously, indicating release of antigen from the membrane-bounded organelles. Moreover, specific immunofluorescence became evident at cell surfaces and in peri-and supranuclear localization, sites essentially negative in the controls. These effects were intensified at 15 min, as well as by maximal physiologic dose (0.5 /~g/100 g body wt) of hormone. The relatively less active epimer, estradiol-17a, exhibited only very limited effectiveness by some of these criteria. These observations, taken together with independent biochemical and ultrastructural evidence, lead to the conclusion that structural labilization of lysosomal constituents and their translocation to the nuclear compartment are early correlates of estrogen action.Available biochemical and morphologic evidence indicates that reduced structural latency of components of lysosomes is a rapid response of specific target cells to certain tropic hormones (see reference 25 for review). This process is accompanied by redistribution of constituents so released to the cell surface (14, 15) as well as their access to the nucleus (27,29,31). To extend these observations further, we have analyzed this phenomenon in an estrogen-responsive tissue by immunocytologic methods. By means of specific immunofluorescent probes, the present work demonstrates that mobilization of lysosomes and redistribution of their antigenic components in preputial gland are early manifestations of the administration of physiologic doses of estradiol-17fl to the ovariectomized rat. MATERIALS AND METHODS Animals and Tissue SourcesSprague-Dawley rats were ovariectomized at approx. 6 wk of age and 150 g body wt. They were then maintained under controlled conditions of light and temperature in a low-steroid environment for 3 wk, as previously

Effects of Estradiol and Progesterone on Rat Uterine Ribonuclease Inhibitor Activity

“…RNase activity seen in the E2 treated nuclear fraction, although not significant, was opposite to the E2 effect on all of the other cell fractions. Some investigators (Szego 1972;Szego, Nazareno and Porter 1977) have reported that E2 stimulated an increased lysosomal protein and RNase activity in the nucleus of the ovariectomized rat preputial gland.…”