the ultrastructure of the accessory sex organs of the male rat

Z. Zellforsch. 144, 167--178 (1973) © by Springer-Verlag 1973

The Uhrastructure of the Accessory Sex Organs of the Male Rat

IX. The Pos t - ca s t r a t i on I n v o l u t i o n of the Vent ra l , La te ra l and the Dorsal P ros t a t e

Erik DaM and Asmund Kjaerhe im

Department of Anatomy and Pathology, Dental Faculty, University of Oslo, Norway

Received January 15, 1973

Summary. The ventral, lateral and dorsal lobes of the rat prostate were studied 2, 3, 5, 7 and 21 days after castration. The major changes were a general reduction of the Golgi area and the RELY. The cells became pale and contained less organclles compared with the normals. One of the most conspicuous changes were enormous autophagic vacuoles which were present already after 2 days, seemed to reach a numerical peak 3 days after castration and were seldom encountered after 7 days. Increased number of dense bodies were found within the san~le period. Lipid droplets were observed in the basal cytoplasm of the epithelial cells, especially in the ventral lobe. The basal cells showed the same involution as in the ordinary epithelium. In addition, macrophagcs were relatively numerous, and between the epithelial cells also lymphocytes were found. The results are discussed in relation to biochemical data on the different lobes.

Key words : Prostate - - Rat - - Castration - - Alterations - - Electron microscopy.

Introduction

The Normal development and funct ion of the prostate gland depend upon an appropriate amoun t of circulating androgen. Bilateral orchidectomy causes a rapid a t rophy of the prostate, and reduct ion of the secretory act ivi ty. While these invo lu t ionary changes have been throughly invest igated by light microscopy (for ref. see Price and Wfll iams-Ashman, 1961), there are only a few electron microscopic studies dealing with this problem. Ul t ras t ruc tura l changes in the vent ra l prostate following castrat ion were studied by Hark in (1957), Brandes, Gy6rkey, Groth (1962) and Helminen and Ericsson (1971). The fine s t ructure of the lateral and dorsal prostate has previously no t been examined following gonadectomy.

The present paper, is a par t of a series on the u l t ras t ruc ture of the prostatic complex and describes the post-castrat ion involu t ion of the ventral , lateral and dorsal prostate.

Materials and Methods Twcntyone albino male rats (derived from the Charles River CDF strain) 4~6 months

old, were used in this study. Fifteen rats were castrated through a scrotal incision 2, 3, 5, 7 and 21 days prior to examination, the remaining six were normals, used as controls. Each group consisted of 2 4 animals. While in aether anesthesia, the aorta was canulated, and intraaortic fixation perfusion was carried out as described by Dahl, Kjaerheim and Tveter (1973). The dissection of the prostate, the preparation of the samples and the electron microscopic techniques were according to the principles already reported (Dahl et al., 1973).

168 E. Dahl and ~. Kjaerheim

Observations All the observations made in this s tudy were compared with the observations

made in the normals (see Dahl et al., 1973). Although the castration had a specific effect on the different cell types of the various lobes, and also showed variations as to the sensitivity to castration, there were several common features. Generally the cells were pale, contained less organelles as compared with the normMs, with reduction both of the cell height and width, with loss of cytoplasm. The major changes were reduction of the Golgi area and the RER, in addition to a marked general reduction of the number of secretion granules as well as the number of free ribosomes. The nuclei tended to be smaller than normal with inden- tations. Intranuclear inclusions were relatively frequently seen. The basal cells showed the same involution as in the ordinary epithelium. In addition, macro- phages were relatively numerous, and between the epithelial cells also some lymphoeytes were found.

The Ventral Prostate

The first distinct changes within the rough endoplasmic reticulum (RER) were seen already after 2 days, appearing as whorl formations, which consist of concentric, lamellated configurations of REI~ profiles (Figs. 1, 2). Lysosome-like bodies and vacuoles were sometimes found in the central portion of these characteristic profiles. In addition, there seemed to be a numerical reduction of the REI~ profiles (Figs. 1 4 ) with decrease of free ribosomes. After 3 weeks, only remnants of REI~ were found.

The Golgi Area and Secretion Granules. Two days after castration, the Golgi apparates was reduced, with smaller and often empty vacuoles (Fig. 1). These changes were more accentuated with increasing tinle after castration, but even after 7 days, the Golgi area was rather distinct in a few cells. The number of secretion granules were concentrated apicMly (Fig. 2) and were encountered even after 7 days. Their number was now, however, distinctly reduced. After 3 weeks, the Golgi area was small, and the vacuoles often totally collapsed (Fig. 5). Se- cretion granules were at this t ime only rarely encountered.

Autophagie Vacuoles and Dense Bodies. Antophagie vacuoles represented a typical and constant feature of the postcastration involution of the ventral prostate. They were present already after 2 days (Figs, 1, 2), and seemed to reach a numerical peak 3 days after castration (Fig. 3). They were also present after 5 days, but were rare after 7 days. Dense bodies were found within the same period (Figs. 1-3). After 3 weeks, very few dense bodies were seen.

Lipid Droplets. Three weeks after castration, the cells contained enormous quantities of fat (Fig. 5) which were not observed at the earlier intervals in the ventral prostate.

The Lateral Prostate

The Endoplasmic Reticulum. Similarly as to the ventral lobe, the first changes within the rough endoplasmic reticulum (RER) appeared as whorl formation; with centrally located lys0some-like bodies and vacuoles (Figs. 6-8) as seen after 2 days. At later intervals there was a distinct reduction of the lZER profiles (Fig. 9), and after 21 days only remnants were occasionally encountered.

Fig. t. Survey electron micrograph of the ventral prostate two days after castration. There is a general reduction in the amount of cytoplasm, reduction of the Golgi area (G) and of the rough endoplasmic reticulum (RER). Increase in the amount of dense bodies (Db). Note the small autophagic vacuole (arrow). N nucleus. L acinar lumen. Bm basal membrane. × 9000

Fig. 2. Survey micrograph of the apical part of the epithelium of the ventral prostate, 2 days after castration. Note the initial involuntary changes: Whorl formation (arrows) and the autophagie vacuoles (AV). Secretion granules (SG) adjacent to the lumen (L). N nucleus.

× 7 500

12 Z. Zellforsch., Bd. 144

Fig. 3. Wi th in 2-5 days after castration giant autophagic vacuoles (A V) often located in the Golgi area. They are well demarcated from the surrounding cytoplasm, and may contain large dense bodies together with unidentified cytoplasmic material. There is reduction of the RER. The content of the l~ER-cisterna appears more electron dense than in normals.

3 days after castration. N nucleus, x 12500

Fig. 4. Five days after castration, the l ight and the width of the cells are markedly reduced. Complex bodies (Cb) may be seen. The Golgi area (G) is small, the cytoplasm pale, increase

of the number of dense bodies (Db). L acinar lumen, iVb nuclear body. X 10000

Fig. 5. After 21 days the cells appear very small, almost completely deprived of leER and other organelles. Lipid droplets (L) are regularly encountered. The Golgi apparatus (G) is

completely collapsed. L lumen of the alveolus. × 16000

Fig. 6. Also in the lateral prostate reduction of the RER, and whorl formation (arrow) often with a dense body in the center, are the first changes observed. Reduction of the secretion granules (SG), the brush-border (Bb) may appear fuzzy. N nucleus. L lumen of the alveolus.

Db dense bodies, x 9200

12"

172 E. Dahl and A. Kjaerheim

The Golgi Area and Secretion Granules. In the Golgi area changes could be seen after a post-castration periode of three days (Fig. 6). In some cells the secretion granules were relatively small in comparison with the vacuoles in which they were located. Even 7 days after castration some dense secretion granules were occasionally encountered at the apical part of the cells. However, in other cells at the same time, a considerable reduction of the Golgi area and totally absence of secretion granules were found (Fig. 9). Three weeks after castration the Golgi region was very smMl, most often seen as remnants only.

Dense Bodies and Autophagic Vacuoles. At all times investigated, lysosomes were found (Figs. 6-9). After 5 days, accumulation of numerous dense bodies (giant lysosomes ?) were seen (Fig. 10) and also numerous microbodies which appeared more or less degenerated (Fig. 11). After 21 days accumulations of large complex bodies were regularly seen (Fig. 12).

The Dorsal Lobe

The Endoplasmic Reticulum. The first days after castration, no convincing changes were seen in the rough cndoplasmic reticulum (RER). After five days and even more after 7 days, the R E R cisterna were reduced considerably, both in number and sizes. After 21 days, there were only remnants of the R E R left (Fig. 16).

The Golgi Area. Generally, the Golgi apparatus seemed not to be reduced in size before 5 days. However, at this time, cells were found with only remnants also of this structure. After three weeks it was markedly reduced in all the cells, and secretion granules were totally absent (Fig. 16).

Autophagic Vacuoles and Dense Bodies. Also in this lobe one of the most conspicuous changes were enormous autophagic vacuoles of similare appearance as in the ventral lobe (see Fig. 3). They were present in many cells as early as 2 days after castration. At this time, irregular structures seemed to segregate parts of the cytoplasm (Fig. 13). After 3 days, the number of autophagic vacuoles seemed to be reduced. They were occasionally encountered after 7 days, but they were not observed after 21 days.

Already the second day, small dense bodies were seen. They increased in number, and were numerous after 5 days. After 5 days, the dense bodies seemed to be of different sizes, the largest bodies were preferentially located in the apical par t of the cells (Figs. 14-15), often in the vicinity of the Golgi area, while the smaller tended to be localized hasMly. After 21 days numerous dense bodies and complex bodies were regularly and frequently encountered.

Lipid Droplets. Already after 3 days lipid droplets were occasionally seen in a few cells. However, there did not seem to be any increase by the time after castration. Nuclear inclusions different from ordinary nuclear bodies were occasionally encountered.

Blebbing. At the surface of the cells, blebbing was less pronounced than in the normal animals, and blebbing was markedly reduced by the post-castration period.

:Figs. 7 and 8. Demonstrate different types of whorl formation. They are bui l t up of concentric lamellated configurations of the R E R with lysosome-like dense bodies and vacuoles of different sizes in the center. :Fig. 7 : 2 days after castration. × 20000. Fig. 8 : 5 days after castra-

tion. × 20000

:Fig. 9. Survey micrograloh of the laterM prostate 7 days after castration. Note the marked reduction in all the different organelles, with increase of dense bodies (Db). (Cfr. Fig. 6.)

N nucleus. Bb brush border. × 5000


Fig. 10. In some cells of the lateral prostate numerous large dense bodies (giant lysosomes ?) occur 5 days after castration. × 7500

Fig. 11. Lateral lobe. After 7 days, some cell contained numerous microbodies which appeared more or less degenerated. × 12000

Fig. 12. After 21 days, accumulations of membrane-limited complex bodies were seen, containing myeline-like structures, amorphous dense material and lipid-like components.

× 12000

Discussion

Our knowledge of the mode of action of steroid sex hormones has increased substantially during the past decade. I t is now ample evidence that in target tissues, increased RNA-synthesis is one of the first detectable effects after ad- ministration of testosterone and oestradiol to male and female animals, respec- tively. This effect which may be demonstrated within the first hour after injection of the hormone (Liao and Stumpf, 1965) appears to be principally mediated via the nucleus. The works of Liao and Stumpf (1965) strongly indicate that nucleolus- associated chromatin may be intimately related to the enhanced RNA-synthesis caused by testosterone. On the other hand, withdrawel of the androgenic stimulus results in a rapid reduction of the t~NA-content of the prostate (Williams-Ashman, 1965). Testosterone will also stimulate the DNA-synthesis, but this effect is observed only after a few days (Coffey, Shimazaki, Wil]iams-Ashman, 1968). Following castration, the DNA-eontent is not reduced to the same extent as the RRTA, indicating that the cytoplasm has been subjected to more extensive alterations th~n the nuclei (Coffey et al., 1968). A prerequisite for these biological effects is probably the association of androgen with specific androgenic receptors located both in the nuclei and the cytoplasm of the prostate (Tveter et al., 1970).

Post-castration Involution of the Rat Prostate. I I 175

Fig. 13. Also in the dorsal prostate the first changes were irregular membrane-like structures which segregate parts of the cytoplasm proceeding the autophagic vacuoles (arrows). The

RER-cisterna appeared smaller than normal. 2 days after castration. × t6000

Figs. 14 and 15. Demonstrate large mierobodies containing myeline-like figures which were seen early in the post-castration period. Fig. 14. 2 days after castration. ×40000. Fig. 15.

2 days after castration. × 50000

The reduced amount of free ribosomes and the a t rophy of the R E R demonstrated in the present report are in accord with these biochemical data. Already two days after castrat ion the ground cytoplasm looked pale due to loss of ribosomal particles, and the I~ER profiles were significantly changed. The alterations of the t~ER were apparent ly of two kinds. For the first, there seemed to be a t rophy of the REI~ with numerical reduction of the t~EI~ profiles. The distance between adjacent REt~ profiles was enlarged, which together with the general simpli- fication of the cytoplasm due to loss of organelles, caused the characteristic castration-picture. These quant i ta t ive alterations of the R E R were in the present s tudy more prominent than qualitative changes. Szirmai and van der Linde (1965) reported a partial degranulation of the I~ER after castration with large portions of the R E R membrane profiles free of ribosomal particles. These changes were seen 3 days after gonadectomy, but were still visible after 6 months. I n the present s tudy, using intraaortic perfusion fixation, such degranulat ion was no prominent feature. I n some areas the number of ribosomes covering the R E R membranes was reduced, but large portions free of ribosomes were not seen. Transition to a smooth form of I~ER did not seem to occur. Collapse of the R E R eisternac has been described as a typical finding early in the post-castrat ion period


Fig. 16. Survey electron micrograph of the dorsal lobe 5 days after castration. There is a general reduction of the amount of cytoplasm, reduction of the Golgi area (G) and especially of the rough endoplasmic reticulum (RER). Several types of pigment bodies, increased in

number. Db dense body. Cb complex body. N nucleus. L acinar lumen. × 5000

Post-castration Involution of the Rat Prostate. II 177

(Harkin, 1957; Brandes etal . , 1962; Helminen and Ericsson, 1971). The width of the ]~ER eisternae may, according to our results, show variations from cell to cell as well as in different regions of the same cell, both in the intact (DaM et al., 1973) and the castrated rat. In the castrated animal there is, however, a tendency to have more collapsed eisternae. The increased distension of the apical REI~ eisternae of the ventral prostate which has been described to take place during the first two days after castration (Harkin, 1957; Brandes et al., 1962) was not observed in the present study, probably due to the use of a different fixation technique.

The second alteration observed with the R E R was the formation of concentric lamellated configurations of R E R profiles. Helminen and Ericsson (1971) described such whorl formation to be a characteristic feature of the post-castration involution of the rat ventral prostate. These whorls were transformed to autophagie vacuoles partially by the action of lysosomes, with autodigestion of a substantial part of the cytoplasm. The present study confirms that whorl formation of the I~EI~ is a characteristic finding in the ventral prostate relatively early after orchideetomy. Furthermore, our results also demonstrate that whorls formation takes place in the lateral and dorsal prostate as well. Similar changes are also found in the seminal vesicles following gonadoeetomy (Dahl et al., 1973). The arrangement of the R E R to form such whorls therefore seems to be an ex- pression of a general involutionary process in androgen target organs deprived of their hormonal stimulus. Our mierographs revealed that the diameter of the t~ER eisternae in the whorls had a varying size. Whereas the R E R eisternae often were collapsed, broad REI~ eisternae were also frequently seen, indicating tha t these R E R profiles are still capable of producing a proteinaeeous material, and that whorl formation is not restricted only to collapsed t~Et~.

In the central portions of the I~EI~-whorls, signs of cytoplasmic dissolution were observed in many cells. Sometimes lysosome-like bodies were seen closely associated with such areas, while in other instances, cellular autophagy apparently took place without the presence of lysosomes. This antophagy and cytoplasmic dissolution seemed to start in the center of the whorls, with gradually increasing size of the area to be digested. The findings seem to support strongly the sug- gestions of Helminen and Ericsson (197 i) that the RERwhorls may be transformed into autophagic vacuoles. The present findings also indicate tha t autophagie vacuoles may be formed by another different mechanism, too. Thus, in many places, segregation of a part of the cytoplasm was obvious. In such demarcated regions, the cytoplasm was often dissolved and the normal structure was lost The sequestrated area was demarcated by one or more myeline-like membranes as characteristic for cellular autophagy. Autophagie vacuoles were often located in the supranuelear region of the cells, and not seldom closely associated with the Golgi region. They were early signs of cellular autophagy, being numerous two or three days after castration, and significantly reduced in number as well in size after 5 days. At this time, the majori ty of the dense bodies were of the residual body type.

Reduction of the Golgi complex was another constant finding in the castrated animals. The diameter of the Golgi vacuoles was diminished, and more so with increasing lapse of t ime after removal of the testes. Another feature indicating


reduced funct ion of the Golgi a p p a r a t u s was a d i s t inc t decrease in the number and size of the secret ion granules in the Golgi area. Similar f indings have been r epor t ed b y H a r k i n (1957) and Brandes et al. (1962). A r emarkab le f inding was t h a t as la te as 7 days af ter g o n a d e c t o m y secret ion granules were stil l encountered in some cells. A large accumula t ion of secret ion granules a t the surface of the cells has been in t e rp re t ed as ea r ly pos t - cas t r a t ion changes (Brandes et at., 1966 bu t m a y also be encounte red in no rma l non-cas t r a t ed animals (Dahl et al., 1973).

References Brandcs, D., Gy6rkey, F., Groth, D.: Fine structural and histochemicM study of the effect

of castration on the rat prostatic complex. Lab. Invest. l l , 339-349 (1962) Coffey, D.S., Shimazaki, H., Williams-Ashman, H. G.: Polymerization of deoxyribonucleotidcs

in relation to androgen-induced prostatic growth. Arch. Biochem. Biophys. 124, 181-198 (1968)

Dahl, E., Kjaerheim, A., Tvetcr, K.J. : The ultrastructure of the accessory sex organs of the male rat. I. Normal structure. Z. Zcllforsch. 187, 345-359 (1973)

Dahl, E., Tveter, K.J. : The ultrastructure of the accessory sex organs of the male rat. I IL The post-castration involution of the coagulating gland and the seminal vesicle. Z. Zell- forsch. 144, 179-189 (1973)

Harkin, J.C.: An electron microscopic study of the castration changes in the rat prostate. Endocrinology 60, 185-199 (1957)

Helminen, H.J. , Ericsson, J.L.E.: Ultrastructural studies on prostatic involution in the rat. Mechanism of autophagy in epithe]iM cells, with special reference to the rough-surfaced endoplasmic retieulum. J. Ultrastruct. l~es. 86, 708-724 (1971)

Liao, S., Stumpf, W. E.: Autoradiographic evidence for the selective enhancement of nucleolar ribonncleic acid synthesis in prostatic nuclei by testosterone. Endocrinology 88, 629-632 (1968)

Price, D., Williams-Ashman, H. Gj.: The acessory reproductive glands of mammals. In: Sex and internal secretions (Young, W.C. ed.), 3rd ed., vol. I, p. 366~148. Baltimore: Williams & Wilkins Co. 1961

SzirmM, J.A., yonder Linde, P.C.: Effect of castration on endoplasmic reticulum of the vesicle and other target epithelia in the rat. J. Ultrastruct. l~es. 12, 380-395 (1965)

Tveter, K.J. , Unhjem, 0., AttramadM, A., Aakvaag, A., Hansson, V.: Androgenic receptors in rat and human prostate. Advanc. Biosci. 7 (1970)

YVilliams-Ashman, H.G.: Androgenic control of nuclei acid and protein synthesis in male accessory genital organs. J. cell. comp. Physiol. 1, 111-124 (1965)

Dr. Erik Dahl Department of Anatomy Dental Faculty University of Oslo P.O. Box 1052, Blindern Oslo 3, Norway

the ultrastructure of the accessory sex organs of the male rat

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