The histochemistry of complex carbohydrates in the epithelium lining the ventral prostate of the rat

Seasonal changes of the prostate gland in the raccoon (Procyon lotor) inhabiting Hokkaido, Japan

In the prostate gland of the raccoon (Procyon lotor), the morphological appearance of the epithelial cells, such as basal and luminal cells, and the expressions of p63, androgen receptor (AR), and proliferating cell nuclear antigen (PCNA) were examined histologically and immunohistochemically to clarify their seasonal dynamics throughout the year. In this study, the regression with luminal cell defluxion and the regeneration process of the prostatic glandular epithelium was revealed in the seasons with declined spermatogenesis (June to August). The expression of p63 was observed only in the basal cells. AR immunoreactivity in the luminal cells was shown in the developed and regenerating (close to developed) prostates, whereas the basal cells exhibited AR immunoreactivity all year round. PCNA expression was rare in epithelial cells of the developed prostate gland. In the regressed gland, the basal cells demonstrated proliferative ability, whereas PCNA of the luminal cells appeared for the first time in the regenerating phase. This study is the first to clarify the regression with luminal cell defluxion and restoration and the seasonal dynamics of AR expression and proliferative activity in the prostate gland of seasonal breeders.

Expression of prostate glycoconjugates in the stallion and castrated horse

This work was undertaken to determine the glycoconjugates secreted by the epithelium of the prostate in the intact stallion and castrated horse using lectin histochemical procedures in conjunction with enzymatic digestion and deglycosylation treatments. Additionally, anti-5 and 13-16-cytokeratin antibodies were used to localize epithelial basal cells. In the stallion, lectin histochemistry showed the following sugar residues in the Golgi zone of the glandular cells: α-Glu/Man, α-Fuc and β-Gal included in both O- and N-linked oligosaccharides as well as β-GalNAc, GlcNAc and α-Gal, which belonged to O-glycoproteins. β-Gal and β-GalNAc moieties were also noted subterminal to sialyl residues. Sialic acid specific lectins identified Neu-5Ac(α2,3-6)-β-Gal or Neu5Ac(α2,6)-β-GalNAc sequences in both N- and O-bound glycoproteins. The prostatic glandular cells of the castrated horse expressed some of the same sugar moieties found in the stallions, such as α-Glu/Man, α-Gal and GlcNAc, but significant differences were also noted. In particular, β-D-GalNAc was only detected subterminal to sialic acid, β-D-Gal-(1-3)-D-GalNAc was found in N-linked glycans, whereas β-D-Gal-(1-4)-D-GlcNAc and Neu5Acα2,6Gal/GalNAc were noted only in O-glycoproteins. These results indicate that the lectin binding patterns in glandular cells may be modified by sex hormones. No specific lectin labelling of basal cells was found in either the stallion or the castrated horse even though they were immunostained with specific anti-cytokeratin antibodies. These cells stained more strongly in the castrated horse than in the intact stallion suggesting that they are androgen responsive. The glycomolecules detected in the equine prostate secretions may contribute to the remodelling of the sperm surface, which occurs during sperm transit through the male genital tract and also after ejaculation in the seminal plasma. These changes may be important in the understanding of the stallion fertility.

Cytochemical Localization of Glycoconjugates in the Secretory Epithelial Cells Lining the Prostate Gland of the Miniature Pig

The aim of the study was to emphasize several specific functional aspects of the mammalian prostate gland. In this connection, the subcellular localization and characterization of glycoconjugates in the secretory epithelial cells were examined that line the prostate gland of the miniature pig, using cytochemistry, including lectin-gold methods. The results verified a diversified pattern of glycoconjugates in the structures of the secretory cells. The secretory granules and the free surface coat of the plasma membrane contained several sugar moieties such as alpha-D-Man, alpha-D-Glc, alpha-L-Fuc, beta-D-Gal, GalNAc, GlcNAc and NeuAc (sialic acid), whereas the Golgi apparatus exhibited GlcNAc and sialic acid residues. In addition, the cisterns of the endoplasmic reticulum showed alpha-D-Man and alpha-D-Glc moieties. It seems likely that the secretory glycoconjugates demonstrated contribute to favourable conditions for fertilization.

Comparative study of glycoconjugates of the rat prostatic lobes by lectin histochemistry

BACKGROUND

The rat prostate gland is composed of several distinct lobes: the ventral, lateral, dorsal, and anterior (also called the coagulating gland). Each prostatic lobe is different in its morphology, secretions, and response to hormones.

METHODS

The present study characterized and compared the expression of glycoconjugates in three different lobes (ventral, lateral, and dorsal) of the Noble rat prostate gland by lectin histochemistry, using a battery of 30 different lectins.

RESULTS

The results indicate that different prostatic lobes elaborate and secrete different glycoconjugates. The dorsal prostatic epithelium secretes mainly in an apocrine mode, as characterized by the presence of apical cytoplasmic blebs which are absent in the other two lobes, though merocrine secretion is also suggested. These cytoplasmic blebs were rich in Man, GlcNAc, Gal/GalNac, Fuc, NeuAc(alpha2,6)Gal, and oligosaccharides. Two types of cytoplasmic belbs were also identified according to their lectin bindings: blebs stained by S-Con A, LCA, PWA, UEA-II, RCA-I, DBA, ECA, WFA, Jacalin, MPA, SJA, LTA, UEA-I, PHA-E, and PHA-L, and some blebs stained by S-WGA, SBA, HAA, HPA, VAA, BPA, MAA, and SNA. The lectins, which reacted with the second type of blebs, also revealed some cytoplasmic granules in the dorsal prostatic epithelial cells. The epithelium of the lateral prostate showed weak or negative reactions to lectins, suggesting that it may express fewer glycoconjugates as compared to the other two lobes. The epithelial Golgi region of the ventral prostate is the most developed among the three lobes, and contained abundant GlcNAc, alpha/beta-GalNAc, and NeuAc(alpha2,6)Gal residues, as shown by its intense reactions to S-WGA, DBA, SBA, HAA, HPA, WFA, and SNA. GS-I-B4 reacted specifically with the basal epithelial cells in all three lobes, indicating that glycoconjugates with terminal alpha-Gal/GalNAc were commonly expressed in these basal cells. The basal cells in ventral prostate might express more complex glycoconjugates, as they were also stained by PWA, RCA-I, ECA, and PHA-L, in addition to GS-I-B4, suggesting that these basal cells contained more Gal(beta1,4)GlcNAc and Gal(beta1,4)GlcNAc(alpha1,2)Man residues. GS-I-B4 and PHA-L also demonstrated a differential staining of the stromal smooth muscles and their associated extracellular matrix in the three prostatic lobes, suggesting that these structural components in different prostatic lobes were different in their complex oligosaccharide contents, which probably has an influence on the epithelial-stromal interaction in the prostate.

CONCLUSIONS

In summary, the present study has established for the first time the expression patterns of glycoconjugates in the three lobes of the Noble rat prostate gland and suggests that certain lectins are useful as histochemical markers for the three individual prostatic lobes.

Glycoconjugate histochemistry of the prostate gland in the pig

In the porcine prostate, glycoconjugates elaborated and released by the glandular cells have been studied by means of a series of histochemical methods of light microscopy. The employed methods included several routine procedures in combination with digestion by carbohydrate-degrading enzymes and peroxidase-labelled lectin diaminobenzidine procedures. In the glandular tissues, the particular glycoconjugates were shown to be secretory glycoproteins which contained vicinal diol, sulphate, and carboxyl groups and were provided with different saccharide residues such as alpha-D-mannose, alpha-D-glucose, lactose, N-acetyl-D-galactosamine, beta-D-galactose, alpha-L-fucose, N-acetyl-D-glucosamine, and N-acetyl-neuraminic acid. These glycoconjugates were, likewise, found to exhibit positive reaction for proteins. The present histochemical results have been discussed with special reference to the histophysiological functions performed by the prostate gland in the pig.

Morphologic and regulatory aspects of prostatic function

Current concepts of the structural and functional organization of the human prostate are presented and are related to endocrine principles which have been studied in experimental animals. Based on embryological and histological studies, the internal structure of the human prostate gland is divided into four subdivisions: 1. the anterior nonglandular fibromuscular stroma. 2. the periurethral portion, 3. the peripheral zone, and 4. the central zone. The central zone which accounts for 25% of the gland, is formed by a wedge-shaped group of ducts, arising close to the orifices of the ejaculatory ducts and is surrounded by the peripheral zone (75% of the gland). The functional interdependence and relationship between the stroma and the epithelium observed during embryological development, postnatal maturation and under certain pathological conditions, has led to the concept of a functional prostatic unit, which is useful for the explanation of prostatic growth and the expression of specific genes. There is growing evidence of a functional heterogeneity within the prostatic secretory duct system, with a concentration of estrogen-sensitive cells close to the urethra, and a relatively long persistence of undifferentiated nonsecretory acini at the peripheral tips of the gland ducts close to the dorsal capsule until late puberty. Secretory and proliferative activities of the gland are strictly androgen-dependent. Of particular importance with respect to glandular and stromal proliferation are the recent reports on the presence of different growth factors in the prostate. Hormonally induced imbalances in the system of growth factor production, androgen- and estrogen-dependence and general ageing of the cells have to be taken into consideration in understanding various prostatic pathologies such as benign prostatic hyperplasia and prostate cancer.

Localization of a normal prostatic secretory product using the monoclonal antibody KR-P8

We previously reported that the monoclonal antibody KR-P8 detects a prostate organ-specific antigen that is distinct from other markers such as prostatic acid phosphatase and prostate specific antigen. In this report we demonstrate that the antigen recognized by KR-P8 is among the secretory products of both normal and malignant prostatic epithelium. Immunoperoxidase staining patterns showed that the antigen was concentrated on the luminal surfaces of the glandular epithelial cells of prostate, and also that the antigen was localized within secretory vacuoles of cells of the prostate tumor line PC3. In addition, using an immunoblotting assay the KR-P8 binding antigen was detected in the growth media of PC3 cells and also found to be present in human urine and seminal plasma. The data suggest that the antigen recognized by KR-P8 may be a useful marker for studying the secretory processes of the prostate gland.

Complex carbohydrates in the secretory epithelium of the goat prostate

The complex carbohydrates in the epithelium of the goat prostate were studied with a battery of light microscopical histochemical methods that included peroxidase-labelled lectin-diaminobenzidine (PO-LT-DAB) procedures. The secretory epithelial cells were found to be of three types: (a) mucus-producing cells, (b) protein-secreting cells, and (c) cells intermediate between (a) and (b). All these cell types contained variable amounts of neutral and acidic complex carbohydrates. The histophysiological significances of these substances in the glandular cells are discussed with special reference to the function of the accessory sex glands.

Carbohydrates in the epithelium lining the seminal vesicle of the rat as studied by histochemical methods of light and electron microscopy

In the epithelium lining the seminal vesicle of the rat, carbohydrates have been studied by means of histochemical methods of light and electron microscopy. In light microscopy, the free surface and granules of different sizes in the distal cytoplasm of the epithelial cells and lumenal masses of secretions were shown to exhibit positive reactions for carbohydrates with 1,2-glycol and acidic groups and sialic acid residues. In electron microscopy, the surface coat of the plasma membrane, certain elements of the Golgi complexes, dense cores of secretory granules and glycogen particles in the epithelial cells were found to exhibit positive reactions for carbohydrates with 1,2-glycol groupings. The correlated structures and functions of the carbohydrate-containing components have been discussed in the light of the known physiology of the seminal vesicle in the rat.