Immunocytochemical demonstration of insulin or insulin-like immunoreactivity in the rat prostate gland

Quantification of endocrine cells and ultrastructural study of insulin granules in the large intestine of opossum Didelphis aurita (Wied-Neuwied, 1826)

This study aimed to investigate the distribution of argyrophil, argentaffin, and insulin-immunoreactive endocrine cells in the large intestine of opossums (Didelphis aurita) and to describe the ultrastructure of the secretory granules of insulin-immunoreactive endocrine cells. Fragments of the large intestine of 10 male specimens of D. aurita were collected, processed, and subjected to staining, immunohistochemistry, and transmission electron microscopy. The argyrophil, the argentaffin, and the insulin-immunoreactive endocrine cells were sparsely distributed in the intestinal glands of the mucous layer, among other cell types of the epithelium in all regions studied. Proportionally, the argyrophil, the argentaffin, and the insulin-immunoreactive endocrine cells represented 62.75%, 36.26%, and 0.99% of the total determined endocrine cells of the large intestine, respectively. Quantitatively, there was no difference between the argyrophil and the argentaffin endocrine cells, whereas insulin-immunoreactive endocrine cells were less numerous. The insulin-immunoreactive endocrine cells were elongated or pyramidal, with rounded nuclei of irregularly contoured, and large amounts of secretory granules distributed throughout the cytoplasm. The granules have different sizes and electron densities and are classified as immature and mature, with the mature granules in predominant form in the overall granular population. In general, the granule is shown with an external electron-lucent halo and electron-dense core. The ultrastructure pattern in the granules of the insulin-immunoreactive endocrine cells was similar to that of the B cells of pancreatic islets in rats.

Morphologic characterization and distribution of endocrine cells in the large intestine of the opossum Didelphis aurita (Wied-Neuwied, 1826)

This study was designed to investigate the morphology and distribution of argyrophil, argentaffins, and insulin-immunoreactive endocrine cells in the large intestine of the opossum Didelphis aurita. Fragments of the large intestine of 10 male specimens of the opossum D. aurita were collected, processed, and submitted for histochemistry, immunohistochemistry, and scanning electron microscopy. The tunics of the large intestine of D. aurita presented morphological characteristics that have already been described for eutherian mammals. The morphometric data showed that the inner circular layer of all portions and regions analyzed is thicker relative to the longitudinal layer, and these layers in the rectum are thicker compared to the cecum and ascending colon. The majority of mucus-secreting cells have acid and neutral mucins, suggesting that the production of mucus is mixed. The number of these cells increases in the region of the cecum toward the rectum. Important findings include the occurrence of argyrophil, argentaffins, and insulin-immunoreactive endocrine cells in all segments of the large intestine of the opossum (D. aurita). To the best of our knowledge, this is the first report about the presence of insulin-immunoreactive endocrine cells in the large intestine of the opossum (D. aurita).

Endocrine cells and nerve ganglia of the small intestine of the Opossum Didelphis aurita Wied-Neuwied, 1826 (Mammalia: Didelphidae)

The nervous and endocrine systems jointly control intestinal movements, secretions of their glands and also participate of the processes of nutrient digestion and absorption. Therefore, the central objective of this study was to verify the existence of a possible relationship between the number of nervous cells and ganglia of the submucosal and myenteric plexuses and the number of endocrine cells in the small intestine of adult D. aurita. The utilized staining techniques were Grimelius, modified Masson-Fontana, direct immunoperoxidase and H-E. Argyrophillic, argentaffin and insulin immunoreactive endocrine cells do not numerically vary between the initial, mid and final regions of the duodenum, jejunum and ileum (P>0.05), except for argyrophillic cells in the jejunum (P>0.05). No numerical relationship has yet been verified between the number of nerve ganglia and endocrine cells, and also between nervous and endocrine cells. We recommended the use of new immunohistochemical techniques to confirm the numerical correlation between the nervous and endocrine systems in the small intestine. The morphology and distribution of endocrine cells and the nerve ganglia studied were similar to those encountered in eutherian mammals.

Prostate gland: structure, functions and regulation

The prostate gland plays an important role in male reproduction. It secretes enzymes, lipids, amines and metal ions essential for the normal function of spermatozoa. Development, differentiation and maintenance of the prostate gland depend on steroid and peptide hormones. Beside hormones growth factors also regulate the prostate gland. This review will focus on the structure, functions and mode of regulation of the prostate gland.

IGF-I and IGF-binding proteins: stimulatory and inhibitory factors secreted by human prostatic adenocarcinoma cells

Deregulation of growth observed in malignant cell cultures has been assumed to be the result of increased secretion by these cells of autocrine growth factors, as well as the decreased sensitivity of these cells to inhibitory molecules which are diffused from normal or transformed cells. Our results show that PC-3 cells secreted into the medium, factors having stimulatory and inhibitory activities. We found an IGF-like molecule in medium conditioned by PC-3 cells. Its concentration was less than 1 ng/ml of conditioned medium. We demonstrated that PC-3 cells have receptors for IGF-I and are stimulated by this growth factor. However, the dose response curve shows that 1 ng/ml of IGF-I is not sufficient to indicate autocrine growth regulation by IGF of prostatic carcinoma cells. IGF-binding proteins of 90,000, 45,000, 34,000 and 28,000 molecular weight were also secreted by PC-3 cells. It is noteworthy that the secreted proteins which had the greatest inhibitory effect on chick embryo fibroblast growth also has the strongest IGF-binding activity. The probability that the IGF-binding protein secreted by PC-3 cells inhibited serum stimulation of DNA synthesis by preventing stimulation induced by IGF present in the serum is discussed. It is of interest that these IGF-binding proteins inhibited chick embryo fibroblast proliferation but did not inhibit PC-3 cells. This is in agreement with the assumption that IGF present in the medium is not an autocrine growth factor for these cells.

Serum-free culture of enriched mouse anterior and ventral prostatic epithelial cells in collagen gel

Sustained growth of mouse ventral and anterior prostatic epithelial cells embedded within collagen gel matrix was achieved in a serum-free medium composed of Dulbecco's modified Eagle's medium and Ham's F12 medium, 1:1 (vol/vol), supplemented with bovine serum albumin fraction V, epidermal growth factor, transferrin, cholera toxin, prolactin, 5 alpha-dihydrotestosterone, cortisol, putrescine, fibroblast growth factor, and a trace element mixture. Three-dimensional growth of prostatic epithelial cells occurred inside the collagen gel matrix. This serum-free medium allowed cell growth greater than sevenfold over 10 d in culture. Tissue recombination and cell culture techniques were integrated to demonstrate that cultured cells retained prostatic characteristics. Following 10 d of culture, epithelial colonies from mouse ventral and anterior prostatic epithelial cell cultures were isolated and combined with rat fetal urogenital sinus mesenchyme and grown for 4 wk under the renal capsule of intact athymic male mice. These tissue recombinants showed distinctive prostatic histologic characteristics (alveoli and ducts lined with cuboidal or columnar epithelium surrounded by stroma). When histologic sections of recombinants were stained with the Hoechst 33258, epithelial cells of mouse origin were distinguishable from stromal cells of rat origin.

Immunocytochemical localisation of follicle stimulating hormone (FSH) in normal, benign and malignant human prostates

Immunocytochemical localisation of follicle stimulating hormone (FSH) was carried out in normal, benign and malignant human prostates by indirect immunoperoxidase technique. Positive staining was observed in the epithelial cells of all the three categories, while the stromal cells showed a weakly positive reaction in a few specimens. The brown reaction product was dispersed in the cytoplasm of the epithelial cells. These observations demonstrate the presence of immunoreactive FSH-like peptide in human prostate. The significance of FSH in the aetiopathology of prostatic disorders is discussed.

De novo biosynthesis of FSH like peptide by the human prostate

Human benign prostatic hyperplasia tissue is able to synthesize immunoreactive FSH (IR FSH) in vitro. The prostatic FSH is similar to pituitary FSH as evident by co-elution on Sephadex G-100. High performance gel filtration chromatography and Western blot analysis. Immunocytochemical localization studies indicate positive staining in the cytoplasm of prostatic epithelial cells. There is a two fold increase in the concentration of immunoreactive FSH in benign hyperplastic tissue as compared to normal prostate.