Immunohistochemical studies on brain nitric oxide synthase (bNOS) in the male genital accessory glands of the rat during postnatal development

The aim of the study was to investigate the presence, localisation and function of brain nitric oxide synthase (bNOS) in the male genital accessory glands of rats in the course of their postnatal development. Localisation of the bNOS was immunocytochemically investigated in the epididymis, seminal vesicle and ventral prostate of male Wistar strain rats at 1, 5, 10, 20, 28, 35, 45 and 59 days of age. The method employed involved mouse monoclonal antibodies against rat bNOS in combination with tyramide signal amplification (CSA). The intensity of the reaction in the organs studied was determined using computer software to demonstrate the optical density of the reaction product obtained. In the epididymis a weak reaction was observed in the connective tissue/muscular sublayer on the 28th and 45th days of life. In the seminal vesicle and ventral prostate a positive reaction appeared in the epinuclear portions of glandular epithelial cells on the 20th day of life, reaching a maximum intensity on the 28th day and thus before the rats reached maturity. The results obtained allow the conclusion to be drawn that nitric oxide resulting from bNOS-activity participates in the processes of differentiation and of function in the epididymis, seminal vesicle and ventral prostate

Morphometric studies on rat testes in the course of postnatal development

Computer-assisted analysis of histologic images of rat testis in the course of postnatal period demonstrated its stepwise development. Three stages of the development could be distinguished, associated with different number of Leydig cells and with distinct secretive activity of the cell, as reflected by serum testosterone levels

The predicting role of substance P in the neoplastic transformation of the hypoplastic bone marrow

AIMS: To estimate the expression of substance P in the haematopoietic cells of hypoplastic bone marrow and define its relationship with the course of bone marrow hypoplasia. METHODS: Bone marrow specimens were obtained from 42 children with bone marrow hypoplasia who were hospitalised in the Department of Pediatric Oncology, Hematology and Transplantology, Poznan University of Medical Sciences, Poznan, Poland, between 1996 and 2003. Substance P and Ki‐67 expression were evaluated using immunochemical and hybridocytochemical assays. RESULTS: The expression of substance P (as evidenced by both immunocytochemical and hybridisation techniques) was confirmed in the cytoplasm of B lymphocytes in 8 of 11 children who developed acute leukaemia in 45 (SD 12) days. The percentage of substance P‐positive cells ranged from 67.6 to 95.8 (mean of 81.5% cells with immunocytochemistry and 84.3% with in situ hybridisation). The risk of development of leukaemia secondary to bone marrow hypoplasia was found to be significant (p<0.001) in those children who expressed substance P in normal‐looking lymphocytes at the initial bone marrow evaluation. CONCLUSIONS: The presence of substance P in B lymphocytes of hypoplastic bone marrow may predict its neoplastic transformation. A marked correlation between substance P‐positive bone marrow pattern and the expansion of tumour cells may prove the potential value of this oligopeptide in the pathogenesis of leukaemia

Pneumadin in the rat ventral prostate and its hormonal regulation

Pneumadin (PNM) is a decapeptide originally isolated from mammalian lungs, and exerts a potent antidiuretic action by stimulating arginine-vasopressin release. We have recently developed a sensitive and specific radioimmunoassay (RIA) for rat PNM and detected high concentrations of PNM--not only in the rat lungs, but also in the prostate. Hence, we investigated whether prostate PNM content is regulated by sex hormones. Male adult rats were orchidectomized or sham-operated and given a subcutaneous injection of testosterone or estradiol (40 and 5 mg/kg), respectively. The animals were decapitated one week after surgery, and their ventral prostates were promptly removed and weighed. PNM concentration and localization in the prostate were investigated by RIA and immunocytochemistry (ICC). Orchidectomy resulted in significant decreases in the prostate weight and PNM concentration, and testosterone administration prevented these effects. Estradiol administration to sham-operated rats caused prostate atrophy without changing PNM concentration. ICC localized PNM immunoreactivity (IR) exclusively in the epithelial cells of the ventral prostate. Orchidectomy markedly reduced PNM-IR concentration, while testosterone abolished this effect. Estradiol did not modify PNM-IR concentration in the atrophic prostate of sham-operated rats. We conclude that PNM content of rat prostate is dependent on the presence of adequate levels of circulating testosterone. The possibility that PNM plays a key role in the maintenance of the prostate growth is unlikely since estradiol-induced gland atrophy is not associated with any decrease in PNM concentration. The localization of PNM in the epithelial cells could suggest that this peptide may be involved in the regulation of some testosterone-dependent secretory functions of the rat prostate

Tissue distribution of pneumadin immunoreactivity in the rat

Pneumadin (PNM) is a decapeptide, originally isolated from mammalian lungs, which exerts a potent stimulating effect on arginine-vasopressin (AVP) release, thereby evoking an antidiuretic effect. We have established a specific radioimmunoassay (RIA) method for rat PNM determination, the sensitivity of which is sufficient for measuring tissue content of the peptide. Moreover, raised antibodies have been used for the immunocytochemical detection of PNM in several rat organs. As expected, high concentrations of PNM were detected by RIA in newborn and adult rat lungs and immunocytochemistry (ICC) localized PNM immunoreactivity (IR) in the bronchial and bronchiolar epithelium. Very high concentrations of PNM were measured by RIA in the prostate, and ICC showed that PNM-IR is contained in the epithelial cells. RIA and ICC demonstrated the presence of low amounts of PNM in the thymus. The highest content of radioimmunoassayable PNM was found in the kidneys and intestinal tract, but dilution test suggested the presence of some interfering substances in these tissues. Accordingly, ICC-detectable PNM-IR was absent in the kidneys and present only in the duodenal criptae and Brunner's glands of the intestinal tract. RIA did not measure sizeable PNM concentrations in the thyroid gland, but ICC showed PNM-IR in C-cells. RIA and ICC did not detected PNM in testes, seminal vesicles, ovaries, uterus, pancreas, liver, spleen, adrenal glands, and heart. Taken together, our findings suggest that PNM, in addition to its role as hypothalamo-pituitary AVP secretagogue, may be involved in the autocrine-paracrine functional regulation of other peripheral organs, like lungs and prostate and perhaps duodenum, thymus and thyroid gland

Pneumadin in the ventral prostate of rats during postnatal development: a radioimmunological and immunocytochemical study

We have recently demonstrated that the ventral prostate of adult rats contains high levels of pneumadin (PNM), a decapeptide originally isolated from mammalian lung, and that testosterone is needed for the maintenance of a normal level of the peptide in the prostate. Hence, we have investigated, by radioimmunoassay (RIA) and light ultrastructural immunocytochemistry (ICC), PNM concentration and localization in the rat ventral prostate during postnatal development. RIA showed that PNM content increased steadily from day 20 to day 90 of postnatal life, parallel to the increase in the prostate weight. In contrast, PNM concentration remained rather stable, although it showed a marked rise at day 40 when rat testes are known to reach their full maturation. ICC demonstrated that PNM immunoreactivity was mainly located in the apical pole of epithelial cells of rat ventral prostate, especially in the subcellular organelles involved in protein secretion, i.e. rough endoplasmic reticulum cisternae, vacuoles and granules. Taken together our study suggests the involvement of PNM in the functional control of rat prostate during postnatal maturation, although its exact role remains to be elucidated