Biomedical subjects
Publications and source records attributed to M Galdieri.
Explore the source record for details and available documents.
Sertoli cells were cultured alone or with germ cells to evaluate the effect of the association with germ cells on the secretory activity of Sertoli cells. Secretion of androgen-binding protein, which is specifically secreted by Sertoli cells, was measured under several experimental conditions. The following experimental models were utilized: 1) cultures of explants of seminiferous epithelium from prepubertal animals in which germ cells adherent to Sertoli cells are present (Sertoli cell enriched cultures); 2) monolayers formed only by Sertoli cells, obtained by removing germ cells from Sertoli cell enriched cultures, and 3) cocultures of Sertoli cell only cultures and germ cell populations at defined stages of differentiation. The results obtained indicated that FSH-induced ABP secretion was greatly reduced in Sertoli cell only cultures as compared to enriched Sertoli cell cultures, and that this difference was stable throughout the first eight days of culture. In addition, cocultures of Sertoli cell only cultures with germ cells induced an increase of ABP when cocultured germ cells were at differentiation stages, such as pachytene spermatocytes, which are able to recognize and firmly adhere to the Sertoli cell monolayers. Cocultures with round spermatids, which do not adhere to Sertoli cells, did not increase the amount of FSH-induced ABP production. The addition of nongerminal cells such as lymphocytes and fibroblasts were also not effective in stimulating ABP secretion. Surface interaction between Sertoli cells and cocultured germ cells seemed to be necessary for this FSH-induced ABP production.(ABSTRACT TRUNCATED AT 250 WORDS)
Sertoli cells obtained from prepubertal rat testes were cultured in the presence or absence of retinol. Incorporation of monosaccharides and glycopeptide composition of the cells were studied under two experimental conditions. The results indicate that retinol increases the amount of mannose and glucosamine incorporated into cellular glycoconjugates. The labeled glycopeptides obtained from control and retinol-treated cells were separated by size and lectin affinity. Gel filtration analysis showed no size differences between the glycopeptides obtained from control and vitamin A-treated cells. Affinity chromatography on Concanavalin A and Wheat Germ Agglutinin of 3H-mannose-labeled glycopeptides showed that Sertoli cells cultured in the presence of retinol contain a higher percentage of high mannose-type glycopeptides compared with control cells. The effect of retinol on Sertoli cell glycopeptide composition is partially reversed by the administration of FSH.
Explore the source record for details and available documents.
Mammalian spermatozoa acquire motility and fertilizing capacity during their transit through the epididymis. Hepatocyte growth factor (HGF) is a pleiotropic cytokine with potent motogenic capacities that has been identified in different organs, including the mammalian male genital tract. In mice, HGF is present in the testis and, in large amounts, in the distal part of the epididymis. In prepuberal rats, we have demonstrated that HGF is synthesized by the peritubular myoid cells and in men, HGF is present in significant quantities in seminal plasma. It has been suggested that in mice, HGF has a role in initiating sperm motility, whereas in men, no significant correlations between HGF concentration and sperm motility have been found. In the present paper we report that in rats, HGF receptor, c-met, is expressed in testicular and epididymal spermatozoa. Through immunocytochemistry, we have found that c-met is exclusively localized on the head in testicular sperm. A different localization of c-met has been found in sperm isolated from caput and cauda epididymidis. Cells isolated from epididymal caput show a c-met localization exclusively restricted to the head in most cells. In a minority of caput epididymis spermatozoa the receptor is localized both in the cell head and along the flagellum. Spermatozoa isolated from the epididymal cauda were quite homogeneous, showing the receptor localized along the entire cell surface. We also report that HGF is synthesized and secreted by the rat epididymis as indicated by the scatter effect of epididymal cell homogenate and culture medium on MDCK cells. To clarify whether HGF is involved in the acquisition of sperm motility in the epididymis, its maintenance, or both, spermatozoa isolated from caput epididymidis have been cultured in medium alone or supplemented with HGF. The results obtained indicated that HGF has a positive effect on the maintenance of sperm motility which, in the absence of HGF, significantly decreases during the first hour of culture, whereas it is maintained for at least 3 hours when HGF is present in the culture medium. We also report that HGF does not influence spermatozoa viability as indicated by the cytometrical analysis of propidium iodide-labeled sperm; an equal number of dead cells appeared in control and in HGF-treated preparations. In conclusion, our data strongly support the hypothesis that HGF positively influences sperm motility maintenance during sperm transit through the epididymis, indicating that c-met receptor and its ligand, HGF, have a role in male fertility.
Explore the source record for details and available documents.