A turnover study in the male rat of plasma-bound 59Fe, 114Inm and 109Cd with particular reference to the gonad

Cadmium accumulation and binding characteristics in intact Sertoli/germ cell units, and associated effects on stage-specific functionsin vitro: insights from a shark testis model

The increased human use of cadmium (Cd) and its increased occurrence in the environment is of concern. The testis is sensitive to Cd because of the steroid-mediated regulation of spermatogenesis, high levels of DNA synthesis and gene transcription, all of which varies in a stage-related manner. Validated techniques (acridine orange vital staining to detect apoptosis and dextran-rhodamine exclusion to assess blood-testis barrier function) were recently developed and the shark testis was proposed as an alternative model for assessing stage-specific functions in living testicular tissue and to study toxicant actions on spermatogenesis. The present paper shows that 109Cd accumulation and binding in vitro was stage-dependent (premeiotic, PrM > meiotic, M > postmeiotic, PoM), rapid and persisted in spermatocysts (intact germ cell/Sertoli cell units) 49 h after washout. In competitive binding analyses of all three spermatocyst stages, Hg, but not Zn, could replace bound 109Cd, suggesting that Cd binding was specific. These findings were associated with a biphasic apoptotic response in the PrM spermatocysts, which was maximal at 10 microm CdCl2 and 1 microm CdCl2 after 2 and 4 days in culture, respectively. Although Cd uptake in PoM cysts was more than 2-fold less than uptake in PrM cysts, the percentage dextran-rhodamine permeant PoM cysts was approximately 8-fold greater than in controls in the presence of both 10 microm CdCl2 and 30 microm CdCl2 after 4 days culture, indicating that blood-testis barrier function in PoM spermatocysts was compromised. These findings demonstrate that this model has utility for use in screening assays of environmental toxicants.

Spleen-targeted 114In(m) via normal and heat-damaged red cells in the mouse: isotope distribution and bone marrow damage

114In(m)-labelled heat-damaged erythrocytes (HDRBC) in BDF1 mice were quantitatively much less successful in spleen targeting than in the rat. Unheated labelled cells (NRBC) were an even less effective vector. Radiobiological effects manifest in the spleen (weight loss) and white cell count were nevertheless substantial, comparable in both groups and unchanged after 14 days. Considerable early renal loss of indium is inferred in the NRBC animals, but in the HDRBC group a high proportion was retained in the liver. Progenitor cell marrow cultures indicated acute transitory lethal effects with only partial recovery at termination; the marrow concentration of indium was the same in both groups.