Sertoli cell modulates MAA-induced apoptosis of germ cells throughout voltage-operated calcium channels

Spontaneous cell death by apoptosis--occurring during normal spermatogenesis in mammals--is a prominent event, which results in the loss of up to 75% of the potential number of mature spermatozoa. In the rat testis, the most conspicuous dying cells are pachytene spermatocytes, which are also the primary target of the apoptosis experimentally induced by methoxyacetic acid (MAA). In this paper, we have used clusterin expression as an indicator of germ cell apoptosis in rat seminiferous tubules treated with MAA in the presence or in the absence of voltage-operated calcium channels (VOCCs) inhibitors. We performed both a qualitative analysis of clusterin expression by immunofluorescence experiments and a quantitative analysis of apoptosis by in situ end labeling of apoptotic germ cells followed by flow cytometry. The results obtained demonstrate that Sertoli cells, the somatic component of the seminiferous epithelium, which control male germ cell differentiation, also modulate MAA-induced apoptosis of germ cells throughout voltage-operated calcium channels

Labeling of phospholipids in vesicles and human-erythrocytes by photoactivable fatty-acid derivatives

The photoactivable glycolipid probes, 2-(4-azido-2-nitrophenoxy)palmitoyl[1-I4C]glucosamine (compound A) and 12-(4-azido-2-nitrophenoxy)stearoyl[1-14C]glucosamine (compound B) were synthesized essentially as described before [Iwata, K. K. et al. (1978) Prog. Clin. Biol. Res. 22, 579–589]. These probes were used to label phospholipid vesicles and erythrocyte membranes. A chromatographic method was developed to quantify the individual probe-phospholipid adducts involving both phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine. For both membranes as well as for both probes a phospholipid labeling pattern was obtained which appeared to reflect the relative content of fatty acid double bonds in each phospholipid class. The distinct labeling of phosphatidylserine in intact erythrocytes strongly suggested that the probes spontaneously and rapidly redistributed between the two halves of the membrane bilayer. In addition, both probes yielded an extensive labeling of the membrane proteins. Analysis by dodecylsulfate-polyacrylamide gel electrophoresis and autoradiography has indicated that the protein labeling pattern was different, depending on whether the ‘shallow’ probe (compound A) or ‘depth’ probe (compound B) were usedPeer reviewe