Banding patterns of human chromosomes obtained with various new techniques-quinacrine mustard staining, staining after heating, and staining after proteolytic digestion —are compared. Depending on the technique, the same band may be stained or not, but the sequence of the bands is identical with all techniques.
Hybridization between a mouse Leydig tumor cell line, MA-10, which produces cyclic AMP and progesterone under human chorionic gonadotropin (hCG) stimulation, and freshly isolated mouse Leydig cells gave rise to 54 hybrid clones, one of which, LK17, was capable of hCG-stimulated testosterone production. Subcloning of this hybrid resulted in the emergence of a subclone, K9, whose testosterone production is more than 10 times that of parent clone LK17, after hCG stimulation, with an ED50 of 37 pM. Testosterone synthesis by K9 cells was multiplied by 25 after gonadotropin stimulation, and binding of hCG declined after prolonged exposure to the hormone. These similarities with murine Leydig cells in primary culture make the K9 clone an attractive alternative for physiological studies.
A method for the purification of epithelial cells from the three anatomical regions of the rat epididymis (corpus, caput and cauda) is described. An enzymic digestion followed by sedimentation of crude cell suspension on discontinuous Percoll gradient yielded quite pure active epithelial cell population as judged by morphological and functional studies. Electron microscopy analysis showed that cells from bands corresponding to densities 1.055 and 1.06 g/ml the gradient preserved a morphology compatible with their epithelial origin and their absorptive and secretory functions. Moreover, they stained positively with anticytokeratin antibody (95-97%) and were negative for antidesmin antibody. They selectively bound L-carnitine through a time-dependent and saturable system and differences in the rate of binding were apparent according to the three anatomical regions of the epididymis.
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