Immunocytochemical localization of cathepsins B and H in corticotrophs and melanotrophs of rat pituitary glandY Uchiyama, M Nakajima, D Muno, T Watanabe, Y Ishii, S Waguri, N Sato and E Kominami Department of Anatomy, University of Tsukuba, Ibaraki-Ken, Japan. We examined by immunocytochemistry the localization of cathepsins B and H in corticotrophs and melanotrophs in anterior and intermediate lobes of rat pituitary gland, using monospecific antibodies to cathepsins B and H. In serial semithin sections, immunodeposits for cathepsin H were detected throughout the cytoplasm of cells immunoreactive for ACTH and alpha-MSH in anterior and intermediate pituitary. Granular immunodeposits for cathepsin B were demonstrated in anterior and intermediate cells. Double immunostaining colocalized immunogold particles for cathepsin H and ACTH or alpha-MSH in secretory granules of corticotrophs or melanotrophs, whereas those for cathepsin B were detected only in their lysosomes. Enzyme assay demonstrated cathepsin B activity in both anterior and intermediate pituitary tissue, but did not detect cathepsin H activity in the intermediate pituitary. Western blotting, however, revealed the presence of cathepsin H and cystatin beta in intermediate pituitary. These results suggest that cathepsin B plays a role in protein degradation in lysosomes of corticotrophs and melanotrophs. Moreover, the presence of cathepsin H in secretory granules of the cells may indicate that the enzyme participates in the activation of secretory products.
Volume 38,
Issue 5,
pp. 633-639,
05/01/1990
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V. Claus, A. Jahraus, T. Tjelle, T. Berg, H. Kirschke, H. Faulstich, and G. Griffiths Lysosomal Enzyme Trafficking between Phagosomes, Endosomes, and Lysosomes in J774 Macrophages. ENRICHMENT OF CATHEPSIN H IN EARLY ENDOSOMES J. Biol. Chem., April 17, 1998; 273(16): 9842 - 9851. [Abstract] [Full Text] [PDF] |
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