Some biochemical characteristics of hormone-secreting pituitary tumors and of the host's anterior pituitary gland.
The activity of some glycolytic, oxidative, and degradative enzymes was studied in transplanted rat hormone-secreting pituitary tumors MtTW15 and 7315a and in the host pituitary gland. The elevated serum-hormone concentrations produced by 7315a tumor decreased the size of the host's pituitary gland, its hormone content, and G6P-DH, LDH, PK, and ICDH, but produced no changes in MDH, acid phosphatase, cathepsin-D, and LYSAR enzyme activities (mU/mg tissue). LDH and PK activities were greater in unit weight of pituitary tumors than in pituitary glands. Although more G6P-DH was found in MtTW15 tumor than in normal pituitary tissue, less of the enzyme was detected in 7315a pituitary tumor. It is concluded that elevated serum pituitary hormones selectively decrease hormone production and the activity of some enzymes in the pituitary gland, presumably through a feedback mechanism.
D000818:Animals; D005260:Female; D006019:Glycolysis; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D009374:Neoplasms, Experimental / Q000378:metabolism / Q000503:physiopathology; D010447:Peptide Hydrolases / Q000378:metabolism; D010903:Pituitary Gland, Anterior / Q000378:metabolism / Q000503:physiopathology*; D010911:Pituitary Neoplasms / Q000378:metabolism / Q000503:physiopathology*; D011388:Prolactin / Q000097:blood; D051381:Rats
D009243:NAD; D009249:NADP; D011388:Prolactin; D010447:Peptide Hydrolases