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PROTEIN AND PEPTIDE HYDROLASES OF THE RAT HYPOTHALAMUS AND PITUITARY
Author(s) -
Marks N.,
Galoyan A.,
Grynbaum Alice,
Lajtha A.
Publication year - 1974
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1974.tb04288.x
Subject(s) - tripeptide , peptide , hypothalamus , enzyme , hormone , posterior pituitary , peptide hormone , biochemistry , chemistry , medicine , endocrinology , amino acid , biology , pituitary gland
Peptide and peptidyl‐peptide hydrolase activities were measured in the cerebral cortex, adenoand neurohypophysis, anterior and posterior regions of the hypothalamus to assess regional differences in peptide hormone turnover. In general all enzyme activities were higher in the pituitary except for the monoacyl arylamidase which was lower, and neutral proteinase which was distributed more evenly in all regions. Of the enzymes measured the highest activities occurred in the presence of the di‐ and tripeptide substrates (aminopeptidases); this activity was some 20‐60‐fold higher than the acid and neutral proteinases. Comparison of the peptide‐amide substrates revealed the highest activity with the monoacyl derivative which was five‐fold higher than the dipeptidyl, and 50‐fold higher than the tripeptidyl (hormonal) factor Pro‐Leu‐Gly. NH 2 . Analysis of the breakdown products of the hormonal factor indicated inactivation by N‐terminal release of Pro, Leu with Gly. NH 2 as the final product. Regional differences in enzyme content in neurosecretory areas suggest that this plays a role in the turnover of specific hormones.