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Parathyroid hormone induces transcription of collagenase in rat osteoblastic cells by a mechanism using cyclic adenosine 3',5'-monophosphate and requiring protein synthesisCollagenase is synthesized and secreted by rat osteoblastic cells in response to PTH. We have previously demonstrated that this effect involves a substantial increase in collagenase mRNA via transcription. Northern blots and nuclear run-on assays were performed to further investigate the induction of collagenase by PTH in the rat osteoblastic cell line UMR 106-01. Detectable amounts of collagenase mRNA were not apparent until 2 h of PTH treatment, showed the greatest abundance at 4 h, and declined to approximately 30% of maximum by 8 h. The changes in the rate of transcription of the collagenase gene in response to PTH paralleled and preceded the changes in the steady state mRNA levels. After an initial lag period of about 1 h, collagenase transcription rates increased from very low levels to a maximal response at 2 h, returning to about 50% of maximum by 10 h. The increased transcriptional rate of the collagenase gene was found to be dependent on the concentration of PTH, with a half-maximal response at approximately 7 x 10(-10) M rat PTH-(1-34) and a maximal effect with a dose of 10(-8) M. The PTH-mediated induction of collagenase transcriptional activity was completely abolished by cycloheximide, while transcription of the beta-actin gene was unaffected by the translation inhibitor. These data suggest that a protein factor(s) is required for PTH-mediated transcriptional induction of collagenase. Since PTH increases intracellular levels of several potential second messengers, agents that mimic these substances were employed to determine which signal transduction pathway is predominant in the PTH-mediated stimulation of collagenase transcription.(ABSTRACT TRUNCATED AT 250 WORDS).
Document ID
20050000560
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Scott, D. K.
(St. Louis University Medical Center Missouri 63104)
Brakenhoff, K. D.
Clohisy, J. C.
Quinn, C. O.
Partridge, N. C.
Date Acquired
August 22, 2013
Publication Date
December 1, 1992
Publication Information
Publication: Molecular endocrinology (Baltimore, Md.)
Volume: 6
Issue: 12
ISSN: 0888-8809
Subject Category
Life Sciences (General)
Funding Number(s)
CONTRACT_GRANT: AR-39743
CONTRACT_GRANT: T32-GM-08109
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Cell Biology
Non-NASA Center

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