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There have been few studies of physiological importance on the regulation of somatostatin by hormones. We have studied the effect of the synthetic glucocorticoid dexamethasone on somatostatin production in the human medullary thyroid carcinoma TT cell line, a model for somatostatin production by the parafollicular cell. Dexamethasone inhibited somatostatin production in a dose-related manner with a maximal effect at a concentration of 10(-6) M. TT cells treated with dexamethasone (10(-6) M) showed an almost complete inhibition of somatostatin peptide production by 48 h of treatment. Molecular sizing chromatography demonstrated a decrease in both the probable somatostatin precursor (13,000 dalton) and the fully processed peptide. Analysis of mRNA content by hybridization revealed that dexamethasone also caused a decrease in detectable somatostatin mRNA. The hybridizable somatostatin mRNA decreased to approximately 50% of basal levels within 12 h of treatment. Northern blot hybridization showed a decrease in a single RNA species representing mature somatostatin mRNA. Dose-response experiments revealed inhibition of both peptide and mRNA at concentrations from 1 X 10(-8) to 1 X 10(-5) M dexamethasone. Four days after withdrawal from dexamethasone treatment, peptide and mRNA levels were higher than dexamethasone-treated controls. The sex steroid estradiol had no inhibitory effect on somatostatin production. These results suggest a potential regulator of somatostatin production and provide a system for the study of somatostatin gene regulation.
G J Cote, and
W N Palmer, and
K Leonhart, and
S S Leong, and
R F Gagel
April 1986,
Endocrinology,
G J Cote, and
W N Palmer, and
K Leonhart, and
S S Leong, and
R F Gagel
August 1977,
The American journal of pathology,
G J Cote, and
W N Palmer, and
K Leonhart, and
S S Leong, and
R F Gagel
September 1996,
Nuclear medicine communications,
G J Cote, and
W N Palmer, and
K Leonhart, and
S S Leong, and
R F Gagel
April 1997,
The British journal of surgery,
G J Cote, and
W N Palmer, and
K Leonhart, and
S S Leong, and
R F Gagel
January 1994,
FEBS letters,
G J Cote, and
W N Palmer, and
K Leonhart, and
S S Leong, and
R F Gagel
May 1994,
Clinical nuclear medicine,
G J Cote, and
W N Palmer, and
K Leonhart, and
S S Leong, and
R F Gagel
February 1992,
Acta physiologica Scandinavica,
G J Cote, and
W N Palmer, and
K Leonhart, and
S S Leong, and
R F Gagel
October 2002,
Journal of endocrinological investigation,
G J Cote, and
W N Palmer, and
K Leonhart, and
S S Leong, and
R F Gagel
January 1987,
Peptides,
G J Cote, and
W N Palmer, and
K Leonhart, and
S S Leong, and
R F Gagel
January 1999,
Nuklearmedizin. Nuclear medicine,
