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Glucocorticoids, triiodothyronine (T3), and cyclic adenosine monophosphate (cAMP) have been shown previously to modulate phosphatidylcholine and surfactant protein A (SP-A) synthesis in fetal rat lung explant cultures. In this report, we have examined the hormonal regulation of the rat surfactant protein B (SP-B) mRNA to determine whether SP-B expression is coordinately regulated with the surfactant phospholipids or with SP-A. Dexamethasone (1 to 200 nM) and cAMP (200 microM) had a stimulatory effect on SP-B mRNA levels, whereas T3 tended to inhibit the accumulation of SP-B mRNA. In combination experiments, treatment with dibutyryl-cAMP (200 microM) and dexamethasone (100 nM) resulted in about a 22-fold increase, whereas dexamethasone or dibutyryl-cAMP alone produced 18- and 2-fold increases, respectively. When the cAMP analogue 8-bromo-cAMP (200 microM) was used in combination with dexamethasone, there was no significant difference between the combined effect and that of dexamethasone alone. T3 treatment, however, resulted in a significant reduction of the dexamethasone-induced stimulation from about a 22-fold to a 14-fold increase. Tissue in situ hybridization showed that dexamethasone stimulated the levels of SP-B mRNA in cells from both the alveolar and bronchiolar epithelium. These data indicate that there are differences in the hormonal regulation of the components of surfactant, suggesting that they are independently regulated.
J Floros, and
I Gross, and
K V Nichols, and
S V Veletza, and
D Dynia, and
H W Lu, and
C M Wilson, and
S M Peterec
January 1998,
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J Floros, and
I Gross, and
K V Nichols, and
S V Veletza, and
D Dynia, and
H W Lu, and
C M Wilson, and
S M Peterec
November 1996,
The American journal of physiology,
J Floros, and
I Gross, and
K V Nichols, and
S V Veletza, and
D Dynia, and
H W Lu, and
C M Wilson, and
S M Peterec
January 1991,
Journal of developmental physiology,
J Floros, and
I Gross, and
K V Nichols, and
S V Veletza, and
D Dynia, and
H W Lu, and
C M Wilson, and
S M Peterec
November 1994,
The Journal of biological chemistry,
J Floros, and
I Gross, and
K V Nichols, and
S V Veletza, and
D Dynia, and
H W Lu, and
C M Wilson, and
S M Peterec
August 1988,
Journal of applied physiology (Bethesda, Md. : 1985),
J Floros, and
I Gross, and
K V Nichols, and
S V Veletza, and
D Dynia, and
H W Lu, and
C M Wilson, and
S M Peterec
July 1994,
The American journal of physiology,
J Floros, and
I Gross, and
K V Nichols, and
S V Veletza, and
D Dynia, and
H W Lu, and
C M Wilson, and
S M Peterec
September 1998,
The American journal of physiology,
J Floros, and
I Gross, and
K V Nichols, and
S V Veletza, and
D Dynia, and
H W Lu, and
C M Wilson, and
S M Peterec
January 1997,
Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc,
J Floros, and
I Gross, and
K V Nichols, and
S V Veletza, and
D Dynia, and
H W Lu, and
C M Wilson, and
S M Peterec
July 1993,
Science (New York, N.Y.),
J Floros, and
I Gross, and
K V Nichols, and
S V Veletza, and
D Dynia, and
H W Lu, and
C M Wilson, and
S M Peterec
September 1992,
American journal of respiratory cell and molecular biology,
