1,721,029 research outputs found
Role of the adenylate cyclase-cAMP system on TSH-stimulated thyroid cell growth
No full text: TSH is a trophic factor for cultured rat thyroid cells (FRTL-5). In the present study we have investigated the mechanism by which TSH promotes cell growth and evaluated the possible role of the adenylate cyclase (AC)-cAMP system in this process. The mitogenic activity of several agents was evaluated by measuring their effect on cell number or 3H-thymidine incorporation into DNA. Forskolin and cholera toxin, two potent and specific activators of the AC, induced a dose dependent increase of 3H-thymidine incorporation. The maximal stimulation, observed at concentrations of 10 microM and 10 ng/ml, respectively, was beta 80% of that obtained with optimal concentrations of TSH. A similar effect was obtained with a Graves' IgG preparation (0.2 mg/ml) able to stimulate the thyroid AC or with 3-isobutyl-1-methyl-xanthine (IBMX, 0.5 mM), a phosphodiesterase inhibitor. 8-bromo cAMP (0.5 mM), a cAMP analog, also stimulated 3H-thymidine incorporation, and its potency was approximately 60% of that of TSH. Similar results were obtained when the mitogenic activity of these compounds was evaluated by cell number. Norepinephrine (NE, 10 microM), although devoid of AC stimulatory activity in these cells, also stimulated 3H-thymidine incorporation, but its potency was only 20-30% of that of TSH. Indomethacin (100 microM), an inhibitor of phospholipid and arachidonic acid metabolism, was able to inhibit the stimulatory effect of NE (84%), and to a lesser extent of TSH (63%) and cholera toxin, had minor effect on forskolin (24%), IBMX (16%) and Graves' IgG (8%), and no effect on 8-bromo cAMP.(ABSTRACT TRUNCATED AT 250 WORDS
Increase of a follicular cell subset with a defined expression of family of integrins in multinodular goiter.
No full textThe expression of VLA family of integrins is associated with the proliferation in human thyroid follicular cells.
No full textAdhesion molecules expression in human follicular thyroid cells of normal and diseased glands.
No full text
Nelle cellule follicolari di tiroide in coltura la proliferazione si associa ad elevata espressione di alcune integrine.
No full text
Interference of thyroglobulin in TSAb detection by radio-receptor assay
No full textSir:
Dr.
Schleusener
et
al.
recently
reported
in
this
Journal
(1)
that
thyroid-stimulating
antibody
(TSAb)
determina-
tions
in
Graves'
patients
could
be
useful
in
predicting
relapse
after
antithyroid
drug
withdrawal.
TSAb
is
present
in
serum
of
many
untreated
Graves'
patients,
but
the
percent
of
positive
patients
differs
among
the
different
series
reported
(1-6).
These
dis-
crepancies
do
not
appear
justified
by
the
radio-
receptor
assay
methods
employed.
Human
thyroglobulin
(hTg)
is
found
in
serum
of
many
normal
subjects
in
an
average
concentration
of
about
5
ng/ml,
its
level
raises
up
to
>150
ng/
ml
in
untreated
Graves'
patients
(7),
decreases
with
antithyroid
drug
treatment
(8),
but
it
is
found
still
elevated
in
those
pa-
tients
who
relapse
after
drug
withdrawal
(8).
Recently
one
of
us
(9)
reported
that
physiological
amounts
of
thyroglobulin
can
interfere
in
the
binding
of
TSH
to
human
thyroid
plasma
membrane
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