Sensitivity of rat adenohypophyseal cells to estradiol and LHRH during long-term culture

1981 ◽  
Vol 240 (6) ◽  
pp. E602-E608
Author(s):  
L. Lagace ◽  
F. Labrie ◽  
T. Antakly ◽  
G. Pelletier
Keyword(s):  
Luteinizing Hormone ◽  
Cell Types ◽  
Thyroid Stimulating Hormone ◽  
Time Interval ◽  
Pituitary Cells ◽  
Luteinizing Hormone Releasing Hormone ◽  
Lh Release ◽  
Lh Rh ◽  
Stimulating Hormone

To determine possible effects of the time in culture on the responsiveness of the different pituitary cell types to estrogens, rat anterior pituitary cells were incubated up to 20 days in the presence or absence of 10 nM 17 beta-estradiol. Whereas spontaneous luteinizing hormone (LH) and thyroid-stimulating hormone (TSH) release decreased by 85-90%, follicle-stimulating hormone (FSH) and prolactin accumulation in medium were only 50% decreased after 20 days in culture, thus suggesting that the secretion of FSH and prolactin is less dependent on extrinsic stimulatory factors. Estradiol increased spontaneous LH release and its responsiveness to luteinizing hormone-releasing hormone (LH-RH) up to day 16 in culture, whereas the stimulatory effect of the estrogen on FSH secretion was significant only up to day 6. The stimulatory effect of estradiol on basal TSH release was seen up to day 8 in culture, whereas that on spontaneous prolactin release increased progressively after day 8 in culture up to the last time interval studied (20 days). As revealed by immunocytochemistry, the stimulatory effect of estradiol was not due to changes of cell growth.

STIMULATION OF PROSTAGLANDIN ACCUMULATION IN THE RAT ANTERIOR PITUITARY GLAND BY LUTEINIZING HORMONE RELEASING HORMONE IN VITRO

1977 ◽  
Vol 75 (2) ◽  
pp. 277-283 ◽  
Author(s):  
N. BARDEN ◽  
A. BETTERIDGE
Keyword(s):  
Luteinizing Hormone ◽  
Cyclic Amp ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Lh Release ◽  
Lh Rh ◽  
Stimulation Of

The addition of luteinizing hormone releasing hormone (LH-RH) to cultures of monolayers of rat anterior pituitary cells was shown to increase both the concentrations of prostaglandins E1 and E2 (PGE) in the cells and the release of LH over similar ranges of concentrations of LH-RH (10−6 to 10−10 mol/l). The peak concentration of PGE was observed after 2·5 h. The stimulation of the level of PGE in the cells by LH-RH was completely inhibited by two inhibitors of prostaglandin synthetase, which only partially inhibited the stimulation of LH release. Therefore the increased concentration of PGE was not obligatory for the effect of LH-RH on LH release. It was also shown that monobutyryl cyclic AMP stimulated the intracellular concentration of PGE and it is suggested that the stimulation of PGE levels may be mediated by increased levels of cyclic AMP in the cells after the addition of LH-RH.

Melatonin inhibits luteinizing hormone releasing hormone (LHRH) induction of LH release from fetal rat pituitary cells

1995 ◽  
Vol 184 (2) ◽  
pp. 109-112 ◽  
Author(s):  
Atsuhiko Hattori ◽  
Damon C. Herbert ◽  
Mary K. Vaughan ◽  
Ken Yaga ◽  
Russel J. Reiter
Keyword(s):  
Luteinizing Hormone ◽  
Pituitary Cells ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Fetal Rat ◽  
Rat Pituitary ◽  
Lh Release ◽  
Rat Pituitary Cells

Stimulatory effect of thyrotrophin-releasing hormone (TRH) on the release of luteinizing hormone (LH) from rat anterior pituitary cells in vitro

1983 ◽  
Vol 61 (2) ◽  
pp. 186-189 ◽  
Author(s):  
Noboru Fujihara ◽  
Masataka Shiino
Keyword(s):  
Luteinizing Hormone ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Anterior Pituitary Cells ◽  
Lh Release ◽  
Lh Rh

The effect of thyrotrophin-releasing hormone (TRH, 10−7 M) on luteinizing hormone (LH) release from rat anterior pituitary cells was examined using organ and primary cell culture. The addition of TRH to the culture medium resulted in a slightly enhanced release of LH from the cultured pituitary tissues. However, the amount of LH release stimulated by TRH was not greater than that produced by luteinizing hormone – releasing hormone (LH–RH, 10−7 M). Actinomycin D (2 × 10−5 M) and cycloheximide (10−4 M) had an inhibitory effect on the action of TRH on LH release. The inability of TRH to elicit gonadotrophin release from the anterior pituitary glands in vivo may partly be due to physiological inhibition of its action by other hypothalamic factor(s).

EFFECTS OF DEXAMETHASONE ON THE RESPONSES OF LUTEINIZING HORMONE AND TESTOSTERONE TO TWO INJECTIONS OF LUTEINIZING HORMONE RELEASING HORMONE IN YOUNG POSTPUBERTAL BULLS

1978 ◽  
Vol 77 (3) ◽  
pp. 389-395 ◽  
Author(s):  
P. CHANTARAPRATEEP ◽  
M. THIBIER
Keyword(s):  
Luteinizing Hormone ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Site Of Action ◽  
Lh Release ◽  
Lh Rh

Six young postpubertal bulls were studied in two experiments, 3 months apart. In experiment 1, three bulls received i.m. injections of dexamethasone (20 mg) and 5 h later these animals plus three control bulls received i.m. injections of luteinizing hormone releasing hormone (LH-RH, 250 μg). In experiment 2, the controls from experiment 1 received dexamethasone and the treated animals from experiment 1 acted as controls for experiment 2. All bulls also received an i.m. injection of 250 μg LH-RH on day 2 of each experiment. The concentrations of LH and testosterone in samples of jugular blood were determined by radioimmunoassay. There were no significant differences in the patterns of testosterone and LH release between the two experiments. On day 1, the response of LH to LH-RH was significantly (P < 0·05) reduced by dexamethasone, but on day 2 values in the control and treated groups were similar although significantly (P<0·05) lower than values on day 1. The response of testosterone to LH-RH was not affected by dexamethasone. These results are discussed in terms of the site of action at which dexamethasone may act to depress the release of LH.

INHIBIN FROM CULTURES OF RAT SEMINIFEROUS TUBULES

1978 ◽  
Vol 78 (2) ◽  
pp. 217-224 ◽  
Author(s):  
L. W. EDDIE ◽  
H. W. G. BAKER ◽  
A. DULMANIS ◽  
R. E. HIGGINSON ◽  
B. HUDSON
Keyword(s):  
Luteinizing Hormone ◽  
Active Material ◽  
Gel Filtration ◽  
Seminiferous Tubules ◽  
Pituitary Cells ◽  
Basal Secretion ◽  
Luteinizing Hormone Releasing Hormone ◽  
Rat Pituitary ◽  
Rat Pituitary Cells ◽  
Lh Rh

SUMMARY Medium from cultures of mature rat seminiferous tubules contained a substance which suppressed, in a dose-related manner, the luteinizing hormone releasing hormone (LH-RH)-stimulated secretion of FSH by cultured rat pituitary cells. The secretion of LH was suppressed to a lesser extent and the basal secretion of both LH and FSH was inconsistently affected. Gel filtration on Sephadex G-100 did not fractionate the activity. The active material did not inhibit the secretion of TSH or destroy LH-RH and the activity was not due to testosterone or oestradiol in the medium. Control media from liver cultures were inactive. It is concluded that inhibin is present in media from cultures of rat seminiferous tubules.

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