Gonadotropic Hormone Release from Fetal and Adult Rat Pituitary Glands after in vitro Exposure to Synthetic LH-FSH-RH

1974 ◽  
Vol 16 (5-6) ◽  
pp. 332-341 ◽  
Author(s):  
S.J. Schafer ◽  
W.H. McShan
Keyword(s):  
Hormone Release ◽  
Gonadotropic Hormone ◽  
Adult Rat ◽  
Rat Pituitary ◽  
Pituitary Glands

Expression of Ptx1 in the adult rat pituitary glands and pituitary cell lines: hormone-secreting cells and folliculo-stellate cells

1999 ◽  
Vol 298 (1) ◽  
pp. 55-61 ◽  
Author(s):  
Reiko Kurotani ◽  
Shigeyuki Tahara ◽  
Naoko Sanno ◽  
Akira Teramoto ◽  
Pamela L. Mellon ◽  
...  
Keyword(s):  
Cell Lines ◽  
Stellate Cells ◽  
Pituitary Cell ◽  
Adult Rat ◽  
Rat Pituitary ◽  
Pituitary Glands

BIOSYNTHESIS OF GONADOTROPHINS BY RAT PITUITARIES IN VITRO

1975 ◽  
Vol 66 (3) ◽  
pp. 369-374 ◽  
Author(s):  
MRIDULA CHOWDHURY ◽  
EMIL STEINBERGER
Keyword(s):  
Comparative Study ◽  
Anterior Pituitary ◽  
Male Rats ◽  
Leucine Incorporation ◽  
Experimental Conditions ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Endogenous Proteases ◽  
Pituitary Homogenate

SUMMARY A method has been developed for studying biosynthesis of FSH in the rat pituitary in vitro. Anterior pituitary glands were incubated with [3H]leucine; a specific and sensitive immunoprecipitation technique was used to isolate FSH from the pituitary homogenate. Total FSH content of the samples was measured by a double-antibody radioimmunoassay technique. Using this technique, a comparative study of LH and FSH synthesis in the same pituitary of adult male rats incubated for various intervals (0·5–6 h) was done. Increased incorporation of [3H]leucine into both LH and FSH with time was noted. The rate and amount of [3H]leucine incorporation into FSH was found to be higher than that into LH, indicating that either the rate of FSH synthesis is higher than that of LH or FSH has more leucine residues than LH. Greater susceptibility of LH to degradation by endogenous proteases during dialysis may also reflect less incorporation of [3H]leucine into LH. This method provides a reliable tool for evaluating FSH synthesis under various experimental conditions.

INFLUENCE OF STEROID SEX HORMONES ON THE F. S. H.-RELEASE BY RAT HYPOPHYSES IN VITRO

1961 ◽  
Vol 36 (4) ◽  
pp. 485-497 ◽  
Author(s):  
G. P. van Rees
Keyword(s):  
Sex Hormones ◽  
Female Rats ◽  
Male Rats ◽  
Intact Female ◽  
Intact Male ◽  
Incubation Experiments ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Steroid Sex Hormones

ABSTRACT The hypothesis that steroid sex hormones influence pituitary F. S. H. by independent actions on its production and capacity of the gland to release it has been investigated by means of incubation experiments. During incubation, rat pituitary glands released considerable amounts of F. S. H. into the medium. Inactivation of F. S. H. during incubation could not be demonstrated; once (in females) some production of F. S. H. was even observed. The amount of F. S. H. which is released into the medium is influenced by the quantity of F. S. H. stored in the hypophyses. Hypophyses from male rats pretreated with oestradiol released relatively more F. S. H. into the medium than hypophyses from control animals. On the other hand, pretreatment with testosterone caused the pituitary glands to release less F. S. H. into the medium. In agreement with these results, hypophyses from intact male rats released relatively less F. S. H. than hypophyses from intact female rats. These facts support the hypothesis that androgens depress pituitary F. S. H.-secretion by inhibiting the capacity to release it, while oestrogens, which can even promote this property of the pituitary gland, also act by directly inhibiting its production.

LH-RH-dependent synthesis of protein necessary for LH release from rat pituitary glands in vitro

1976 ◽  
Vol 5 (1-2) ◽  
pp. 151-160 ◽  
Author(s):  
J. De Koning ◽  
J.A.M.J. Van Dieten ◽  
G.P. Van Rees
Keyword(s):  
Rat Pituitary ◽  
Pituitary Glands ◽  
Lh Release ◽  
Lh Rh

Cyproheptadine and desmethylcyproheptadine directly inhibit the release of adrenocorticotrophin and β-lipotrophin/β-endorphin activity from the neurointermediate lobe of the rat pituitary gland

1983 ◽  
Vol 96 (3) ◽  
pp. 395-400 ◽  
Author(s):  
S. W. J. Lamberts ◽  
E. G. Bons ◽  
P. Uitterlinden ◽  
W. H. Hackeng
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Serotonin Receptor ◽  
Direct Action ◽  
Anterior Pituitary Gland ◽  
Hormone Release ◽  
Neurointermediate Lobe ◽  
Rat Pituitary

Cyproheptadine and its metabolite desmethylcyproheptadine were shown to suppress directly the release of adrenocorticotrophin (ACTH) and β-lipotrophin/β-endorphin activity from the neurointermediate lobe of the pituitary gland incubated in vitro. Neither compound affected the release of ACTH from the anterior pituitary gland. Serotonin stimulated the release of ACTH and β-lipotrophin/β-endorphin activity from the neurointermediate lobe, but did not influence the (desmethyl)cyproheptadine-mediated inhibition of hormone release. These results indicate that serotonin and cyproheptadine affect hormone release by the neurointermediate lobe by a direct action. The effect of cyproheptadine, however, might not be exerted by a serotonin receptor.

Hypothalamic dopamine and catechol oestrogens in rats with spontaneous pituitary tumours

1983 ◽  
Vol 96 (2) ◽  
pp. 347-352 ◽  
Author(s):  
R. A. Prysor-Jones ◽  
J. J. Silverlight ◽  
J. S. Jenkins
Keyword(s):  
Pituitary Gland ◽  
Plasma Prolactin ◽  
Pituitary Tumours ◽  
Dopamine Concentration ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Normal Rat ◽  
Old Rats ◽  
Hypothalamic Dopamine

Dopamine concentration within the hypothalamus and its depletion after the administration of α-methyl-para-tyrosine were measured in young rats and compared with values obtained in aged animals with and without spontaneously occurring pituitary tumours. Old rats had significantly reduced hypothalamic dopamine concentrations and there was less depletion of dopamine compared with young animals but there were no differences between tumorous and non-tumorous animals. Hyperprolactinaemia induced in young animals caused a much greater depletion of hypothalamic dopamine than in old tumorous rats with comparable plasma prolactin concentrations. The catechol oestrogen 2-hydroxyoestradiol inhibited the release of prolactin from normal rat pituitary glands in vitro but measurement of catechol oestrogens in the hypothalamus showed no differences between young and old tumorous or non-tumorous rats. It is concluded that reduced dopamine concentration and an impaired response to hyperprolactinaemia in old rats may facilitate the growth of prolactin-secreting tumours arising in the pituitary gland.

ETUDE DE L'ACTION DU FACTEUR HYPOTHALAMIQUE LRF (LH-RELEASING FACTOR) CHEZ LE RAT IN VIVO & IN VITRO

1967 ◽  
Vol 55 (3) ◽  
pp. 481-496 ◽  
Author(s):  
Marian Jutisz ◽  
Annette Bérault ◽  
Marie-Anne Novella ◽  
Geneviève Ribot
Keyword(s):  
Dose Response ◽  
Crude Extract ◽  
Response Curve ◽  
Assay Method ◽  
Hypothalamic Extract ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Releasing Effect

ABSTRACT A highly purified ovine LH-releasing factor (LRF) was obtained by a modification of the method previously described. After the fractionation of a crude hypothalamic extract on a Sephadex G-25 column, the LRF fraction was desalted and partially purified by chromatography on a Dowex 50 × 12 column and on an Amberlite CG 4B column. The last step of this method, chromatography on a CMC column, gave a purification of about 1600 times with respect to the crude extract. The action of this highly purified LRF preparation was studied on rat pituitary glands in vivo and in vitro. The method used in vivo was the evaluation of the LH-releasing effect of LRF in chronically ovariectomized, steroid-blocked rats (Ramirez & McCann 1963 b). A procedure was developed which allows a 4-fold concentration of the plasma LH from these rats, so that it can be assayed by a 4-point assay method. In the in vitro method, the pituitary glands of ovariectomized steroidblocked rats (Schally & Bowers 1964 a) were incubated in a Krebs-Ringer buffer with or without LRF, and the LH released into the medium was assayed using the O.A. A.D. method of Parlow. A dose-response curve was established between the log doses of LRF and the amount of LH released. This method can be used as a sensitive and specific assay for LRF. It was shown that a dose of 1.22 μg of LRF releases approximately 5 μg of LH per mg of pituitary tissue. This is about double of the amount of this hormone originally present in the pituitary glands of these rats (2.7 μg/mg). This leads us to the conclusion that the excess of this hormone was probably synthetized during the process of incubation. The amount of steroids injected as a blocking agents, appears to be very important for both in vivo and in vitro tests.

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