The effects of gonadotropin-releasing hormone and estradiol on luteinizing hormone biosynthesis in cultured rat anterior pituitary cells.

@article{Ramey1987TheEO,
  title={The effects of gonadotropin-releasing hormone and estradiol on luteinizing hormone biosynthesis in cultured rat anterior pituitary cells.},
  author={J. W. Ramey and Robert F. Highsmith and William W Wilfinger and David M. Baldwin},
  journal={Endocrinology},
  year={1987},
  volume={120 4},
  pages={
          1503-13
        }
}
This study investigated the effects of physiological concentrations of GnRH and estradiol (E2) on LH biosynthesis and release using cultured anterior pituitary cells. Pituitaries from female rats were enzymatically dispersed and cultured for 48 h in steroid-free alpha-Modified Eagle's Medium, followed by a 24-h culture in medium with or without E2. The cells were then incubated for a 4-h (Exp 1 and 2) or 8-h (Exp 3) period in medium containing radiolabeled precursors with or without GnRH… Expand
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The data indicate that T acts directly at the pituitary to inhibit LH subunit apoprotein synthesis and selectively inhibit LH alpha glycosylation, and support the hypothesis that changes in LH gly cosylation may be one of the ways by which GnRH and T regulate LH release. Expand
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The results show that the steroid hormones exert opposite effects on the release of LH induced by GnRH, which seems to be dependent upon the length of time the pituitary cells have been exposed to the steroids. Expand
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GnRH-stimulated LH glycosylation and LH translation involve calcium-dependent mechanisms, and the results suggest that the release of newly synthesized LH is regulated differently from previously synthesized stored hormone. Expand
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It is concluded that GnRH stimulation of LH glycosylation and LH apoprotein synthesis involves extracellular calcium-dependent events, and the release of newly synthesized LH is closely coupled to LH biosynthesis and is less dependent on extrace cellular calcium, whereas the GnRH-stimulated release of previously synthesized, stored LH is dependent on external calcium. Expand
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Modulatory actions of estradiol and progesterone on phorbol ester-stimulated LH secretion from cultured rat pituitary cells
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Gonadal steroid modulation of signal transduction and luteinizing hormone release in cultured chicken pituitary cells.
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The mechanism whereby gonadal steroids modulate GnRH-stimulated LH secretion by primary cultures of chicken pituitary cells was investigated and it is suggested that the site of steroid modulation of GnRH action is distal to binding of Gn RH to its receptor, and that the inhibitory effects are exerted at two intracellular sites. Expand
Detection of a lag phase in gonadotropin-releasing hormone stimulated synthesis of lutropin peptide chains in cultured rat anterior pituitary cells.
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References

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Effect of in vivo treatment with estrogen on luteinizing hormone synthesis and release by rat pituitaries in vitro.
TLDR
The results suggest that estrogen and GnRH regulate LH synthesis at different sites, and that the effect of estrogen is non-specific compared to that of GnRH. Expand
Biphasic effects of estrogen on gonadotropin-releasing hormone-induced luteinizing hormone release in monolayer cultures of rat and monkey pituitary cells.
TLDR
The results demonstrate that estradiol exerts a potent but transient inhibition of GnRH-induced LH release in monolayer cultures of rat pituitary cells and indicate that cultured pituitaries are responsive to the biphasic actions of estradio and demonstrate the utility of two model systems for investigating these phenomena. Expand
Comparison of the biosynthesis and release of luteinizing hormone by rat pituitaries in vitro in response to gonadotropin-releasing hormone analogs.
In an attempt to determine whether gonadotropin-releasing hormone (GnRH) regulates synthesis and release of LH via independent processes, the ability of several GnRH analogs to regulate LH releaseExpand
The sensitizing effect of estrogens and catechol estrogen on cultured pituitary cells to luteinizing hormone-releasing hormone: its antagonism by progestins.
TLDR
The direct effect of steroid hormones upon LHRH-induced LH release was tested in cultured pituitary gonadotrophs and a dose-related increase in LH secretion was observed with increasing concentrations of L HRH. Expand
Effects of a low calcium environment on luteinizing hormone biosynthesis in cultured rat anterior pituitary cells.
TLDR
It is concluded that GnRH stimulation of LH glycosylation and LH apoprotein synthesis involves extracellular calcium-dependent events, and the release of newly synthesized LH is closely coupled to LH biosynthesis and is less dependent on extrace cellular calcium, whereas the GnRH-stimulated release of previously synthesized, stored LH is dependent on external calcium. Expand
Effects of estradiol on basal and luteinizing hormone releasing hormone (LHRH)-induced release of luteinizing hormone (LH) from bovine pituitary cells in culture.
TLDR
It is concluded that chronic exposure of bovine pituitary cells to E2 increased basal LH release and synthesis and acute exposure to 5, 50 or 500 ng E2 /ml media increased sensi- tivity of bova- tive cells to LU RH. Expand
Biosynthesis of gonadotropins by rat pituitary cells in culture and in pituitary homogenates: Effect of gonadotropin-releasing hormone
The incorporation of labeled amino acids and glucosamine into LH and FSH by cultured rat anterior pituitary cells and anterior pituitary homogenates is reported. There was a significant augmentationExpand
Estradiol-induced increase of the LH responsive to LH releasing hormone (LHRH) in rat anterior pituitary cells in culture.
TLDR
Data show clearly that E2 can have a direct stimulatory effect on LH-secreting cells to increase the sensitivity of their response to LHRH and that this effect is maximal after 24 h of incubation with the steroid. Expand
Synthesis and release of luteinizing hormone in vitro by rat anterior pituitary cells: effects of gallopamil hydrochloride (D600) and pimozide.
TLDR
The results demonstrate that D600 and pimozide inhibit both GnRH-induced LH glycosylation and release, which are both mediated by similar Ca2+-dependent pathways. Expand
Differential effects of cyclic nucleotide analogues and GnRH on LH synthesis and release.
TLDR
It appears that cAMP can mimic the action of GnRH on LH glycosylation, but may have little direct effect on LH release. Expand
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