Thyrotropin releasing hormone: Direct evidence for stimulation of prolactin production by pituitary cells in culture

Tashjian, Armen H.; Barowsky, N. J.; Jensen, Dorothy

doi:10.1016/0006-291x(71)90644-9

Cited by 458 publications

(120 citation statements)

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“…The concept of the specificity of the interaction between TRF and its target organ was questioned when Tashjian, Barowsky & Jensen (1971) Vale, Blackwell, Grant & Guillemin (1973) could only demonstrate a release of prolactin in response to TRF from cell cultures and half pituitaries from rats fed propylthiouracil.…”

Section: Administration Of Thyrotrophin-releasingfactormentioning

confidence: 99%

Prolactin Release in the Sheep

Ge¹,

Moseley²,

McNeilly³

1974

Reproduction

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The recent development of radioimmunoassay for prolactin has extended the depth and extent of studies of factors affecting prolactin levels in mammals and has permitted long-term studies to be made of changes in blood prolactin levels in individual animals. Although ovine prolactin has been widely studied in relation to its structure (Li, 1972) and biological activity (see Wolstenholme & Knight, 1972) and has been extensively used as a reference material, the serum prolactin levels of the sheep have not been widely investigated. Many of the early studies involved measurements of single samples obtained by venepuncture, a stressful procedure now known to affect prolactin release in the

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Section: Administration Of Thyrotrophin-releasingfactormentioning

confidence: 99%

Prolactin Release in the Sheep

Ge¹,

Moseley²,

McNeilly³

1974

Reproduction

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“…of PRL by these GH cell strains can be correlated with the amounts of cytoplasmic RNAPRL sequences detected by cell-free translational assay and by hybridization to cDNAPRL (DNA complementary to mRNAPRL) (1). PRL synthesis in PRL' GH4G1 cells can be further stimulated by treating the cells with thyrotropin-releasing hormone (TRH) (2,3). This effect ofTRH on PRL synthesis' can also be correlated.with increased cytoplasmic mRNAPRL sequences (4)(5)(6).…”

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confidence: 99%

Mechanism of induction of prolactin synthesis in GH cells

Biswas

Hanes

Brennessel

1982

Proc. Natl. Acad. Sci. U.S.A.

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Prolactin-specific RNA (RNApRL) in total nuclear RNA and in cytoplasmic poly(A)+RNA isolated from GH (rat pituitary) cells was selectively hybridized to immobilized cloned cDNApRL. Agarose gel electrophoresis. of the nuclear RNAPRL sequences eluted from the nitrocellulose filters revealed several RNA species of approximately 25-30, 18-19, and 12-13 S. Only the 12-13 S RNA species could be detected in the cytoplasmic poly(A)+RNA fraction. Comparative analysis oftotal nuclear RNA of control and thyrotropin-releasing hormone (thyroliberin)-treated cells by the reverse Southern blot technique demonstrated increased levels of all the nuclear RNAPRL species in hormone, treated cells. Nuclear and cytoplasmic RNAPRL sequences in control and treated cells were quantitated by molecular hybridization to clonedcDNApRL. The 2-to 34old stimulation ofPRL production by thyrotropin-releasing hormone-treated GH4C1 cells could be correlated to the. corresponding increase of nuclear RNAPRL sequences. The hybrid strain, which produces 1/5th the amount of PRL that the parent GH4Cj does, had 1/5th the amounts of nuclear RNAPRL sequences. Thyrotropin-releasing hormone affected neither prolactin production nor nuclear RNAPRL level in 928-9b cells. RNAPRL sequences could not be detected either in nuclei or in cytoplasm of prolactin nonproducing F1BGH12C, cells. However, prolactin production could be induced and RNAPRL sequences could be detected in the total nuclear.RNA and in cytoplasmic poly(A)+RNA fraction after treatment-of this GH cell substrain with 5-bromodeoxyuridine. These results demonstrate that differential basal prolactin production and 'its modulation by thyrotropin-releasing hormone and by 5-bromodeoxyuridine can be correlated to the altered levels'of nuclear RNAPRL sequences in the three GH cell strains.Prolactin (PRL) production in a hybrid strain (928-9b) (8). However, it has not~been known whether the increased PRL production results from increased production of nuclear and cytoplasmic RNAPRL sequences. This investigation also demonstrates the close correlation ofBrdUrd-induced PRL synthesis with a concomitant increase in nuclear and cytoplasmic RNAPRL sequences, from undetectable levels to detectable amounts. MATERIALS AND METHODSGH cells are clonal strains of rat pituitary tumor cells in culture (9). Isolation, growth conditions, and properties of the three substrains used in this investigation have been described in detail (1).Isolation of Nuclear and Cytoplasmic RNA. Isolation of nuclei and cytoplasm and of total RNA and poly(A)+RNA from these subcellular fractions has been described (10,11 by insertion of cDNAPRL (approximately 900 base pairs) into plasmid pBR322 at the Pst I site.

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“…TRH has been shown to potentiate PRL release from lactotrophs in a dose-dependent manner both in vitro and in vivo experiments (Bowers et al, 1971;Tashjian et al, 1971;Blake, 1974). It can successfully promote pituitary PRL secretion in oestrogen-primed male rats (Piercy and Shin, 1980), but not in normal male or lactating female (Grosvenor and Mena, 1980;Piercy and Shin, 1980;Riskind et al, 1984).…”

Section: Factors Stimulating Prolactin Releasementioning

confidence: 99%