Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin-6 (IL-6) was secreted by cultured cells of 7 out of 11 human pituitary adenomas that were examined. Interleukin-1 (IL-1) stimulated IL-6 release after a 24-h incubation period in five of the seven IL-6-secreting adenoma cultures and in all seven after 72 h. Tumour necrosis factor, interferon-gamma and epidermal growth factor did not significantly affect IL-6 secretion. Interleukin-1 failed to induce measurable IL-6 in the cultures that did not secrete IL-6 under basal conditions. Prostaglandin E2 did not influence basal IL-6 secretion and indomethacin did not inhibit IL-1-stimulated IL-6 release. In addition, pertussis toxin had no effect on IL-1-stimulated IL-6 release. The growth hormone (GH) secretory response to IL-1 varied, with stimulation in one GH-secreting adenoma culture, no significant effect in a second and inhibition in a third. Interleukin-1 did not significantly affect the release of prolactin, thyrotrophin, luteinizing hormone or follicle-stimulating hormone in any of the adenoma cultures. This study provides evidence that IL-1 is a stimulator of IL-6 release from cultured human pituitary adenoma cells that secrete IL-6. Stimulation of IL-6 release by IL-1 in these tumour cells is probably not mediated by prostaglandins or by a pertussis toxin-sensitive mechanism.
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PMID:Interleukin-1 stimulates the release of interleukin-6 from cultured human pituitary adenoma cells. 839 Nov 94

The alpha subunits of the stimulatory and inhibitory G proteins, Gs alpha and Gi alpha, activate transmembrane-signaling systems involved in the control of cell proliferation. We have investigated the pattern of expression of Gi alpha subtypes and Gi alpha-mediated proliferative responses in the human thyroid. Human thyroid membranes contain two subtypes of Gi alpha, Gi alpha-1 and Gi alpha-2, as assessed by using specific antibodies. The expression of Gi alpha-1 is under tight control by thyrotropin in vivo and in primary cultures of thyroid epithelial cells. In contrast, Gi alpha-1 is expressed in the absence of thyrotropin in thyroid autonomous adenoma, an endocrine-active tumor, and its levels are not regulated by thyrotropin in thyroid epithelial cells prepared from these tumors. If thyroid epithelial cells are treated with pertussis toxin to block signal transduction via Gi, the mitogenic response to serum factors is reduced. These observations demonstrate that Gi subtypes transmit growth stimuli in the human thyroid. The constitutive expression of Gi alpha-1 in autonomous adenoma may allow for the unregulated stimulation of thyroid cell proliferation by a yet unidentified signaling pathway and, thus, be causally related to autonomous growth of thyroid cells.
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PMID:Stimulation of human thyroid growth via the inhibitory guanine nucleotide binding (G) protein Gi: constitutive expression of the G-protein alpha subunit Gi alpha-1 in autonomous adenoma. 843 24

SRIF activates an inwardly rectifying K+ current in human GH-secreting adenoma cells. Activation of this K+ current induces hyperpolarization of the membrane and abolishment of action potential firing. This mechanism is an essential mechanism for SRIF-induced decrease in intracellular Ca2+ concentration and inhibition of GH secretion. The activation of the inwardly rectifying K+ current is mediated by a pertussis toxin-sensitive G protein. In this article, the expression of the pertussis toxin-sensitive G protein alpha-subunits in the human GH-secreting adenoma cells were analyzed by RT-PCR, and the G protein transducing the SRIF-induced activation of this inwardly rectifying K+ current was investigated. RT-PCR of the messenger RNA from two human GH-secreting adenomas revealed that all G alpha(i1), G alpha(i2), G alpha(i3), and G alpha(o) were expressed in these adenomas. Primary cultured cells from these two adenoma cells were investigated under the voltage clamp of the whole-cell mode. Specific antibodies against the carboxyl terminus of G protein alpha-subunits were microinjected into the cells. Microinjection of antibody against the carboxyl terminal sequence of G alpha(i3) attenuated the SRIF-induced activation of the inwardly rectifying K+ current, whereas antibody against the common carboxyl terminal sequence of G alpha(i1) and G alpha(i2) did not. These data indicate that the G protein transducing the SRIF-induced activation of the inwardly rectifying K+ current is Gi3.
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PMID:Gi3 mediates somatostatin-induced activation of an inwardly rectifying K+ current in human growth hormone-secreting adenoma cells. 916 29

Evidence from use of pertussis and cholera toxins and from NaF suggested the involvement of G proteins in GnRH regulation of gonadotrope function. We have used three different methods to assess GnRH receptor regulation of G(q/11)alpha subunits (G(q/11)alpha). First, we used GnRH-stimulated palmitoylation of G(q/11)alpha to identify their involvement in GnRH receptor-mediated signal transduction. Dispersed rat pituitary cell cultures were labeled with [9,10-(3)H(N)]-palmitic acid and immunoprecipitated with rabbit polyclonal antiserum made against the C-terminal sequence of G(q/11)alpha. The immunoprecipitates were resolved by 10% SDS-PAGE and quantified. Treatment with GnRH resulted in time-dependent (0-120 min) labeling of G(q/11)alpha. GnRH (10(-12), 10(-10), 10(-8), or 10(-6) g/ml) for 40 min resulted in dose-dependent labeling of G(q/11)alpha compared with controls. Cholera toxin (5 microg/ml; activator of G(i)alpha), pertussis toxin (100 ng/ml; inhibitor of G(i)alpha actions) and Antide (50 nM; GnRH antagonist) did not stimulate palmitoylation of G(q/11)alpha above basal levels. However, phorbol myristic acid (100 ng/ml; protein kinase C activator) stimulated the palmitoylation of G(q/11)alpha above basal levels, but not to the same extent as 10(-6) g/ml GnRH. Second, we used the ability of the third intracellular loop (3i) of other seven-transmembrane segment receptors that couple to specific G proteins to antagonize GnRH receptor-stimulated signal transduction and therefore act as an intracellular inhibitor. Because the third intracellular loop of alpha1B-adrenergic receptor (alpha1B 3i) couples to G(q/11)alpha, it can inhibit G(q/11)alpha-mediated stimulation of inositol phosphate (IP) turnover by interfering with receptor coupling to G(q/11)alpha. Transfection (efficiency 5-7%) with alpha1B 3i cDNA, but not the third intracellular loop of M1-acetylcholine receptor (which also couples to G(q/11)alpha), resulted in 10-12% inhibition of maximal GnRH-evoked IP turnover, as compared with vector-transfected GnRH-stimulated IP turnover. The third intracellular loop of alpha2A adrenergic receptor, M2-acetylcholine receptor (both couple to G(i)alpha), and D1A-receptor (couples to G(s)alpha) did not inhibit IP turnover significantly compared with control values. GnRH-stimulated LH release was not affected by the expression of these peptides. Third, we assessed GnRH receptor regulation of G(q/11)alpha in a PRL-secreting adenoma cell line (GGH(3)1') expressing the GnRH receptor. Stimulation of GGH(3)1' cells with 0.1 microg/ml Buserelin (a metabolically stable GnRH agonist) resulted in a 15-20% decrease in total G(q/11)alpha at 24 h following agonist treatment compared with control levels; this action of the agonist was blocked by GnRH antagonist, Antide (10(-6) g/ml). Neither Antide (10(-6) g/ml, 24 h) alone nor phorbol myristic acid (0.33-100 ng/ml, 24 h) mimicked the action of GnRH agonist on the loss of G(q/11)alpha immunoreactivity. The loss of G(q/11)alpha immunoreactivity was not due to an effect of Buserelin on cell-doubling times. These studies provide the first direct evidence for regulation of G(q/11)alpha by the GnRH receptor in primary pituitary cultures and in GGH3 cells.
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PMID:Regulation of G(q/11)alpha by the gonadotropin-releasing hormone receptor. 917 Dec 37

Autism may be a disorder linked to the disruption of the G-alpha protein, affecting retinoid receptors in the brain. A study of 60 autistic children suggests that autism may be caused by inserting a G-alpha protein defect, the pertussis toxin found in the DPT vaccine, into genetically at-risk children. This toxin separates the G-alpha protein from retinoid receptors. Those most at risk report a family history of at least one parent with a pre-existing G-alpha protein defect, including night blindness, pseudohypoparathyroidism or adenoma of the thyroid or pituitary gland. Natural vitamin A may reconnect the retinoid receptors critical for vision, sensory perception, language processing and attention. Autism spectrum disorders have increased from 1 in 10 000 in 1978 to 1 in 300 in some US communities in 1999. Recent evidence indicates that autism is a disorder of the nervous system and the immune system, affecting multiple metabolic pathways.
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PMID:Is autism a G-alpha protein defect reversible with natural vitamin A? 1086 50

The mechanism of dopamine D(2) agonist-induced inhibition of GH secretion from GH-secreting adenoma cells was investigated by measurement of intracellular calcium concentration ([Ca(2+)] (i)) and static incubation experiment. Bromocriptine decreased [Ca(2+)](i) in a concentration-dependent manner through D(2) receptor. The inhibition was abolished by pertussis toxin pretreatment. Bromocriptine did not decrease [Ca (2+)](i) after nitrendipine had decreased it. 8Br-cAMP increased [Ca(2+)](i) but application of bromocriptine decreased it, suggesting that bromocriptine-induced inhibition of [Ca(2+)](i) is not dependent on bromocriptine-induced inhibition of adenylyl cyclase. Static incubation experiment revealed that bromocriptine inhibited GH secretion in a concentration-dependent manner. The inhibition was through D(2) receptor and was abolished by pertussis toxin pretreatment. 8Br-cAMP increased GH secretion. Bromocriptine decreased GH secretion even after 8Br-cAMP pretreatment. However, the GH release from cells incubated with bromocriptine alone was significantly less than that from cells incubated with bromocriptine after 8Br-cAMP pretreatment, suggesting a modulatory action of cAMP system in bromocriptine response.
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PMID:Mechanism of D(2) agonist-induced inhibition of GH secretion from human GH-secreting adenoma cells. 1641 Jun 72


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