Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The stimulatory effects of FSH on Sertoli cell functions such as cAMP accumulation, protein kinase activation, and RNA and protein synthesis wane during testis maturation. However, FSH receptors increase with age and addition of cAMP stimulates these biochemical events in Sertoli cells from animals of any age. In order to determine if this loss of responsiveness to FSH was due to an inability to stimulate adenylyl cyclase, the hormonal responsiveness of this enzyme was investigated as a function of testicular development. In agreement with intact cell studies, adenylyl cyclase activity was found to be stimulated by FSH 2- to 3-fold in homogenates of testes from immature (5-20 days of age) Sertoli cell-enriched rats, while no stimulation of the enzyme by FSH was observed in similar homogenates from Sertoli cell-enriched animals 20 days of age or older. The possibility of a decrease in enzyme sensitivity to the gonadotropin as a function of maturation ws ruled out by dose-response studies. Catalytic activity of the enzyme was retained with increasing animal age as evidenced by the ability of fluoride (10 mM) to stimulate basal activity 4-fold. Hormonal responsiveness of the Sertoli cell adenylyl cyclase of mature animals could be restored, however, either by addition of the nonmetabolizable guanosine 5'-triphosphate analog, 5'-guanylyl-imidodiphosphate to homogenates or by preparation of membrane particles. We found that 5'-guanylyl-imidodiphosphate selectively potentiated FSH effects on cyclase in testicular homogenates from mature animals while having no effect on the relative degree of hormone stimulation in homogenates from immature animals, and that in contrast to homogenates, testicular membrane preparations retain their FSH responsiveness upon animal maturation.
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PMID:Developmental changes in the hormonal regulation of rat testis Sertoli cell adenylyl cyclase. 679 47

The acquisition of FSH receptor during preantral folliculogenesis is believed to be a key step in the subsequent development of follicles. We examined the interaction between activin and cAMP in FSH receptor induction in rat granulosa cells by measuring 125I-FSH binding and FSH receptor mRNA. In the 125I-FSH binding study, 0.2 mM 8-Br-cAMP and 1 microM forskolin were maximally effective in FSH receptor induction (169 and 220% respectively of control), while higher concentrations gave attenuated responses. It appears that cAMP has ambivalent effects on FSH receptor induction depending on the concentration and length of exposure. Activin alone dramatically increased the number of FSH receptors (314% of control). Moreover, synergistic effects of activin and 8-Br-cAMP or forskolin were observed on FSH receptor induction: a combination of activin (80 ng/ml) and low doses of 8-Br-cAMP (0.2 mM) or forskolin (1 microM) was most effective (160 or 140% of that induced by activin alone) and receptor levels reached a maximum at 24 h. These levels than markedly decreased after 72 h of incubation. Northern blot analysis revealed that the combination of activin (80 ng/ml) and 8-Br-cAMP (0.2 mM) or forskolin (1 microM) increased FSH receptor mRNA to about 140% of that induced by activin alone. These results indicate that activin and cAMP induced FSH receptor synergistically. However, activin did not enhance the production of cAMP induced by forskolin. In addition, a protein kinase A inhibitor (H89) (2 microM), which inhibited the effects of forskolin, had no effect on the action of activin.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interaction between activin A and cAMP in the induction of FSH receptor in cultured rat granulosa cells. 749 May 22

The human glycoprotein alpha-subunit is the common subunit of the heterodimeric hormones CG (hCG), TSH, LH, and FSH. Human glycoprotein alpha-subunit is produced eutopically in placenta, pituitary, and choriocarcinoma and ectopically in a large variety of human tumors. We report ectopic glycoprotein alpha-subunit messenger RNA (mRNA) and peptide production in the human hepatoma cell line, NPLC. Neither hCG beta mRNA nor intact hCG peptide was detected. Antimetabolite regulation of glycoprotein alpha-subunit expression in NPLC cells resembled that found in choriocarcinoma cells in that it was stimulated by hydroxyurea. In addition, glycoprotein alpha-subunit mRNA expression and transcription in NPLC were stimulated by activators of the protein kinase A and C second messenger pathways, as well as by glucocorticoid. Glucocorticoid augmented glycoprotein alpha-subunit gene transcription by phorbol ester and forskolin, in contrast to its simultaneous inhibitory effect on phorbol ester activation of the CRH gene, which is also ectopically expressed in these cells. Glucocorticoid thus modulates the activation of these genes by phorbol ester in opposite directions, despite their identical cellular context. The NPLC cell line provides a new model for the study of human glycoprotein alpha-subunit gene regulation and free glycoprotein alpha-subunit secretion. In addition, it should be useful for investigating the role that specific cis-acting DNA sequences play in glucocorticoid modulation of gene induction by second messenger pathways.
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PMID:Regulation of the ectopically expressed human glycoprotein alpha-subunit gene in the human hepatoma cell line NPLC. 750 28

The somatic Sertoli cells of the testis are major targets for FSH and are important for the regulation of spermatogenesis. The binding of FSH to Sertoli cells activates the cAMP-dependent protein kinase A signaling pathway, resulting in phosphorylation of the cAMP response element-binding protein (CREB), which is required to transactivate genes containing cAMP response elements (CREs). Here we show that the addition of forskolin to cultured primary Sertoli cells results in the phosphorylation of CREB within 2-5 min. Phospho-CREB levels remain elevated with continued forskolin stimulation, but fall by 60% within 5 min after the removal of forskolin. In addition, we found that 8-bromo-cAMP induces CREB RNA accumulation in the Sertoli cells. Transient transfections of primary Sertoli cells with CREB promoter-chloramphenicol acetyltransferase reporter plasmids define a conserved 300-base pair region of the CREB promoter surrounding the transcription start site that is required for both basal and cAMP-inducible expression of the CREB gene. This region of the promoter contains three Sp1-binding sites flanking the transcription initiation site and two CREs located 65 and 85 base pairs downstream of the transcription initiation site. We show that the Sp1 motifs bind Sp1 in Sertoli extracts and contribute to basal promoter activity, and that the CREs bind CREB and are essential for cAMP induction of CREB gene transcription. These findings support the model of FSH- and cAMP-mediated CREB autoregulation of its own promoter and may explain the dramatic stage-specific oscillations in Sertoli cells of CREB messenger RNA levels during the 12-day cycles of spermatogenesis in rat seminiferous tubules.
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PMID:Expression of the gene encoding transcription factor cyclic adenosine 3',5'-monophosphate (cAMP) response element-binding protein (CREB): regulation by follicle-stimulating hormone-induced cAMP signaling in primary rat Sertoli cells. 762 90

Rat granulosa cell-derived insulin-like growth factor (IGF) binding proteins (BPs) have been found subject to biphasic dose-dependent regulation by FSH under in vitro circumstances. Since cAMP may play an intermediary role in FSH hormonal action, we have undertaken to characterize the A kinase-mediated regulation of the elaboration of IGFBPs by cultured rat granulosa cells. Treatment with increasing concentrations of prostaglandin E2 or choleragen, both established cAMP-generating agonists, produced biphasic dose-dependent regulation of the release of the major 28-29 kilodalton (kDa) IGFBP species while promoting the release of their minor 24 (and 19) kDa counterparts. Similar effects were noted for other cAMP-generating agonists including vasoactive intestinal peptide and forskolin (a potent activator of adenylate cyclase). Moreover, concomitant treatment with a functionally inert low dose (10(-7) M) of forskolin, substantially potentiated the FSH (10 ng/ml)-mediated inhibition of the elaboration of the 28-29 kDa IGFBPs. Application of decreasing dilutions of the invasive adenylate cyclase toxin of bordetella pertussis (but not of an inactive mutant strain) yielded monophasic dose-dependent modulation of the release of the 28-29 kDa IGFBPs while effecting biphasic regulation of the 24 kDa moiety. Concurrent treatment with 1-methyl-3-isobutylxanthine (a potent inhibitor of cAMP phosphodiesterase activity) at the 10(-4) M level resulted in profound (P < 0.05) inhibition of the (low dose) FSH (3 ng/ml)-supported accumulation of the major 28-29 kDa IGFBP species, an effect associated with modest (2.5-fold) induction (P < 0.05) of the minor 24 kDa IGFBP moiety. Lastly, provision of increasing concentrations of nondegradable lipophilic analogs of cAMP (i.e. (Bu)2cAMP and 8-bromoadenosine cAMP resulted in biphasic dose-dependent modulation of the release of the major 28-29 kDa IGFBP doublet while producing an increase in the accumulation of the minor 24 kDa IGFBP species. Taken together, these observations suggest that the ability of low dose FSH to stimulate and of high dose FSH to inhibit the elaboration of the 28-29 kDa IGFBP species may entail activation of the A-kinase transduction pathway. Similar conclusions appear to apply for the ability of FSH to regulate (albeit at a lower response sensitivity level) the biphasic elaboration of the 24 kDa IGFBP moiety. As such, these observations point out the disparate response sensitivities of distinct IGFBP species, thereby suggesting a novel potent mechanism through which FSH may determine the relative distribution pattern of granulosa cell-derived IGFBPs and the consequent overall IGF responsiveness of this cell type.
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PMID:A kinase-mediated regulation of granulosa cell-derived insulin-like growth factor binding proteins (IGFBPs): disparate response sensitivities of distinct IGFBP species. 768 61

During the development of preovulatory follicles, tonic levels of FSH (and steroid) induce expression of aromatase, the LH receptor, and RII beta in a coordinate manner. Despite the similar temporal increase in steady-state levels of mRNA encoding these proteins, the cis-acting DNA elements and trans-acting factors regulating each gene are distinct (Richards, 1993). Whereas the aromatase gene has a TATA motif and a single transcriptional initiation site (Fitzpatrick and Richards, 1993), both the LH receptor (Wang et al., 1992; Tsai-Morris et al., 1993) and RII beta (Kurten et al., 1992; Luo et al., 1992) genes have promoters that are GC rich, lack TATA motifs, and initiate transcription at multiple sites. The aromatase promoter appears to be regulated, in part, by SF-1, a CRE-like region, and possibly another or overlapping region binding an Ad3BP-like factor. The RII beta promoter has a region that binds several nuclear proteins, whose identity is not yet known. Likewise, the LH receptor promoter elements have yet to be clearly defined (Figures 2, 4, and 25; Kurten et al., 1992). FSH can also induce the expression of at least three immediate-early genes that encode novel kinases or kinase-like proteins (Figure 25). One of these is called serum-inducible kinase (snk) (Simmons et al., 1992), another is serum and glucocorticoid regulated kinase (sgk) (Webster et al., 1993), and a third is called pole kinase (Clay et al., 1993). Steady-state levels of snk and sgk mRNA are induced rapidly (within a few hours) by FSH in granulosa cells prior to the appearance of transcripts for aromatase, LH receptor, and RII beta (T. Alliston and J. S. Richards, in preparation). The functional role of these kinases in the initial response of granulosa cells to tonic (not surge) levels of FSH remains to be elucidated. The cellular signaling pathways mediating the effects of the LH surge appear equally or more complex (Fig. 25). Based on data presented herein, as well as on analyses of the cloned and expressed LH receptor (Guderman et al., 1992), it is clear that low concentrations of LH stimulate adenylyl cyclase, cAMP production, and activation of protein kinase A. Higher (surge) concentrations of LH also increase IP3 and activation of protein kinase C. GnRH has been used in several studies to examine the ability of the protein kinase C pathway to mimic effects of high LH.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ovarian cell differentiation: a cascade of multiple hormones, cellular signals, and regulated genes. 774 Jan 59

Follistatin is a 35-kilodalton monomer isolated from follicular fluid that acts on pituitary gonadotropes to suppress the production of FSH. Transfection of rat granulosa cells with specific oncogenes, such as simian virus 40 (SV40) DNA and Ha-ras oncogene, leads to their immortalization concomitant with preservation of their capacity for inducible steroidogenesis. Experiments were designed to investigate the regulation of follistatin messenger RNA (mRNA) accumulation upon stimulation with forskolin, 2-O-tetradecanol-phorbol-13-acetate (TPA), FSH, and hCG in four different granulosa cell lines. Granulosa cells were transfected with SV40 DNA alone (POGS5); with SV40 DNA and Ha-ras oncogene (POGRS1); with SV40 DNA, Ha-ras oncogene, and LH/CG receptor (GLHR15); or with FSH receptor (GFSHR17) expression plasmid. Cells were cultured to reach confluence and then stimulated for 6 or 24 h with ovine FSH (oFSH; 0.004-4 nM), hCG (9 nM), forskolin (50 microM), and TPA (50 nM), alone or in combination. In the POGS5 cell line, forskolin caused a 15-fold stimulation of follistatin mRNA after 24-h incubation. The POGRS1 cell line showed a time-dependent stimulation of follistatin gene expression induced by both forskolin (5.7-fold) and TPA (9.4-fold). In the GFSHR17 cells, forskolin, oFSH, and TPA induced an increase in follistatin mRNA. When oFSH (1.6 nM) was added to cells treated with forskolin (50 microM) or TPA (50 nM), no additional stimulation was observed. The GLHR15 cell line treated with hCG showed a 2.7-fold increase in follistatin mRNA accumulation within 6 h. Our data demonstrate that 1) follistatin mRNA is detectable and induced by forskolin and TPA in transformed granulosa cell lines that do not express the FSH or LH receptors; 2) in the GFSHR17 cell line, FSH, forskolin, and TPA caused a time- and dose-dependent regulation of the gene; and 3) follistatin gene expression is up-regulated by hCG in the GLHR15 cell line. We conclude that these transformed steroidogenic cell lines can serve as a useful model to study the regulation of follistatin gene expression, a peptide known to regulate pituitary and ovarian hormone secretion and differentiation of granulosa cells by its activin-binding action. Moreover, this gene can be regulated in immortalized granulosa cells by both the protein kinase A and protein kinase C pathways, although these cells express the large T antigen and the Ha-ras oncogenic proteins.
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PMID:Regulation of follistatin messenger ribonucleic acid in steroidogenic rat granulosa cell lines. 778 14

In granulosa cells, growth factor IGF I plays a major role in both growth and differentiation, acting through an autocrine/paracrine mechanism, and its production is regulated by FSH, via cyclic AMP (cAMP). As protein kinase C is also involved in granulosa cell function, we investigated the possibility that its activation could balance the positive effects of FSH. Using pig granulosa cells cultured in vitro, we studied the effects of protein kinase C activation by tetradecanoylphorbol acetate (TPA) on IGF I mRNA level. We also checked morphological modifications, cAMP production and steroidogenesis at the P450 side chain cleavage mRNA and progesterone levels. Our data demonstrate that protein kinase C activation antagonizes the in vitro FSH-induced differentiation, particularly morphological modifications and accumulation of IGF I mRNA. These inhibitory effects on FSH responses suggest that there could be a balance between protein kinase A and protein kinase C pathways in regulating differentiation in pig granulosa cells.
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PMID:Protein kinase C inhibition of in vitro FSH-induced differentiation in pig granulosa cells. 779 38

We have recently shown that FSH, LH, and prolactin (PRL)--alone or combined--act as luteotropins when incubated with luteal cells from pregnant hamsters (Yuan and Greenwald, Biol Reprod 1994; 51:43-49). The purpose of the present study was to determine which second messenger systems are affected by these hormones with progesterone (P4) synthesis as the principal endpoint after 4 h of incubation with 100,000 luteal cells. Luteal cells on Days 4, 10, or 12 of pregnancy were incubated with the following reagents: 10 ng of recombinant human FSH (r-hFSH), ovine (o) FSH, oLH, oPRL, forskolin, db-cAMP, protein kinase A inhibitor (PKI), protein kinase C activator (phorbol 12-myristate 13-acetate; PMA), or various combinations of the reagents. Forskolin and db-cAMP each stimulated P4 in a dose-dependent manner, while PKI significantly inhibited forskolin-, r-hFSH-, oFSH-, and oLH-stimulated P4 on Day 4 of pregnancy. PMA (0.001-1.0 microM) did not affect basal P4 on Day 4, 10, or 12 of pregnancy; however, 100 nM PMA inhibited db-cAMP-, forskolin-, oFSH-, and oLH-stimulated P4 synthesis on Days 4 and 12. The antagonistic effects of PMA were reversed in all cases by concurrent incubation with a PKC inhibitor, H-7. On Day 4 of pregnancy, P4 was stimulated by oFSH and oLH with the highest levels observed in medium stimulated by the luteotropic complex of oFSH, oLH, and oPRL. Recombinant hFSH enhanced P4 production in a dose-dependent manner; doses of 10 ng and above resulted in statistically significant differences from the control values (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Luteotropic effects of follicle-stimulating hormone (FSH): II. FSH luteinizing hormone, and prolactin effects on second messenger systems in the corpus luteum of the pregnant hamster. 780 18

The present study investigated the importance of pulsatile vs. continuous protein kinase-C (PKC) stimulation in regulating pituitary gene expression. Adult female rat pituitaries were dissociated, and cells were plated for 48 h, then inserted into perifusion chambers (n = 5-8/group). Chambers received pulses of GnRH (100 pM) plus TRH (4 nM) or sn-1,2-dioctanoylglycerol (DOG; peak chamber concentration, 0.2, 1, or 5 mM; vehicle pulses to controls) every 60 min or a continuous infusion of phorbol 12-myristate 13-acetate (PMA; 20 nM). Secretory responses were determined in perifusate fractions collected after 2 and 22 h of perifusion. After 24 h of treatment, the cells were recovered, total RNA was extracted, and messenger RNAs (mRNAs) were measured by dot blot hybridization. The data revealed that GnRH plus TRH and both pulsatile (DOG) and continuous (PMA) PKC stimulation increased LH, FSH, TSH, and PRL secretory activity. Pulses of GnRH plus TRH increased PRL, alpha, TSH beta, and FSH beta mRNAs, but not LH beta mRNA. Pulsatile DOG only increased LH beta and PRL mRNAs, with maximal responses seen after the 1-mM dose for LH beta and the 0.2-mM dose for PRL. In contrast, PMA stimulated significant increases in alpha, LH beta, and TSH beta, but not PRL or FSH beta. These data show that alpha, TSH beta, LH beta, and PRL mRNA expression are regulated by PKC. Maximal increases are seen after continuous stimulation (via PMA), with the exception of PRL, which requires a pulsatile signal pattern. Thus, intermittent activation of PKC does not appear to play a major role in regulating pituitary gene expression.
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PMID:Regulation of gonadotropin, thyrotropin subunit, and prolactin messenger ribonucleic acid expression by pulsatile or continuous protein kinase-C stimulation. 782 22


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