Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.6.1.1 (adenylate cyclase)
19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Numerous biochemical pathways influence the synthesis and release of anterior pituitary hormones. Releasing factors extracted from the hypothalamus and prostaglandins (PGs) appear to alter a common biochemical activity, adenyl cyclase, in pituitary cells. Luteinizing hormone releasing hormone (LRH), prostaglandin (PGE1), 7 oxa-13-prostynoic acid and cycloheximide were tested for individual and interacting effects on the in vitro release of FSH, LH and prolactin from hemipituitaries of 15 day old female rats. LRH (10 ng/ml) consistently released both LH and FSH in all in vitro experiments and inhibited prolactin release in 1 of 2 experiments. Lower concentrations (5 and 1 ng/ml) also stimulated LH and FSH release but did not influence prolactin release. Concurrent depletion of stored LH and FSH in the gland was observed. PGE1 in a 6.5 hour incubation increased the storage of LH within the gland in the absence of LRH. In a 1.5 hour incubation in the presence of LRH, storage of LH was also increased. PGE1 had no effect on LH and FSH release; however, in 1 of 2 experiments it stimulted prolactin release in the absence of LRH. Prostynoic acid stimulted LH and FSH release but did not synergize with LRH action in the same tissue. Cycloheximide did not affect LH release during the first 30 minutes of incubation; however, the release during the subsequent 1 hour was significantly inhibited. Similar tissue also exposed to cycloheximide was still responsive to LRH during the latter 1 hour incubation period. Cycloheximide had no effect on prolactin storage and release from the same tissue.
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PMID:Interactions of prostaglandin E1 (PGE1) and LRH on anterior pituitary function. 76 87

Prolactin was shown to activate adenylate cyclase in broken cellular enzyme preparations from rat renal medulla. Likewise, vasopresin was effective on this enzyme system. Parathyroid hormone was similarly active in the renal cortex. The simultaneous administration of vasopressin and prolactin to medullary kidney slices did not result in an additive effect in stimulating medullary adenyl cyclase. Audioradiographic techniques revealed a selective and prolonged localization of intravenously injected 125I-prolactin to the thick limb of the loop of Henle, the distal tubule and the collecting duct. It is concluded that prolactin activates medullary adenylate cyclase, and may do so by occupying ADH receptors.
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PMID:Prolactin-induced stimulation of rat renal adenylate cyclase and autoradiographic localization to the distal nephron. 86 55

The effect of prolactin on adenyl cyclase, rate of fructose utilization, and glucose oxidation by human spermatozoa was studied. Prolactin stimulated all of these processes at a concentration generally available in seminal plasma. These results suggest that prolactin plays an important role in the energy metabolism of human spermatozoa.
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PMID:Effect of prolactin on metabolism of human spermatozoa. 97 1

2-Bromo-alpha-ergocryptine (CB154) administration to male rats produced a significant decrease in plasma prolactin levels without changing the LH and testosterone concentrations. The weights of the accessory sex tissues, testes, adrenals and kidney were unaltered by the treatment. Zinc concentration and distribution in the cell organelles of the prostatic tissue was markedly changed by CB154 treatment. No changes in the uptake of testosterone in vivo occurred in the treated animals. Prolactin did not consistently influence the prostatic adenyl cyclase activity in vitro and only at high concentrations was the testosterone uptake in vitro with cultures of prostatic tissue increased.
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PMID:The effect of 2-bromo-alpha-ergocryptine (CB154) administration of the hormone levels, organ weights, prostatic morphology and zinc concentrations in the male rat. 98 22

Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide originally isolated from ovine hypothalami and so called because of its ability to stimulate pituitary adenylate cyclase activity. Alternative amidation and proteolytic processing of prepro-PACAP gives rise to two bioactive-amidated forms, PACAP-NH2(1-38) (PACAP-38) and PACAP-NH2(1-27) (PACAP-27). 7B2 is a polypeptide of 185 amino acids which is predominantly found in secretory granules and is widely distributed in rat and human tissues. We investigated the ability of the two forms of PACAP to stimulate GH, prolactin and 7B2 release by the rat pituitary clonal cell line GH3, and ACTH and 7B2 by the mouse pituitary clonal cell line AtT-20. PACAP-38 and PACAP-27 stimulated 7B2 and GH/prolactin or ACTH secretion with a similar efficacy over the 2-h incubation period from GH3 and AtT-20 cells respectively. 7B2 secretion was also stimulated by corticotrophin-releasing factor (CRF-41) and vasoactive intestinal polypeptide (VIP) in AtT-20 cells, and thyrotrophin-releasing hormone (TRH) and VIP in GH3 cells. Addition of PACAP to CRF-41 resulted in an additive effect on ACTH secretion and a synergistic effect on 7B2 secretion in AtT-20 cells. No synergism was observed when PACAP was added together with TRH, either on GH and prolactin secretion or on 7B2 release from GH3 cells. PACAP-mediated 7B2 secretion from both cell lines and PACAP-stimulated ACTH release from AtT-20 cells were reduced by 5 mg octapeptide synthetic somatostatin analogue/l (5 mg SMS 201-995/l).
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PMID:Pituitary adenylate cyclase-activating polypeptide releases 7B2, adrenocorticotrophin, growth hormone and prolactin from the mouse and rat clonal pituitary cell lines AtT-20 and GH3. 131 Jul 12

(-)-(3-Hydroxyphenyl)-N-n-propylpiperidine ((-)-3-PPP) and transdihydrolisuride (terguride, TDHL) are partial dopamine D2 receptor agonists displaying low intrinsic activity at normosensitive postsynaptic dopamine D2 receptors in brain while activating prolactin-regulating dopamine D2 receptors in male rats with an efficacy close to that of full dopamine D2 receptor agonists. In the present study we examined the effects of these partial dopamine D2 receptor agonists on prolactin release in vitro. For this purpose prolactin-producing tumour cells which have been transfected with the dopamine D2 receptor cDNA and hence which express a dopamine D2 receptor (short isoform) that is functionally active with respect to inhibition of adenylate cyclase and prolactin release (GH4ZR7; Albert et al., J. Biol. Chem. (1990) 265, 2098) were used. While the full dopamine D2 receptor agonists, quinpirole, (+)-(3-hydroxyphenyl)-N-n-propylpiperidine ((+)-3-PPP) and dopamine induced a dose-dependent suppression of vasoactive intestinal peptide (VIP)-induced prolactin release from GH4ZR7, both (-)-3-PPP and terguride were inactive. Furthermore, the prolactin-suppressive effects of dopamine and quinpirole were significantly antagonized by pretreatment with (-)-3-PPP and terguride. It is concluded that partial dopamine D2 receptor agonists, which activate male lactotroph dopamine D2 receptors in vivo, may antagonize dopamine D2 receptors on GH4ZR7 cells. There were similar results from an experiment using monolayers of anterior pituitary cells from male rats. Thus, in this in vitro preparation (+)-3-PPP suppressed spontaneous prolactin release while (-)-3-PPP again was inactive.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Partial dopamine D2 receptor agonists antagonize prolactin-regulating D2 receptors in a transfected clonal cell line (GH4ZR7). 135 34

In GH3 cells and other clonal rat pituitary tumor cells, TRH has been shown to mediate its effects on prolactin release via a rise of cytosolic Ca2+ and activation of protein kinase C. In this study, we examined the role of protein kinase C in TRH-stimulated prolactin release from female rat primary pituitary cell culture. Both TRH and PMA stimulated prolactin release in a dose-dependent manner. When present together at maximal concentrations, TRH and PMA produced an effect which was slightly less than additive. Pretreatment of rat pituitary cells with 10(-6) M PMA for 24 hrs completely down-regulated protein kinase C, since such PMA-pretreated cells did not release prolactin in response to a second dose of PMA. Interestingly, protein kinase C down-regulation had no effect on TRH-induced prolactin release from rat pituitary cells. In contrast, PMA-pretreated GH3 cells did not respond to a subsequent stimulation by either PMA or TRH. Pretreatment of rat pituitary cells with TRH (10(-7) M, 24 hrs) inhibited the subsequent response to TRH, but not PMA. Forskolin, an adenylate cyclase activator, stimulated prolactin release by itself and in a synergistic manner when incubated together with TRH or PMA. The synergistic effects of forskolin on prolactin release was greater in the presence of PMA than TRH. Down-regulation of protein kinase C by PMA pretreatment abolished the synergistic effect produced by PMA and forskolin but had no effect on those generated by TRH and forskolin. sn-1,2-Dioctanylglycerol (DOG) pretreatment attenuated the subsequent response to DOG and PMA but not TRH. The effect of TRH, but not PMA, on prolactin release required the presence of extracellular Ca2+. In conclusion, the mechanism by which TRH causes prolactin release from rat primary pituitary cells is different from that of GH3 cells; the former is a protein kinase C-independent process whereas the latter is at least partially dependent upon the activation of protein kinase C.
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PMID:PMA-sensitive protein kinase C is not necessary in TRH-stimulated prolactin release from female rat primary pituitary cells. 145 79

It is still undetermined which GTP-binding (G) protein is involved in the regulation of prolactin (PRL) release and through which effector. This study shows that, when compared to normal pituitary tissue, the levels of alpha o protein were very low in dopamine (DA)-resistant, PRL-secreting pituitary tumors 7315a and MtTW15, while alpha o mRNA was present in the two tumors. In the MtTW15 tumor alpha i1, alpha i2 and alpha i3 levels were decreased while those of alpha s42 and alpha s47 were increased, and in the 7315a tumor alpha i2, alpha i3 and beta levels were decreased and those of alpha s47 increased. In an estrone-induced, DA-sensitive prolactinoma the levels of alpha i3 were greatly reduced. DA was unable to inhibit basal PRL release by 7315a and MtTW15 and basal cAMP accumulation by adenomatous and MtTW15 cells. Vasoactive intestinal peptide (VIP) increased both cAMP accumulation and PRL release by all cell preparations which could be suppressed by DA with adenomatous and 7315a but not with MtTW15 cells. These and previously published results provide circumstantial evidence that alpha o, alpha i1 and alpha i3 are all involved in the transduction of the DA inhibitory message while alpha s47 transduces cAMP activating messages and alpha s42 is responsible for the constitutive activation of L-type Ca2+ channels, adenylate cyclase and baseline PRL release.
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PMID:G proteins in normal rat pituitaries and in prolactin-secreting rat pituitary tumors. 165 58

Interleukin-6 (IL-6) is a pleiotropic cytokine exerting many immunological and non immunological actions. The cytokine binds to a specific receptor, whose activation induces the association with a novel transducer, the glycoprotein gp 130. Here we present our results about the effect of IL-6 on both hormone secretion and second messenger systems at pituitary level, and the production of IL-6 from cells of central nervous system. IL-6 inhibited basal, VIP and TRH-stimulated prolactin (PRL) secretion from single lactotropes, studied by means of reverse hemolytic plaque assay, whereas in primary cultures of anterior pituitary cells, according to the literature, the cytokine stimulated prolactin secretion. IL-6 did not affect basal adenylate cyclase activity, inositol phosphate production, and cytosolic calcium concentration. Conversely, the preincubation of pituitary cells with interleukin-6 for 20 min significantly reduced VIP- and forskolin-stimulated adenylate cyclase activity, as well as inositol phosphate production and free cytosolic calcium increase induced by TRH.
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PMID:Role of interleukin-6 in the neuroendocrine system. 166 73

The effects of FCE 23884 [4-(9,10-didehydro-6-methylergolin-8 beta-yl) methyl-piperazine-2,6-dione] were examined using a variety of biochemical methods. In vitro assays showed that FCE 23884 bound to D-2, alpha-2 and 5-hydroxytryptamine1A sites with Ki values of 6.5, 4.0 and 4.0 nM, respectively. The affinity for D-1 and S-2 receptors was moderate (submicromolar range) and slight or negligible for alpha-1, cholinergic and sigma receptors. In normal rats, FCE 23884 accelerated markedly dopamine (DA) turnover in the neostriatum and nucleus accumbens as indicated by the increased ratios of dihydroxphenyl acetic acid/DA and homovanillic acid/DA. The compound enhanced DA synthesis and utilization rate. After gamma-butyrolactone treatment, a model to study DA autoreceptors function, FCE 23884 almost antagonized completely the gamma-butyrolactone reversal induced by apomorphine on l-dihydroxyphenylalanine accumulation in the two brain areas. In addition, FCE 23884 induced a rapid 20-fold increase of serum prolactin confirming its DA antagonistic profile in normal rats. In contrast with these antidopaminergic properties, FCE 23884 consistently stimulated basal adenylate cyclase activity in vitro (ED50 = 0.6 microM) and elicited a rapid increase of cyclic AMP formation in the neostriatum of normal (35%) and reserpinized (82%) rats in vivo. Furthermore in this last condition both the DA turnover and synthesis rate in the neostriatum and nucleus accumbens decreased after treatment with FCE 23884. These neurochemical data support the behavioral studies indicating that FCE 23884 possesses mixed DA antagonist and agonist properties depending on the experimental conditions, the distinguishing factor being presence or absence of DA.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:FCE 23884, substrate-dependent interaction with the dopaminergic system. II. Preclinical biochemical studies. 168 Oct 88


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