Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Progesterone (P)-induced PRL secretion in estradiol (E)-primed monkeys is not due to direct pituitary stimulation, because lactotropes do not express progestin receptors (PR). However, the hypothalamus, particularly the tuberoinfundibular dopaminergic system (TIDA), plays a major role in the regulation of PRL secretion. To determine whether hypothalamic dopamine neurons are progestin target cells, the colocalization of PR and tyrosine hydroxylase (TH), a phenotypic marker of dopaminergic neurons, was examined with double immunocytochemistry. Two methods for visualizing the antigens were applied; the first was a dual peroxidase method, and the second was a peroxidase-alkaline phosphatase method. In addition, the question of whether E induces PR in dopamine neurons was explored. Spayed female monkeys were treated with empty Silastic capsules, E-filled capsules for a period of 28 days, or E capsules supplemented with P capsules for the last 14 days of E treatment. Only the E- plus P-treated monkeys exhibited an increase in serum PRL during the P treatment period. Frontal sections at the level of the optic chiasm and arcuate nucleus were examined for the colocalization of TH and PR. After E treatment, hypothalamic PR-positive cells increased in both intensity and number. Neurons expressing both TH and PR were detected in the rostral hypothalamus, lateral to the third ventricle (A11-rostral) and in a discrete subventricular population (A11-subvent). The lateral population continued caudally (A11-caudal). The A11-subvent population exhibited little steroid regulation. Of the remaining A11 TH neurons, approximately 20% exhibited PR in the spayed and E-treated groups. Addition of P doubled the percentage of PR-containing TH neurons in this group. Although very few TH-positive neurons in the ventral arcuate nucleus contained PR (A12-ventral), many double labeled neurons were observed in the dorsal arcuate region (A12-dorsal). Ventral arcuate TIDA neurons were not regulated by steroids, but E plus P increased PR expression in A12-dorsal. Double labeled cells were rarely seen in the zona incerta (A13) or the emerging ventral tegmental area (A10). In summary, P probably does not act directly on ventral arcuate TIDA neurons to stimulate PRL secretion. However, the frequency of PR-positive dopamine neurons in the A11-rostral, A11-caudal, and A12-dorsal groups increased with E and P treatment. Therefore, the contribution of the PR-positive periventricular dopamine neurons to progestin-stimulated PRL secretion may be important.
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PMID:Immunocytochemical colocalization of hypothalamic progestin receptors and tyrosine hydroxylase in steroid-treated monkeys. 135 39

The serum hormone (T3, FT3, T4, FT4, TSH, hTG, a-hTG, GH, PTH, PRL, Cortisol) concentrations, the inorganic phosphate complexes (HPO2-4, H2PO-4, NaHPO-4, KHPO-4, CaHPO4, MgHPO4) and the enzyme activities (Amylase, Lipase, AP, ACE, GOT, GPT, psi-ChE, CK, gamma-GT, LDH) were investigated in 13 haemodialysed children, 7 kidney-transplanted children and in 15 healthy controls. This study confirmed that the kidney plays an important role in the metabolism of hormones. Prior to kidney transplantation 8 of the 11 tested hormone levels of haemodialysed children significantly differed from those of healthy controls, however, after kidney transplantation only two parameters did. The effect of dialysis is the least on the CaHPO4 complex among the different inorganic phosphate complexes. This may play a role in vascular calcification in chronic renal failure patients. The amylase and lipase activity were elevated in haemodialysed group, while in kidney-transplanted children the angiotensin converting enzyme (ACE) and alkaline phosphatase (AP) differed from those of the control group.
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PMID:The serum hormone levels, phosphate complex concentrations and enzyme activities in haemodialysed and kidney-transplanted children. 169 May 69

The lipocortins are a family of calcium-dependent phospholipid-binding proteins that are induced by glucocorticoids and inhibit phospholipase-A2 activity. To determine whether the lipocortins affect the release of PRL from human decidua, decidual cells from term pregnancies were exposed to recombinant lipocortin-I for 96 h, with medium changes at 24-h intervals. Lipocortin-I (0.01-100 nM) caused a time- and dose-dependent inhibition of PRL release, with a half-maximal effective dose of 50 nM. PRL release was inhibited by 27%, 62%, 93%, and 98% at 24, 48, 72, and 96 h, respectively. The cells exposed to lipocortin-I did not release the enzymes alkaline phosphatase and lactic dehydrogenase, indicating that the inhibitory effect on PRL release was not due to cell death. In addition to inhibiting basal PRL release, lipocortin also completely inhibited the stimulation of PRL release by decidual PRL-releasing factor, a 23.5-kDa protein recently purified from human placenta that stimulates the synthesis and release of decidual, but not pituitary, PRL. Hydrocortisone and dexamethasone (0.1-10 microM) had no effect on PRL release, and arachidonic acid (2-100 microM) inhibited rather than stimulated PRL release. Western blot analysis demonstrated the presence of lipocortin-I in decidual cells and conditioned media. On Northern blot, decidual mRNA hybridized to an oligonucleotide for lipocortin-I. These results strongly suggest that lipocortin-I has an autocrine/paracrine role in regulation of the synthesis and release of PRL from human decidual cells.
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PMID:Lipocortin-I inhibits the synthesis and release of prolactin from human decidual cells: evidence for autocrine/paracrine regulation by lipocortin-I. 182 32

Twenty patients with stage D2 prostatic carcinoma were treated for up to 18 months with D-Trp-6-LH-RH. Results of more than 3 months of treatment on these 20 patients are reported. The analog was given SC once daily at a dose of 1,000 micrograms/day. All patients had bone pain and high levels of acid and alkaline phosphatase. After the first week of D-Trp-6-LH-RH administration, major decreases in bone pain and reversal of the signs of prostatism were observed. Acid phosphatase gradually fell, achieving normal values after 12 weeks. Initial plasma testosterone was within normal limits, but during treatment with D-Trp-6-LH-RH it fell to castration levels. Resting values of PRL, GH, TSH, and cortisol did not show significant changes. After TRH, TSH increased in five patients, but five did not respond. However, at 2 and 4 months, all patients released TSH in response to TRH. Two patients died during the treatment with D-Trp-6-LH-RH despite initial subjective responses and decreases in testosterone levels. The rise in acid phosphatase levels in these two patients was accompanied by a general deterioration, suggesting that they had androgen-independent cancer. One patient who developed progressive hepatic, bone, and pulmonary metastases in spite of previous orchiectomy was also treated with the analog. Three months later his acid phosphatase levels were within normal values, and partial regression of metastases was observed. These results demonstrate that D-Trp-6-LH-RH and other LH-RH agonists can be used as an effective endocrine therapy for advanced prostate carcinoma, thereby avoiding the side effects of estrogens or the psychological impact of surgical castration.
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PMID:Treatment of advanced prostatic carcinoma with D-Trp-6-LH-RH. 293 92

Two PRL-like glycoprotein hormone complexes were purified from the medium of cultured mouse conceptuses from day 10 of pregnancy: mouse placental lactogen-I (mPL-I) (29-32K), and mPL-I (36.5-42K). Sodium dodecyl sulfate-gel electrophoresis revealed that mPL-I (36.5-42K) is a complex of five proteins with mol wt of 36.5K, 37.5K, 39K, 40.5K, and 42K. Deglycosylation with peptide: N-glycosidase F or trifluoromethanesulfonic acid produced a single 29K protein. mPL-I (36.5-42K) was also sensitive to neuraminidase, but not to endo-beta-N-acetylglucosaminidase H or bacterial alkaline phosphatase. The production of intermediates from partial digestion of mPL-I (36.5-42K) with endo-beta-N-acetylglucosaminidase F indicated the presence of multiple glycosylation sites. mPL-I (29-32K) is a complex of three proteins with mol wt of 29K, 30.5K, and 32K. Treatment with peptide:N-glycosidase F or trifluoromethanesulfonic acid reduced the mol wt of the 30.5K and 32K bands to 28K. The 30.5K band was sensitive to endo-beta-N-acetylglucosaminidase H and endo-beta-N-acetylglucosaminidase F, but the 32K band was not. Neither band was sensitive to neuraminidase or bacterial alkaline phosphatase. The 29K band was resistant to all chemical and enzymatic treatments and is probably not glycosylated or phosphorylated. In the nonreduced state, neither form of mPL-I showed an increase in mobility over that of its reduced counterpart on sodium dodecyl sulfate-gel electrophoresis, indicating that neither form of mPL-I contains the large disulfide loop common to hormones of the PRL family. After iodination, all component proteins of both forms of mPL-I were found to bind to day 17 pregnant mouse liver membranes and were displaceable by excess mPL-II. In a radioreceptor assay, 125I-labeled mPL-I (36.5-42K) was displaced by mPRL or mPL-II, but not by mGH. An antiserum to both forms of mPL-I was generated, and a RIA employing mPL-I (36.5-42K) as the standard and radioligand was developed. Dilutions of day 10 pregnant maternal mouse serum and placental homogenate and a partially purified fraction of mPL-I (29-32K) produced displacement curves parallel to that of mPL-I (36.5-42K) standard curve. Five micrograms of mPRL, mPL-II, or mGH or 10 microliter day 17 pregnant or male mouse serum did not displace the radioligand from the antibody. mPL-I (36.5-42K) was lactogenic, but it did not possess LH-like bioactivity.
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PMID:Purification and partial characterization of two prolactin-like glycoprotein hormone complexes from the midpregnant mouse conceptus. 303 95

Effects of the dopamine agonist 2-bromo-alpha-ergocryptine (bromocriptine) on plasma and pituitary PRL and enzyme activities in lactating and postlactating rats have been investigated. Lactating rats which had been suckling their young for 3 days were given a single sc injection of bromocriptine or solvent. The treated and control animals were divided into 2 further groups. One group (lactating rats) was permitted to suckle their pups for a further 12 or 24 h; the young were removed from the other group (postlactating rats). Homogenates were prepared from the anterior pituitaries and assayed for organelle marker enzyme activities. When 0.5-500 micrograms bromocriptine were administered to lactating rats for 24 h, pituitary PRL was increased by all doses, but only the 500-micrograms dose significantly reduced plasma PRL. Total protein was unchanged, lysosomal acid PRL proteolytic activity increased 8-fold, N-acetyl-beta-glucosaminidase and beta-glucuronidase (lysosomes) were unchanged, acid phosphatase (lysosomes and endoplasmic reticulum) was increased by three of four doses, 5'-nucleotidase and alkaline phosphatase (plasma membrane) were increased 4-fold, neutral-alpha-glucosidase (endoplasmic reticulum) and malate dehydrogenase (mitochondria) were unchanged, and catalase (peroxisomes) was significantly increased. Bromocriptine (500 micrograms) administration to lactating and postlactating rats for 12 and 24 h significantly decreased the pituitary DNA but not the total protein content of the pituitaries in all animals. The lysosomal acid PRL proteolytic activity and the lysosomal enzyme activities, N-acetyl-beta-glucosaminidase and beta-glucuronidase, were increased by suckling withdrawal alone. Acid PRL proteolytic activity was further increased (to 18-fold) by coadministration of bromocriptine, whereas the increase in the activities of the other lysosomal marker enzymes was blocked. Malate dehydrogenase activity (mitochondria) was also increased by litter removal and blocked by bromocriptine. The activity of the plasma membrane markers 5'-nucleotidase and alkaline phosphatase were increased by litter removal, and bromocriptine further increased both enzyme activities. The activity of neutral-alpha-glucosidase (endoplasmic reticulum) was unchanged by any treatment. The results demonstrate that bromocriptine produces significant changes in the activities of lysosomal marker enzymes, particularly acid PRL proteolytic activity, as well as marker enzymes of plasma membranes and other organelles in pituitaries of lactating and postlactating rats.
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PMID:Effects of bromocriptine on pituitary organelle marker enzyme activities in lactating and postlactating rats: selective activation of lysosomal prolactin proteolytic activity. 608 93

We examined the effects of hypophysectomy and pituitary hormone replacement on vitamin D-dependent calcium-binding protein (CaBP) in rat small intestine. The concentration of immunoreactive CaBP per mg intestinal protein was decreased by at least 56% in hypophysectomized rats compared to that in intact pair-fed controls. Alkaline phosphatase and total protein also were reduced by hypophysectomy, but pair-feeding produced comparable decreases. Daily injections of 2, 10, or 50 micrograms human GH (hGH) for 9 days produced a dose-dependent increase in CaBP. At the highest hGH dose (50 micrograms), the content of CaBP was increased 2- to 4-fold to intact levels. By comparison, the increases in total protein and alkaline phosphatase were small (25% to 40% and 80% to 90%, respectively). The induction of CaBP preceded the other protein responses; half-maximal increases in CaBP occurred after 2 days of hGH (50 micrograms/day) treatment before statistically significant changes in total protein or alkaline phosphatase activity. hGH was the most potent pituitary hormone tested; ovine TSH (25 mU/day) had no effect on CaBP, and ovine PRL (10 or 50 micrograms/day) increased CaBP by only 25-27% (P = 0.014). These studies indicate that the vitamin D-dependent intestinal CaBP in hypophysectomized rats is regulated by GH and provide further evidence that the pituitary may be involved in regulating vitamin D-dependent intestinal adaptations.
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PMID:Human growth hormone increases intestinal vitamin D-dependent calcium-binding protein in hypophysectomized rats. 661 74

Serum 1,25-dihydroxyvitamin D, parathyroid hormone, calcium, phosphorus and alkaline phosphatase levels as well as the renal handling of phosphorus were measured in female patients with hyperprolactinemia. Despite elevated prolactin levels, none of the patients showed an imbalance of the biochemical parameters of mineral homeostasis. Neither surgery nor bromocriptine treatment, both of which brought PRL within the normal limits, had an appreciable effect on the circulating concentrations of mineral and calciotropic hormones. These results do not allow us to assign a definite role to PRL in the control of mineral metabolism in man.
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PMID:Effects of hyperprolactinemia on calciotropic hormones. 723 Sep 13

Phosphorylation is a mechanism by which cells regulate structure and function of proteins. We have previously demonstrated in vivo synthesis and secretion of phosphorylated bovine prolactin (bPRL) from the pituitary, and have isolated and partially characterized the phosphorylated bPRL. In order to investigate the structure/function role of phosphorylation on the biological activity of bPRL, we compared the activities of nonphosphorylated and phosphorylated bPRL isolated from pituitaries, with bPRL provided by the NIDDK (NIDDK-bPRL) to stimulate Nb2 cell proliferation. Nonphosphorylated bPRL has activity similar to, although slightly lower than that of NIDDK bPRL (ED50 = 7.03 pM and 22.8 pM, respectively). The activity of phosphorylated bPRL is significantly reduced (ED50 = 1066 pM). Using Nb2 lymphoma cell homogenate, NIDDK and nonphosphorylated bPRLs are equally effective in competitive receptor binding assays (Kd = 0.252 and 0.269 nM, respectively). Phosphorylated bPRL does not compete for the PRL receptor at concentrations up to 65 nM. Following enzymatic removal of the phosphate group using alkaline phosphatase, there is an increase in the biological activity of phosphorylated bPRL (ED50 = 73.3 pM) while the activity of nonphosphorylated BPRL remained unchanged following enzyme treatment (21.4 pM). We conclude that (1) structural changes induced by phosphorylation of bPRL are responsible for loss of bioactivity, (2) dephosphorylation of phosphorylated bPRL restores biological activity, and (3) the reduction in biological activity of phosphorylated bPRL is mediated by a decrease in receptor binding.
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PMID:Biological activity of phosphorylated and dephosphorylated bovine prolactin. 748 26

Interleukin-1 alpha (IL-1 alpha) and IL-1 beta bind to either the p80 type I IL-1 receptor (IL-1RI) or the p68 type II IL-1R (IL-1RII) on both T and B lymphocytes. We and others have previously shown that the anterior pituitary gland also has specific high affinity binding sites for IL-1 alpha (Kd = approximately 1 nM) and expresses transcripts for both isoforms of the IL-1R. However, the identity of cells in the anterior pituitary gland that express the IL-1R and whether different populations of adenohypophyseal cells express different isoforms of the IL-1R remain unknown. Here we have used a combination of immunohistochemistry and histochemistry to localize IL-1RI and IL-1RII to specific target cells in the mouse anterior pituitary gland. Perfusion-fixed, paraffin-embedded sections of anterior pituitary gland were immunolabeled with well characterized monoclonal antibodies to either IL-1RI or IL-1RII and counterstained using a modified Gomori's method to document acidophils and basophils. Immunolabeling demonstrated that both IL-1RI and IL-1RII were abundantly expressed on a single population of anterior pituitary gland cells and that these cells could be classified on the basis of histochemical staining as a subpopulation of acidophils. The distribution, morphology, and proportion of cells immunolabeled for IL-1RI and IL-1RII were consistent with GH-synthesizing cells. To confirm this hypothesis, a modified indirect avidin-biotin complex, sequential peroxidase/alkaline phosphatase technique was used to label anterior pituitary gland cells with antibodies to IL-1RI followed by antibodies to IL-1RII, GH, PRL, or ACTH. The IL-1RI-positive cells predominately coexpressed IL-1RII and GH, but very little, if any, PRL or ACTH. These data establish that the predominant cell population in the murine anterior pituitary gland that constitutively expresses IL-1R stain as acidophils histochemically, is round to oval with dense granular cytoplasm and eccentric nuclei, synthesizes GH, and simultaneously expresses IL-1RI and IL-1RII isoforms.
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PMID:Dual expression of p80 type I and p68 type II interleukin-I receptors on anterior pituitary cells synthesizing growth hormone. 875 80


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