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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The surface topologies of mouse adrenal cortex tumor cells of primary or clonal origin grown as monolayer cell cultures were observed by scanning electron microscopy following their exposure to substances that effect steroid release and/or cell rounding. ACTH induced cell rounding with a concomitant profuse development of fine microvilli in a non-synchronously dividing cell population. This was less pronounced with other steroidogenic substances and absent in EGTA or trypsin-treated cells. Morphological alterations occurred most rapidly with cAMP and least rapidly with dbcAMP. The rapid development of fine microvilli with ACTH is proposed to be a specific hormone mediated response.
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PMID:Scanning electron microscopy of induced cell rounding of mouse adrenal cortex tumor cells in culture. 20 10

Using incubated glands, we showed that cerebral cortex and liver extracts (CCE and LE) stimulated ACTH release from neurointermediate lobe (NIL) of hypophysis as well as hypothalmus extract (HE) did. Moreover, the HE-induced ACTH release was much smaller for the NIL (1.9 X basal level) than for the anterior lobe (AL; 13.7 x basal level). Thus, under these conditions, HE seemed to have no specific effect on NIL ACTH release. Using superfused glands, we showed: (a) that both spontaneous and HE-induced ACTH release decreased during superfusion; (b) that using this system, a specific stimulatory effect on HE on NIL was observed. In contrast to HE, CCE and LE had only a small effect on NIL ACTH release (always less than 20% of that caused by HE) which could be considered as a nonspecific response; (c) that trypsin suppressed the stimulating effect on HE as well on NIL as on AL; and (d) that arginine antidiuretic hormone (ADH) was not responsible for the stimulating effect of HE on NIL ACTH release, because synthetic ADH had no effect and HE containing ADH (from normal rats) or HE containing no ADH (from Brattleboro rats or from immunoneutralization of ADH in normal HE) had the same effect. From these results, we can conclude that HE contain a peptidic factor different from ADH which is able to stimulate in vitro release of ACTH from the NIL.
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PMID:In vitro regulation of ACTH release from neurointermediate lobe of rat hypophysis. I. Effect of crude hypothalamic extracts. 20 49

The treatment of adipose tissue of the rat epidiymis with trypsin decreased the lipolytic action of ACTH by 95%, and the lipolytic action of adrenalin by 50%. Supplementation of the incubation sample with lysolecithin suspension led to a complete loss of the tissue sensitivity to ACTH and a 40% decrease in the sensitivity to adrenalin. A conclusion is made about a different structure of adrenalin and ACTH-receptors in the plasma membrane of adipose cells.
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PMID:[Differences in the structure of adrenalin and ACTH receptors in adipose cells of rats]. 23 84

We have studied the effects of the serum from a patient with an unusual form of diabetic syndrome with extreme insulin resistance on the metabolism of rat adipocytes in vitro. This serum and IgG fractions from it inhibited the [125I]insulin binding to isolated adipocytes and stimulated the 2-deoxyglucose uptake, glucose oxidation, and the incorporation of amino acids into protein. In addition, these fractions inhibited the lipolysis induced by beta 1-24 ACTH in isolated adipocytes. The insulin-like effects of this serum and the effects of insulin were not additive at their maximal concentrations. The inhibition of [125I]insulin binding was due to a decrease in receptor affinity rather than to a change in receptor number by Scatchard plot analysis. Both the inhibition of insulin binding and the insulin-like effects on rat adipocytes were neutralized by antihuman IgG. In addition, these insulin-like effects were abolished by trypsin treatment of adipocytes. These facts suggest that this serum has a circulating antibody directed at or near the insulin receptor itself and that this antibody mimics the insulin effect on rat adipocytes by binding to the insulin receptor in vitro.
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PMID:Effects of antiinsulin receptor autoantibody on the metabolism of rat adipocytes. 40 Jul 15

We have investigated the possible role of the fetal pituitary and ACTH in the control of the synthesis and post-translational processing of the enkephalin precursor, proenkephalin A (proEnk A), in the fetal sheep adrenal gland in late gestation. Fetal hypophysectomy (n = 8) or sham operations (n = 4) were performed between 109 and 118 days of gestation. At 138-139 days, either ACTH(1-24) (10.5 micrograms/0.24 ml saline per h, n = 4) was infused intravenously for 72 h into hypophysectomized fetal sheep or 0.9% (w/v) NaCl alone (0.24 ml/h, n = 4) was infused for 72 h into hypophysectomized fetal sheep and sham-operated animals. At the end of the infusion the pregnant ewe was killed and left or right adrenal glands (n = 12) were collected from the fetal sheep that were intact and given saline (Intact + sal; n = 4), hypophysectomized and given saline (Hx + sal; n = 4) and hypophysectomized and given ACTH (Hx + ACTH; n = 4). Each adrenal was homogenized in acid (acetic acid (1 mol/l)/HCl (20 mmol/l)/2-mercaptoethanol (0.2%)). After centrifugation, the supernatant was loaded onto a Sephadex G-75 column (2.0 x 50 cm), eluted at 80 ml/24 h and fractions were collected (5 ml, n = 42). An aliquot of each fraction (2 ml) was dried down prior to enzymatic digestion (trypsin/carboxypeptidase B) and oxidation with H2O2, and assay for methionine-O-enkephalin (immunoreactive Met-O-Enk).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of fetal hypophysectomy with or without ACTH replacement on the molecular weight profile of enkephalin-containing peptides in the adrenal medulla of the fetal sheep. 132 54

The time-course for the in-vitro secretion of aldosterone and 18-hydroxycorticosterone (18-OH-B) by rat adrenal whole capsular tissue (largely zona glomerulosa) was studied under control and stimulated conditions. The stimulatory effect of trypsin was relatively delayed, and the steroids were significantly enhanced only after 1 h, in contrast to the actions of ACTH, which produced effects after 15 or 30 min. Tissue-sequestered 18-hydroxydeoxycorticosterone (t-18-OH-DOC), which is not affected by ACTH, was significantly depleted by trypsin, but secreted 18-OH-DOC was not consistently affected by either stimulant. In contrast to the apparent mobilization of t-18-OH-DOC, the conversion of exogenously added [3H]18-OH-DOC to [3H]18-OH-B was inhibited by trypsin, and aldosterone was unaffected. When trilostane was added to inhibit de-novo steroidogenesis, under conditions in which the steroid secretory response to ACTH is completely inhibited, aldosterone and 18-OH-B secretion was still stimulated by trypsin although yields were lower. Compared with controls, trilostane reduced t-18-OH-DOC concentrations, and trypsin caused a further depletion. In other studies, glomerulosa plasma membrane enriched preparations were homogenized and centrifuged, and the supernatants were dialysed and added to incubations of dispersed zona glomerulosa cells in the presence or absence of stimulators of aldosterone secretion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Origin of aldosterone in trypsin-stimulated rat adrenal zona glomerulosa incubations. 133 Dec 85

Proenkephalin A (PEA) gene was found to be expressed in primary, secondary and tertiary cultures of rat fibroblasts. The 1.4 kb PEA mRNA was detected by Northern blot analysis. The same cultures do not express detectable amounts of proenkephalin B (prodynorphin) or (POMC) mRNAs. Acidic cell extracts were purified on a C18 octadecyl Amprep column and analysed with a specific methionine enkephalin radioimmunoassay to detect whether PEA mRNA is translated. A significant amount of enkephalin immunoreactivity (178-185 fmol/mg protein) was observed upon trypsin and carboxypeptidase B digestion of fibroblast cell extracts, whereas only 3-5% of this amount was free enkephalin. It is therefore indicated that the PEA mRNA expressed in fibroblasts is indeed translated to the proenkephalin precursor protein, but the cells accumulate only a small quantity of the processed pentapeptides. The implication of these observations to the possible developmental role of PEA in various non-neuronal cells, including mesodermal lineages, is discussed.
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PMID:Expression of proenkephalin A mRNA and enkephalin-containing peptides in cultured fibroblasts. 169 63

A vaccinia virus (VV) vector was used to express rat plasma kallikrein (rPK) in the constitutively secreting cells, BSC-40, and in the endocrine regulated cells, AtT-20. Using a specific rPK antibody and a fluorogenic substrate, Phe-Phe-Arg-AMC, we demonstrated that in both cell lines VV infections resulted in the synthesis of an immunoreactive enzyme predominantly present as a zymogen which can be activated with trypsin. Stimulation of VV:rPK-infected AtT-20 cells with either 5mM 8-bromo-cAMP or 56 mM KCl resulted in a different pattern of rPK and ACTH secretion, strongly suggesting that rPK follows the constitutive secretory pathway. Finally, the 10% rPK activity found within AtT-20 cell extracts had no effect on pro-opiomelanocortin (POMC) processing either intracellularly or extracellularly. The above data show that the biosynthetic machinery of both cell lines analyzed does not allow the efficient activation of plasma prekallikrein. Finally, despite the PK's demonstrated ability to cleave various hormone precursors in vitro at pairs of basic residues, in vivo, we did not obtain evidence that this hepatic enzyme can also act as an intracellular pro-protein processing enzyme.
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PMID:Expression and sorting of rat plasma kallikrein in POMC-producing AtT-20 cells. 185 25

The cellular mechanisms for aldosterone biosynthesis are incompletely understood. Although the enzymes involved are now well characterized, the dynamics of aldosterone secretion in a variety of rat adrenal preparations are not consistent with the concept that freshly synthesized corticosterone is an important intermediate. In whole glomerulosa tissue preparations, aldosterone is more readily formed from endogenous precursors than from an added radioactive precursor, such as [3H]pregnenolone, and in the in situ perfused gland preparation, aldosterone responses to stimulation, for example by ACTH, are significantly more rapid than those of corticosterone, suggesting a tissue source of steroid substrate for aldosterone production other than corticosterone. The only steroid which is stored in rat adrenal glomerulosa tissue to any extent is 18-hydroxydeoxycorticosterone (18-OH-DOC), and this pool has been located in plasma membrane fractions. It is lost on preparation of collagenase dispersed glomerulosa cells. Since dispersed glomerulosa cell preparations produce significantly less aldosterone, relative to corticosterone, than incubated intact whole glomerulosa, it is plausible that this tissue pool (which is not found in the inner zones) is the immediate precursor for aldosterone formation. Further evidence shows that trypsin, which stimulates aldosterone (and 18-hydroxycorticosterone) production in rat intact glomerulosa tissue, but not in dispersed cells, stimulates translocation of protein kinase C to the plasma membrane. It is plausible that one function of protein kinase C in the rat adrenal zona glomerulosa is to mobilize membrane sequestered 18-OH-DOC for conversion to aldosterone.
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PMID:The biosynthesis of aldosterone. 195 74

The relationship between neuroendocrine regulation and the immune system has recently become the subject of intense investigations. The pituitary secretes both immunostimulatory (growth hormone and prolactin) and immunosuppressive (ACTH) hormones, and is thus involved in the control of immune functions. The present work was aimed at the study of the immunoregulatory properties of prolactin in selected in vitro and in vivo model situations. Prolactin was found to enhance recovery of the receptor for sheep red blood cells (in vitro). Compared with control cells, incubation with prolactin and/or prolactin containing sera significantly enhanced the capacity of trypsin treated lymphocytes from the peripheral blood of healthy volunteers to form E-rosettes. Chlorpromazine stimulated prolactin release in males, and lactation stimulated prolactin release in females raised the number of large granular lymphocytes in peripheral circulation. Sera containing elevated prolactin levels stimulated the metabolic activity of peripheral neutrophilic leukocytes. These results suggest that prolactin may stimulate selective functions of cellular immunity, and that it is involved in interactions between the nervous, the hormonal and the immune systems.
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PMID:Evidence for immunomodulatory properties of prolactin in selected in vitro and in vivo situations. 207


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