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Keri G, Parameswaran V, Trunkey DD, Ramachandran J. Effects of septic shock plasma on adrenocortical cell function. Life Sci 1981; 28:1917-23. [PMID: 6265722 DOI: 10.1016/0024-3205(81)90299-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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152
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Cheitlin R, Ramachandran J. Regulation of actin in rat adrenocortical cells by corticotropin. J Biol Chem 1981; 256:3156-8. [PMID: 6259151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Corticotropin (ACTH) induces a characteristic retraction of rat adrenocortical cells in culture. Densitometric analysis of sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels of cell lysates showed that ACTH induced a 20% decrease in actin content. These results were fully confirmed by quantitation of actin by the DNase 1 inhibition assay. The decrease in actin is hormone-specific, concentration-dependent, and correlates temporally with the morphological change induced by ACTH. The change in actin content and the reorganization of microfilament ultrastructure may together mediate hormone regulation of cell shape at the cytoskeletal level.
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153
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Buckley DI, Houghten RA, Ramachandran J. Isolation of alpha-melanotropin and N, O-diacetylserine1-alpha-melanotropin from porcine pituitary extracts. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1981; 17:508-13. [PMID: 7309355 DOI: 10.1111/j.1399-3011.1981.tb02021.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In the course of isolation of alpha-melanotropin (alpha-MSH) from porcine pituitary extracts, a peptide with identical amino acid composition but slightly less polar properties compared to alpha-MSH was detected and isolated by partition chromatography. The new peptide was identified as N, O-diacetyl-Ser1-alpha-MSH by high resolution nuclear magnetic resonance spectroscopy. N, O-diacetyl-Ser1-alpha-MSH was readily converted to alpha-MSH by incubation at pH 9.5. The O-acetyl analog of alpha-MSH was found to be as active as alpha-MSH in stimulating lipolysis in isolated rabbit adipocytes.
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154
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Cheitlin R, Ramachandran J. Regulation of actin in rat adrenocortical cells by corticotropin. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69580-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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155
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Buckley DI, Ramachandran J. Preparation of tritiated alpha-melanotropin with high specific radioactivity. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1981; 17:514-8. [PMID: 7309356 DOI: 10.1111/j.1399-3011.1981.tb02022.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
alpha-Melanotropin (alpha-MSH) was iodinated and 3,5-diiodotyr2-alpha-MSH was isolated by reverse phase high performance liquid chromatography (HPLC). Catalytic dehalogenation of the diiodo derivative in the presence of tritium resulted in the formation of 3,5-ditritiotyr2-alpha-MSH. The tritiated peptide was purified by ion exchange and partition chromatography. The radioactive peptide was found to be homogeneous and identical to alpha-MSH by paper electrophoresis and HPLC. The tritiated alpha-MSH stimulated lipolysis in rabbit adipocytes nearly as well as alpha-MSH. The specific radioactivity of tritiated alpha-MSH was 42 Ci/mmol or 73% of the theoretical value.
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156
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Behrens CM, Ramachandran J. The effect of glucocorticoids on adipocyte corticotropin receptors and adipocyte responses. BIOCHIMICA ET BIOPHYSICA ACTA 1981; 672:268-79. [PMID: 6260229 DOI: 10.1016/0304-4165(81)90293-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A specific and sensitive assay for determining the binding of adrenocorticotropin (ACTH) to isolated rat adipocytes has been developed and utilized to study the effect of glucocorticoids on ACTH receptor. Measurement of the binding of tritiated ACTH (spec. act. 90 Ci/mmol) to adipocytes isolated from normal, adrenalectomized, and adrenalectomized dexamethasone-treated rats indicated that there are no differences among these three populations in either the magnitude or the affinity of the binding reaction. The binding interaction was found to be of high affinity (Kd = 5.23 + 1.92 . 10(-9) M and paralleled closely the stimulation of lipolysis (Km = 2.09 +/- 0.35 . 10(-9) M. About 16,300 receptors were calculated to be presented per adipocyte. Hormone-induced cyclic 3',5'-adenosine monophosphate production remained intact after adrenalectomy, thereby confirming that receptors are not lost during steroid deprivation. The lipolytic response did, however, become less sensitive to both ACTH and epinephrine following adrenalectomy. Pre-treatment of adrenalectomized rats with dexamethasone resulted in an increase in basal and hormone-stimulated levels of cyclic AMP and glycerol production to super-normal values. In adipocyte ghost preparations, ACTH and epinephrine sensitive adenylate cyclase activity was not decreased by adrenalectomy and dexamethasone administration did not result in a selective enhancement of ACTH sensitive adenylate cyclase activity. Our results indicate that glucocorticoids do not cause their permissive effects by specific regulation of the ACTH receptor on the adipocyte.
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157
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Srinivas K, Valmikinathan K, Ramachandran J, Saravanan PK, Ramanujam ND. The importance of CSF electrophoresis in SSPE. THE JOURNAL OF THE ASSOCIATION OF PHYSICIANS OF INDIA 1981; 29:81-2. [PMID: 7263595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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158
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Gondos B, Rao A, Ramachandran J. Effects of antiserum to luteinizing hormone on the structure and function of rat Leydig cells. J Endocrinol 1980; 87:265-70. [PMID: 7430922 DOI: 10.1677/joe.0.0870265] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The influence of LH on morphology and function of Leydig cells was investigated in adult rats by selective neutralization of endogenous hormone with specific antibodies. Administration of antiserum to LH to mature male Sprague-Dawley rats for 8 days caused a significant decrease in testis weight and levels of testosterone in serum but had no effect on the overall number of interstitial cells per testis. The ability of interstitial cells isolated from antiserum-treated animals to produce testosterone in response to exogenous LH was also significantly lower than that of cells derived from animals treated with normal rabbit serum. Although the number of interstitial cells was similar in the treated and control groups, morphological studies indicated a major decrease in the number of fully differentiated Leydig cells in the antiserum-treated animals. Furthermore, neutralization of LH with antiserum resulted in disruption of the endoplasmic reticulum and accumulation of dense bodies resembling lysosomes in the Leydig cells. These results suggested that the primary trophic action of LH is to induce and maintain the steroidogenic capacity of the Leydig cells.
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159
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Canova-Davis E, Ramachandran J. Photoreactive derivatives of corticotropin. 1. Preparation and chracterization of 2,4-dinitro-5-azidophenylsulfenyl derivative of corticotropin. Biochemistry 1980; 19:3275-80. [PMID: 6250560 DOI: 10.1021/bi00555a027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A photoaffinity probe for corticotropin (ACTH) receptors was prepared by selective modification of the single tryptophan residue in ACTH. A new photoreactive agent, 2,4-dinitro-5-azidophenylsulfenyl chloride, was synthesized and used for introducing the photoreactive group into ACTH. 2,4-Dinitro-5-azidophenylsulfenyl-Trp9-ACTH (DNAPS-ACTH) was also prepared by thiolysis of 2,4-dinitrophenyl-sulfenyl-Trp9-ACTH to form 2-thiol-Trp9-ACTH and reaction of this with 2,4-dinitro-5-azidofluorobenzene. DNAPS-ACTH was characterized by ultraviolet spectra, peptide mapping, and amino acid analysis. Covalent attachment of DNAPS-ACTH to a pituitary protein fraction FI by photolysis was demonstrated by ultraviolet absorption changes as well as by the use of tritiated DNAPS-ACTH.
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160
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Muramoto K, Ramachandran J. Photoreactive derivatives of corticotropin. 2. Preparation and characterization of 2-nitro-4(5)-azidophenylsulfenyl derivatives of corticotropin. Biochemistry 1980; 19:3280-6. [PMID: 6250561 DOI: 10.1021/bi00555a028] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Two new photoreactive arylsulfenyl chlorides, 2-nitro-4-azidophenylsulfenyl chloride (2,4-NAPS-Cl) and 2-nitro-5-azidophenylsulfenyl chloride (2,5-NAPS-Cl), have been synthesized and used for the selective modification of corticotropin (ACTH). Both reagents reacted rapidly with N-acetyltryptophanamide and ACTH under acidic conditions. The NAPS derivatives of ACTH were purified by partition chromatography and characterized by absorption spectra, amino acid analysis, and peptide mapping. The spectral changes caused by photolysis as well as the kinetics of photolysis are described. Tritiated 2,5-NAPS-ACTH was attached covalently to a pituitary protein fraction FI by photolysis. The photolabeling of FI was blocked in the presence of excess ACTH.
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161
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McPherson MA, Ramachandran J. Inhibition of DNA synthesis in adrenocortical cells by cytochalasin B. J Cell Biol 1980; 86:129-34. [PMID: 6252210 PMCID: PMC2110659 DOI: 10.1083/jcb.86.1.129] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
ACTH inhibits DNA synthesis in normal rat and mouse tumor Y-1 adrenocortical cells within the same concentration range that it stimulates steroidogenesis. These processes can be independently regulated as demonstrated by the divergent actions of cytochalasin B on these cells. In the normal cells, cytochalasin B does not increase steroidogenesis in serum-free or serum-containing media, and it decreases the stimulation produced by ACTH. In the absence of serum, the Y-1 cells respond in a similar way. However, in serum-containing media, cytochalasin B increases steroidogenesis in these cells and does not inhibit the response to ACTH. In both cell types, cytochalasin B inhibits [3H]thymidine incorporation into DNA by a mechanism different than that of ACTH. In the Y-1 cells, this inhibition is caused by a decreased uptake of [3H]thymidine into the cell, which probably reflects a decreased transport across the cell membrane. In the normal cells, cytochalasin B, like ACTH, does not affect [3H]thymidine transport, but it decreases DNA synthesis much more rapidly than does ACTH. This inhibition may be the result of the disruption of microfilaments by cytochalasinB, because our evidence indicates that it is not caused by a decrease in glucose uptake by the cells.
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162
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Ramachandran J, Muramoto K, Kenez-Keri M, Keri G, Buckley DI. Photoaffinity labeling of corticotropin receptors. Proc Natl Acad Sci U S A 1980; 77:3967-70. [PMID: 6254005 PMCID: PMC349748 DOI: 10.1073/pnas.77.7.3967] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A photoaffinity label for corticotropin (ACTH) receptors was prepared by selective chemical modification of the single tryptophan residue in the hormone by reaction with 2-nitro-5-azidophenylsulfenyl chloride. The photoreactive derivative, [(2-nitro-5-azidophenylsulfenyl)-Trp9]ACTH (2,5-NAPS-ACTH), stimulated corticosterone synthesis to 60% of the maximal rate induced by ACTH in isolated rat adrenocortical cells. 2.5-NAPS-ACTH caused only a marginal stimulation of cyclic AMP production compared to the unmodified hormone. Stimulation of corticosterone production and cyclic AMP accumulation induced by ACTH were both inhibited in a competitive manner by 2,5-NAPS-ACTH. Photolysis of adrenocortical cells in the presence of 2,5-NAPS-ACTH resulted in a 40% inactivation of ACTH receptors mediating steroidogenesis, as shown by the decrease in response to subsequent stimulation with ACTH. No loss of function was observed when photolysis was conducted in the presence of the photoresistant analog [(2,4-dinitrophenylsulfenyl)-Trp9]ACTH. Covalent attachment of the hormone to the receptors was also demonstrated by photolyzing adrenocortical cells in the presence of tritiated 2,5-NAPS-ACTH of high specific radioactivity (90 Ci/mmol) and analyzing the cell proteins by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. A protein with an approximate molecular weight of 100,000 was specifically labeled by this procedure. The unique labeling of an adrenocortical cell protein and the concomitant loss of ACTH responsiveness suggest that physiologically relevant receptors are photolabeled by this method.
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163
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McPherson MA, Ramachandran J. Corticotropin stimulates cyclic nucleotide independent protein kinase activity of intact adrenocortical cells. Biochem Biophys Res Commun 1980; 94:1057-65. [PMID: 6249296 DOI: 10.1016/0006-291x(80)90526-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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164
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Lee CY, McPherson M, Licko V, Ramachandran J. Pituitary corticotropin-inhibiting peptide: properties and use in study of corticotropin action. Arch Biochem Biophys 1980; 201:411-9. [PMID: 6249206 DOI: 10.1016/0003-9861(80)90529-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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165
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Rao AJ, Behrens C, Ramachandran J. Immunochemical studies of adrenocorticotropin using tritium labeled hormone. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1980; 15:480-4. [PMID: 6254894 DOI: 10.1111/j.1399-3011.1980.tb02925.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A radioimmunoassay using specifically tritiated corticotropin (3H-ACTH) of high specific radioactivity (46 Ci/mmol) and full biological activity has been developed. The assay is sensitive to ACTH in the range 200 pg-10 ng. 50% displacement of 3H-ACTH is produced by less than a twofold excess of unlabeled hormone. Immunochemical studies with various ACTH analogs showed that the antiserum recognized the intact molecule better than any of other fragments.
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166
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Rae PA, Zinman H, Ramachandran J, Schimmer BP. Responses of Y1 adrenocortical tumor cells to o-nitrophenyl sulfenyl ACTH. Mol Cell Endocrinol 1980; 17:171-9. [PMID: 6245980 DOI: 10.1016/0303-7207(80)90111-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
NPS(o-nitrophenyl sulfenyl)-ACTH stimulated steroidogenesis in Y1 cells to the same maximum level as did ACTH, but with a 60-fold lower potency than the native hormone. NPS-ACTH also stimulated the extracellular accumulation of cAMP in Y1 cells with lower potency than the unmodified hormone. The amount of cAMP accumulated in the presence of NPS-ACTH approached 75% of the maximum with ACTH. In Y1 plasma membranes, NPS-ACTH was a partial agonist of adenylate cyclase activity, witn an efficacy dependent upon the type of guanyl nucleotide present. The steroidogenic responses of two Y1(Kin) mutants and two Y1(Cyc) mutants to NPS-ACTH paralleled their responses to ACTH and reflected closely their defects in cAMP-dependent protein kinase and ACTH-sensitive adenylate cyclase activity. These data imply an obligatory role for adenylate cyclase and cAMP-dependent protein kinase activities in stimulation of steroidogenesis in Y1 cells by NPA-ACTH.
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167
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Tabakoff W, Hamed A, Ramachandran J. Study of Metals Erosion in High Temperature Coal Gas Streams. ACTA ACUST UNITED AC 1980. [DOI: 10.1115/1.3230213] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In order to provide the basis for alloy selection in future turbines using pulverized coal, an investigation is undertaken to obtain a basic understanding of the mechanisms of erosion at high temperatures. The test equipment has been designed to simulate the aerodynamic and thermodynamic conditions in the turbine. This facility has the capability of providing between ambient and a 1093°C (2000°F) environment temperature for erosion testing of various materials. The effects of high temperature on the erosion rate was determined and the test results from 304 stainless steel alloy are presented.
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168
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Llanos AJ, Ramachandran J, Creasy RK, Rudolph AM, Serón-Ferré M. alpha-Melanocyte-stimulating hormone and adrenocorticotropin in the regulation of glucocorticoid secretion during the perinatal period in sheep. Endocrinology 1979; 105:613-7. [PMID: 223827 DOI: 10.1210/endo-105-3-613] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
To determine the role of other ACTH-like peptides in the regulation of glucocorticoid secretion in fetal sheep, we examined the responses of the adrenal gland of fetal and newborn sheep to comparable single doses of alpha MSH (75 micrograms) or ACTH (50 micrograms) during the last third of gestation and the first month of postnatal life. alpha MSH first increased the plasma glucocorticoid concentration at 121--130 days of gestation [from 16 +/- 1.5 to 36.9 +/- 9 (SE) ng/ml]; the response to alpha MSH persisted on days 131--140 of gestation and during the first month after birth. ACTH first increased the plasma glucocorticoid concentration at 131--140 days of gestation and increased it further in the first month after birth (from 18.9 +/- 3.6 to 97.0 +/- 10 ng/ml). The observations that the adrenal glands of fetuses and newborn lambs responded to alpha MSH at a dose comparable to that of ACTH and that the response to alpha MSH in the fetus preceded the response to ACTH may indicate that adrenal receptors mature during fetal development. These data also suggest that the regulation of the adrenal during fetal life may involve more than one tropic hormone.
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169
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Kawauchi H, Muramoto K, Ramachandran J. Isolation and primary structure of adrenocorticotropin from several species of whale. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1978; 12:318-24. [PMID: 217846 DOI: 10.1111/j.1399-3011.1978.tb02903.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The isolation of adrenocorticotropin (ACTH) from fin (Balaenoptera physalus), sei (Blaenoptera borelis) and sperm (Physeter catodon) whale pituitaries is described. Their primary structures have been elucidated by the fluorescein isothiocyanate method and revealed to be identical to the structure of the human hormone. Fin whale exhibited an identical steroidogenic activity to that of the porcine hormone.
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170
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Rao AJ, Long JA, Ramachandran J. Effects of antiserum to adrenocorticotropin on adrenal growth and function. Endocrinology 1978; 102:371-8. [PMID: 217590 DOI: 10.1210/endo-102-2-371] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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171
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Papkoff H, Bewley TA, Ramachandran J. Physicochemical and biological characterizations of pregnant mare serum gonadotropin and its subunits. BIOCHIMICA ET BIOPHYSICA ACTA 1978; 532:185-94. [PMID: 413583 DOI: 10.1016/0005-2795(78)90462-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Pregnant mare serum gonadotropin and its subunits have been further characterized. Ultracentrifugation of the gonadotropin at pH 1.3 and 11.5 showed little evidence of dissociation compared to pH 8.2. Highly purified subunits are obtained by urea dissociation and ion-exchange chromatography followed by gel-filtration. Circular dichroism spectra of the gonadotropin and its subunits are much like those of ovine lutropin and its subunits in that there is little evidence for secondary structure and one or more tyrosine residues are inaccessible in the intact gonadotropin compared to the subunits. The alpha-subunit possesses almost 3 times as much total carbohydrate as the beta-subunit; the individual sugar composition of each was determined as well as the amino acid composition. The alpha-subunit begins with the sequence NH2-Phe-Pro (Gly or Pro) ... and terminates with isoleucine. The beta-subunit has the sequence NH2-Ser-Pro-Gly ...; no C-terminal residue is detectable by either carboxypeptidase or hydrazinolysis. Biological studies show the gonadotropin to be active in assays specific for both lutropin and follitropin. Precipitin test in agar with rabbit antiserum against the gonadotropin show that the beta subunit cross-reacts whereas the alpha subunit does not.
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172
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Liles S, Ramachandran J. Regulation of delta 5-3 beta-hydroxysteroid dehydrogenase-isomerase activity in adrenocortical cell cultures by adrenocorticotropin. Biochem Biophys Res Commun 1977; 79:226-33. [PMID: 200239 DOI: 10.1016/0006-291x(77)90084-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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173
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174
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Suyama AT, Long JA, Ramachandran J. Ultrastructural changes induced by ACTH in normal adrenocortical cells in culture. J Biophys Biochem Cytol 1977; 72:757-63. [PMID: 190242 PMCID: PMC2111036 DOI: 10.1083/jcb.72.3.757] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The effects of ACTH, its o-nitrophenyl sulfenyl derivative (NPS-ACTH) and dibutyryl cyclic AMP (dbc AMP) on the ultrastructural morphology of adrenocortical cells of adult rats in monolayer culture have been investigated. NPS-ACTH, which has previously been shown to stimulate steroidogenesis but not cAMP synthesis in adrenal cells, induced the same characteristic transformation of mitochondrial architecture as produced by ACTH or high concentrations of dbcAMP. All three agents caused the disappearance of electron-opaque granules present in the mitochondria of unstimulated cells. It was found that these granules could be extracted with EGTA (ethylene glycol-bis(beta-aminoethyl ether) N,N,N',N'-tetraacetate). These results are discussed in the light of the known importance of calcium ions in the actions of ACTH.
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175
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Ramachandran J, Behrens C. Preparation and characterization of specifically tritiated adrenocorticotropin. Biochim Biophys Acta Gen Subj 1977; 496:321-8. [PMID: 189837 DOI: 10.1016/0304-4165(77)90314-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The catalytic dehalogenation of iodinated derivatives of corticotropin in the presence of tritium was investigated. In 0.1 M acetic acid, complete and rapid removal of iodine was achieved in the presence of freshly prepared palladium or palladium oxide as catalyst, but the specific radioactivity of the product was only 10-20% of the theoretically attainable value. Synthetic human corticotropin containing a 3,5-diiodo tyrosine in position 23 in place of tyrosine was successfully dehalogenated in solvent mixture 0.1 M acetic acid: hexamethylphosphoramide: dimethylformamide (1 : 10 : 90, v/v) in the presence of palladium oxide and calcium carbonate. The product was obtained in 30% yield after purification by carboxymethyl cellulose chromatography. The tritiated hormone had a specific radioactivity of 46 Ci/mmol (80% of the theoretical value) and was as potent as synthetic human corticotropin in stimulating steroidogenesis and lipolysis.
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176
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Ramachandran J, Kong YC, Liles S. Effects of ACTH and its O-nitrophenyl sulphenyl derivative on adrenocortical function in vivo. Eur J Endocrinol 1976; 82:587-99. [PMID: 180742 DOI: 10.1530/acta.0.0820587] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Both ACTH and NPS-ACTH in which the single tryptophan residue of the hormone is modified were able to stimulate adrenal corticosterone concentration to the same extent in hypophysectomized rats, although a higher dose of NPS-ACTH was required. ACTH stimulated adrenal cyclic AMP levels 120-fold in hypophysectomized rats whereas NPS-ACTH caused a marginal increase. In the case of ACTH, low doses of the hormone capable of producing maximal stimulation of corticosterone synthesis did not produce any detectable change in cyclic AMP concentration. The rates of secretion of corticosterone induced by ACTH and NPS-ACTH in vivo were the same. NPS-ACTH was found to be 1.2% as potent as ACTH. The role of cyclic AMP in adrenal repair was investigated by administering equipotent doses of ACTH or NPS-ACTH to hypophysectomized rats. In adult rats both failed to produce a significant increase in adrenal weight. Adrenal function (measured by responsiveness to exogenous ACTH in vitro) was restored by NPS-ACTH but not to the same degree as ACTH. In hypophysectomized weanling rats, ACTH produced a small but significant increase in adrenal weight but NPS-ACTH did not. These results suggest that an increase in adrenal cyclic AMP may not be obligatory for the stimulation of steroidogenesis by ACTH and that some of the trophic actions of the hormone may be mediated by cyclic AMP.
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177
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Ramachandran J, Lee V. Divergent effects of adrenocorticotropin and melanotropin on isolated rat and rabbit adipocytes. Biochim Biophys Acta Gen Subj 1976; 428:339-46. [PMID: 179569 DOI: 10.1016/0304-4165(76)90041-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The stimulation of lipolysis in isolated rat and rabbit fat cells by adrenocorticotropin (ACTH) and alpha-melanotropin has been studied. The concentration of alpha-melanotropin required for half maximal stimulation is 0.23 times that of ACTH in rabbit adipocytes but as high as 1140 times that of ACTH in rat fat cells. Chemical modification of the tryptophan residue in ACTH and melanotropin resulted in a loss of lipolytic activity in rat adipocytes and an increase in lipolytic potency in rabbit fat cells. These differences between rat and rabbit fat cells were evident when stimulation of cyclic AMP synthesis was measured in isolated cells or ghosts. The results are discussed in terms of the difference in the hormone receptors of the fat cells of the two species.
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Ramachandran J, Farmer SW, Liles S, Li CH. Comparison of the steroidogenic and melanotropic activities of corticotropin, alpha-melanotropin and analogs with their lipolytic activities in rat and rabbit adipocytes. Biochim Biophys Acta Gen Subj 1976; 428:347-54. [PMID: 179570 DOI: 10.1016/0304-4165(76)90042-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ability of alpha-melanotropin and a series of synthetic peptides related to adrenocorticotropin (ACTH) to stimulate steroidogenesis in isolated rat adrenal cells, melanin dispersion in frog melanophores and lipolysis in rat and rabbit fat cells have been studied. It was found that the steroidogenic activity closely paralleled the lipolytic activity of these peptides in rat fat cells, whereas the melanocyte stimulating activity paralleled the lipolytic activity in rabbit fat cells. These results indicate that the structural requirements for stimulating steroidogenesis in isolated rat adrenal cells and lipolysis in isolated rat fat cells are quite similar. The structural features required for eliciting lipolysis in rabbit fat cells appear to be very similar to those necessary for stimulating frog melanophores. The possibility that regulation of lipid metabolism in the rabbit may be a new function acquired by melanotropin is discussed.
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179
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Canova-Davis E, Ramachandran J. Chemical modification of the tryptophan residue in adrenocorticotropin. Biochemistry 1976; 15:921-7. [PMID: 174723 DOI: 10.1021/bi00649a030] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The single tryptophan residue in the pituitary hormone adrenocorticotropin was modified selectively by reaction with a variety of substituted o-nitrophenylsulfenyl chlorides. In addition to quantitative modification of the tryptophan residue, the reaction invariably resulted in partial oxidation of the methionine residue to the sulfoxide. The methionine sulfoxide derivative could be separated from the desired product by partition chromatography on Sephadex G-50 in the solvent system 1-butanol-pyridine-0.1% acetic acid (5:3:11). Thus, the 2,4-dinitrophenylsulfenyl, 2-nitro-4-carboxyphenylsulfenyl, and 2-nitro-4-carbamidophenylsulfenyl derivatives of adrenocorticotropin were prepared and characterized. Modifications in the isolation of adrenocorticotropin from ovine pituitaries are also described. The melanocyte stimulating activities of the native hormone and the analogues are discussed.
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180
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Rao AJ, Ramachandran J, Li CH. Human pituitary growth hormone. 44. Effects of plasmin-modified hormone and its fragments on ornithine decarboxylase activity and lipolysis. Exp Biol Med (Maywood) 1976; 151:285-7. [PMID: 129786 DOI: 10.3181/00379727-151-39193] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The rat hepatic ornithine decarboxylase stimulating activity of plasmin-modified human growth hormone and its two peptide fragments has been investigated. The activity was completely retained after plasmin treatment. The NH2-terminal fragment [Cys (Cam)53-HGH-(1-134)] retained 10% of the activity, whereas the COOH-terminal fragment [Cys (Cam) 165, 182, 189-(141-191)] was not active. The lipolytic activity of human growth hormone was greatly reduced after plasmin treatment, as examined in isolated rabbit adipocytes. It is suggested that the structural requirements for the lipolytic activity of the hormone are different from those required for stimulation of ornithine decarboxylase activity.
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181
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Kawauchi H, Bewley TA, Ramachandran J, Li CH. Human pituitary somatotropin: 46. Preparation of tritium labelled hormone. BIOCHIMICA ET BIOPHYSICA ACTA 1976; 420:214-7. [PMID: 813774 DOI: 10.1016/0005-2795(76)90359-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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182
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Rao AJ, Ramachandran J. Cyclic AMP production in isolated rat seminiferous tubule cell preparations: a potential in vitro assay for follicle stimulating hormone. Life Sci 1975; 17:411-6. [PMID: 169451 DOI: 10.1016/0024-3205(75)90491-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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183
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Lee V, Ramachandran J, Li CH. Human pituitary growth hormone. Intrinsic lipolytic activity on rabbit fat cells. Arch Biochem Biophys 1975; 169:669-77. [PMID: 170868 DOI: 10.1016/0003-9861(75)90211-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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184
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Ramachandran J, Sairam MR. The effects of interstitial cell-stimulating hormone, its subunits, and recombinants on isolated rat Leydig cells. Arch Biochem Biophys 1975; 167:294-300. [PMID: 165777 DOI: 10.1016/0003-9861(75)90465-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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185
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Ramachandran J, Suyama AT. Inhibition of replication of normal adrenocortical cells in culture by adrenocorticotropin. Proc Natl Acad Sci U S A 1975; 72:113-7. [PMID: 164010 PMCID: PMC432251 DOI: 10.1073/pnas.72.1.113] [Citation(s) in RCA: 89] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Adrenocorticotropic hormone (ACTH) inhibited [3H]thymidine incorporation in normal adrenocortical cells of adult rats in culture, with a concomitant increase in corticosterone production and a characteristic retraction of cells. Both dibutyryl cyclic AMP and an analog of ACTH, which produces virtually no cyclic AMP, inhibited DNA synthesis and stimulated steroid production. ACTH inhibited the proliferation of adrenocortical cells obtained from suckling rats as well as the cells obtained from the capsular tissue of adult rat adrenal glands, whereas insulin caused a stimulation of DNA synthesis. These results suggest that the major role of ACTH is to induce the transformation of the undifferentiated cells of the adrenal gland into functional fasciculata cells and that the proliferation of adrenocortical cells may be under control of factors other than ACTH.
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186
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Ramachandran J. Nonlinear vibrations of elastically restrained rectangular orthotropic plates. NUCLEAR ENGINEERING AND DESIGN 1974. [DOI: 10.1016/0029-5493(74)90224-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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187
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188
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Moyle WR, Ramachandran J. Effect of LH on steroidogenesis and cyclic AMP accumulation in rat Leydig cell preparations and mouse tumor Leydig cells. Endocrinology 1973; 93:127-34. [PMID: 4351309 DOI: 10.1210/endo-93-1-127] [Citation(s) in RCA: 146] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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189
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Moyle WR, Kong YC, Ramachandran J. Steroidogenesis and cyclic adenosine 3',5'-monophosphate accumulation in rat adrenal cells. Divergent effects of adrenocorticotropin and its o-nitrophenyl sulfenyl derivative. J Biol Chem 1973; 248:2409-17. [PMID: 4349038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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190
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Kong YC, Moyle WR, Ramachandran J. Inhibition of ACTH induced cyclic AMP synthesis in isolated rat adrenal cells by NPS-ACTH. PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE. SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE (NEW YORK, N.Y.) 1972; 141:350-2. [PMID: 4343195 DOI: 10.3181/00379727-141-36774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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191
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192
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Ramachandran J, Lee V, Li CH. Stimulation of lipolysis and cyclic AMP accumulation in rabbit fat cells by human growth hormone. Biochem Biophys Res Commun 1972; 48:274-9. [PMID: 4339625 DOI: 10.1016/s0006-291x(72)80046-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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193
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Ramachandran J, Berger A, Katchalski E. Synthesis and physicochemical properties in aqueous solution of the sequential polypeptide poly(Tyr-Ala-Glu). Biopolymers 1971; 10:1829-51. [PMID: 5110911 DOI: 10.1002/bip.360101007] [Citation(s) in RCA: 50] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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194
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Ramachandran J. A new simple method for separation of adenosine 3',5'-cyclic monophosphate from other nucleotides and its use in the assay of adenyl cyclase. Anal Biochem 1971; 43:227-39. [PMID: 4331761 DOI: 10.1016/0003-2697(71)90128-x] [Citation(s) in RCA: 213] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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195
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Schechter B, Schechter I, Ramachandran J, Conway-Jacobs A, Sela M. The synthesis and circular dichroism of a series of peptides possessing the structure (L-tyrosyl-L-alanyl-L-glutamyl)n. EUROPEAN JOURNAL OF BIOCHEMISTRY 1971; 20:301-8. [PMID: 5581321 DOI: 10.1111/j.1432-1033.1971.tb01394.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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196
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Schechter B, Schechter I, Ramachandran J, Conway-Jacobs A, Sela M, Benjamini E, Shimizu M. Synthetic antigens with sequential and conformation-dependent determinants containing the same L-tyrosyl-L-alanyl-L-glutamyl sequence. EUROPEAN JOURNAL OF BIOCHEMISTRY 1971; 20:309-20. [PMID: 4103320 DOI: 10.1111/j.1432-1033.1971.tb01395.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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197
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Ramachandran J. Melanocyte stimulating activities of the o-nitrophenyl sulfenyl derivatives of adrenocorticotropin and [5-glutamine]-alpha-melanotropin. Biochem Biophys Res Commun 1970; 41:353-7. [PMID: 4325671 DOI: 10.1016/0006-291x(70)90511-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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198
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Ramachandran J, Lee V. Divergent effects of o-nitrophenyl sulfenyl ACTH on rat and rabbit fat cell adenyl cyclases. Biochem Biophys Res Commun 1970; 41:358-66. [PMID: 4325672 DOI: 10.1016/0006-291x(70)90512-7] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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199
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Ramachandran J, Lee V. Preparation and properties of the o-nitrophenyl sulfenyl derivative of ACTH: an inhibitor of the lipolytic action of the hormone. Biochem Biophys Res Commun 1970; 38:507-12. [PMID: 4315349 DOI: 10.1016/0006-291x(70)90743-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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200
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Ramachandran J. Reaction of amino-acid esters with sodium in liquid ammonia: cleavage of the proline ring. Nature 1965; 206:927-8. [PMID: 5839847 DOI: 10.1038/206927a0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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