scholarly journals Effect of lutropin on phosphorylation of endogenous proteins in testis Leydig cells. Correlation with testosterone production

1977 ◽  
Vol 168 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Brian A. Cooke ◽  
Monica L. Lindh ◽  
Felix H. A. Janszen
Keyword(s):  
Cyclic Amp ◽  
Leydig Cells ◽  
Sodium Dodecyl ◽  
Molecular Weights ◽  
Testosterone Production ◽  
Hypophysectomized Rats ◽  
Endogenous Proteins ◽  
Stimulation Of

The effect of lutropin on phosphorylation of endogenous proteins in testis Leydig cells was investigated, by incubating purified Leydig cells with lutropin and [32P]Pi followed by sodium dodecyl sulphate/polyacrylamide-slab gel electrophoresis of the [32P]phosphoproteins. The radioactivity of the proteins was quantified by densitometry of the radio-autograms obtained. The following results were obtained. 1. Lutropin increased the amount of32 P incorporated into three proteins (A, B and C) with apparent mol.wts. of 14300, 57000 and 77600 respectively. 2. The increase in incorporation of32P into these proteins was detectable within 5min, reaching a maximum in approx. 20min. 3. The32P incorporated into protein B (but not proteins A and C) was significantly increased with 0.1 and 1.0ng of lutropin/ml. Incorporation of32P into all three proteins was significantly increased with 10ng of lutropin/ml, reaching a maximum with 100ng/ml. 4. Testosterone production was significantly increased with 1ng of lutropin/ml, and between 10 and 1000ng/ml the degree of stimulation of testosterone production and incorporation of32P into proteins A, B and C was similar. 5. Cyclic AMP production was significantly increased with 10ng of lutropin/ml and had not reached a maximum with 1000ng/ml. 6. In Leydig cells isolated from hypophysectomized rats 3h after injection of choriogonadotropin in vivo, phosphoproteins with the same molecular weights as proteins A, B and C were found. No further increases in incorporation of32P into these proteins were obtained when lutropin was added to the Leydig cells in vitro. 7. Dibutyryl cyclic AMP (but not follitropin or testosterone) also stimulated the incorporation of32P into proteins A, B and C in Leydig cells.

EFFECTS OF ACTH AND ITS O-NITROPHENYL SULPHENYL DERIVATIVE ON ADRENOCORTICAL FUNCTION IN VIVO

1976 ◽  
Vol 82 (3) ◽  
pp. 587-599 ◽  
Author(s):  
J. Ramachandran ◽  
Y. C. Kong ◽  
Susanna Liles
Keyword(s):  
Cyclic Amp ◽  
Adrenal Weight ◽  
Adrenocortical Function ◽  
Tryptophan Residue ◽  
Adult Rats ◽  
Corticosterone Concentration ◽  
Hypophysectomized Rats ◽  
Stimulation Of

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.

scholarly journals Characterization of proteins from the cytoskeleton of Giardia lamblia

1983 ◽  
Vol 59 (1) ◽  
pp. 81-103 ◽  
Author(s):  
R. Crossley ◽  
D.V. Holberton
Keyword(s):  
Molecular Weight ◽  
Sodium Dodecyl Sulphate ◽  
Giardia Lamblia ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Gel Filtration ◽  
Molecular Size ◽  
Molecular Weights

Proteins from the axonemes and disc cytoskeleton of Giardia lamblia have been examined by sodium dodecyl sulphate/polyacrylamide gel electrophoresis. In addition to tubulin and the 30 X 10(3) molecular weight disc protein, at least 18 minor components copurify with the two major proteins in Triton-insoluble structures. The most prominent minor bands have the apparent molecular weights of 110 X 10(3), 95 X 10(3) and 81 X 10(3). Protein of 30 X 10(3) molecular weight accounts for about 20% of organelle protein on gels. In continuous 25 mM-Tris-glycine buffer it migrates mostly as a close-spaced doublet of polypeptides, which are here given the name giardins. Giardia tubulin and giardin have been purified by gel filtration chromatography in the presence of sodium dodecyl sulphate. Well-separated fractions were obtained that could be further characterized. Both proteins are heterogeneous when examined by isoelectric focusing. Five tubulin chains were detected by PAGE Blue 83 dye-binding after focusing in a broad-range ampholyte gel. Giardin is slightly less acidic than tubulin. On gels it splits into four major and four minor chains with isoelectric points in the pI range from 5.8 to 6.2. The amino acid composition of the giardin fraction has been determined, and compared to Giardia tubulin and a rat brain tubulin standard. Giardins are rich in helix-forming residues, particularly leucine. They have a low content of proline and glycine; therefore they may have extensive alpha-helical regions and be rod-shaped. As integral proteins of disc microribbons, giardins in vivo associate closely with tubulin. The properties of giardins indicate that in a number of respects - molecular size, charge, stoichiometry - their structural interaction with tubulin assemblies will be different from other tubulin-accessory protein copolymers studied in vitro.

Synthesis of acid-soluble spore proteins by Bacillus subtilis

1982 ◽  
Vol 152 (3) ◽  
pp. 1117-1125
Author(s):  
J M Leventhal ◽  
G H Chambliss
Keyword(s):  
Bacillus Subtilis ◽  
Maximum Rate ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Sodium Dodecyl ◽  
Molecular Weights ◽  
Spore Proteins ◽  
Major Acid

The major acid-soluble spore proteins (ASSPs) of Bacillus subtilis were detected by immunoprecipitation of radioactively labeled in vitro- and in vivo-synthesized proteins. ASSP synthesis in vivo began 2 h after the initiation of sporulation (t2) and reached its maximum rate at t7. This corresponded to the time of synthesis of mRNA that stimulated the maximum rate of ASSP synthesis in vitro. Under the set of conditions used in these experiments, protease synthesis began near t0, alkaline phosphatase synthesis began at about t2, and refractile spores were first observed between t7 and t8. In vivo- and in vitro-synthesized ASSPs comigrated in sodium dodecyl sulfate-polyacrylamide gels. Their molecular weights were 4,600 (alpha and beta) and 11,000 (gamma). The average half-life of the ASSP messages was 11 min when either rifampin (10 micrograms/ml) or actinomycin D (1 microgram/ml) was used to inhibit RNA synthesis.

Possible role of cyclic GMP in stimulus-secretion coupling by salt gland of the duck

1979 ◽  
Vol 237 (5) ◽  
pp. C200-C204 ◽  
Author(s):  
D. J. Stewart ◽  
J. Sax ◽  
R. Funk ◽  
A. K. Sen
Keyword(s):  
Cyclic Amp ◽  
Guanylate Cyclase ◽  
Cyclic Gmp ◽  
Salt Gland ◽  
Domestic Ducks ◽  
Stimulus Secretion Coupling ◽  
Stimulation Of

Stimulation of salt galnd secretion in domestic ducks in vivo increased the cyclic GMP concentration of the tissue, but had no effect on cyclic AMP levels. Methacholine, which is known to stimulate sodium transport by the glands both in vivo and in vitro, stimulated ouabain-sensitive respiration in salt gland slices. Cyclic GMP stimulated ouabain-sensitive respiration to the same extent as methacholine. Guanylate cyclase stimulators, hydroxylamine and sodium azide, also stimulated ouabain-sensitive respiration. The stimulation of ouabain-sensitive respiration by methacholine was blocked either by atropine or by removal of calcium from the incubation medium. The stimulation of ouabain-sensitive respiration by cyclic GMP still occurred in the absence of calcium. The above observations seem to indicate that cyclic GMP acts as a tertiary link in the process of stimulus-secretion coupling in the tissue.

scholarly journals Regulation of the synthesis of lutropin-induced protein in rat testis Leydig cells

1978 ◽  
Vol 170 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Felix H. A. Janszen ◽  
Brian A. Cooke ◽  
Maria J. A. Van Driel ◽  
Henk J. Van Der Molen
Keyword(s):  
Protein Synthesis ◽  
Cyclic Amp ◽  
Leydig Cells ◽  
Actinomycin D ◽  
Polyacrylamide Gel Electrophoresis ◽  
Phosphodiesterase Inhibitor ◽  
Dibutyryl Cyclic Amp ◽  
Rat Testis ◽  
Stimulation Of

The mechanism of action of lutropin on the stimulation of the synthesis of a specific lutropin-induced protein in rat testis Leydig cells was investigated. Lutropin-induced protein has a mol.wt. of approx. 21000 and is detected by labelling the Leydig-cell proteins with [35S]methionine, followed by separation by polyacrylamide-gel electrophoresis and radioautography of the dried gel. The incorporation of35S into lutropin-induced protein was used as an estimate for the synthesis of the protein. Incubation of Leydig cells with dibutyryl cyclic AMP or cholera toxin also resulted in the stimulation of synthesis of the protein. Synthesis of lutropin-induced protein, when maximally stimulated with 100ng of lutropin/ml, could not be stimulated further by addition of dibutyryl cyclic AMP. Addition of 3-isobutyl-1-methylxanthine, a phosphodiesterase inhibitor, further increased synthesis of the protein in the presence of a submaximal dose of lutropin (10ng/ml) but not in the absence of lutropin or with maximal amounts of lutropin (100 and 1000ng/ml). Actinomycin D prevented the effect of lutropin on the stimulation of lutropin-induced protein synthesis when added immediately or 1h after the start of the incubation, but not when added after 5–6h. This is interpreted as reflecting that, after induction of mRNA coding for lutropin-induced protein, lutropin had no influence on the synthesis of the protein in the presence of actinomycin D. Synthesis of the protein was also stimulated in vivo by injection of choriogonadotropin into rats 1 day after hypophysectomy, and the time course of this stimulation of lutropin-induced protein synthesis in vivo was similar to that obtained by incubating Leydig cells in vitro with lutropin. From these results it is concluded that stimulation of lutropin-induced protein synthesis by lutropin is most probably mediated by cyclic AMP and involves synthesis of mRNA.

Renal cyclic AMP accumulation and adenulate cyclase stimulation by erythropoietic agents

1975 ◽  
Vol 229 (5) ◽  
pp. 1387-1392 ◽  
Author(s):  
GM Rodgers ◽  
JW Fisher ◽  
WJ George
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Regional Distribution ◽  
Renal Medulla ◽  
Iron Incorporation ◽  
Erythropoietin Production ◽  
Cyclic Amp Accumulation ◽  
Stimulation Of

The regional distribution of cyclic AMP in the kidney was determined following erythropoietic stimulation with hypoxia and cobalt. Following these stimuli, increases in renal cyclic AMP concentrations were restricted to the cortex. The basis for this localization in the case of cobalt treatment was found to reside in the stimulation of renal cortical adenylate cyclase activity in vitro by concentrations of cobalt similar to those found in vivo. The level of cobalt in the cortex after cobalt treatment was found to approach 500 mumol/kg of tissue, whereas no detectable levels of cobalt were found in the renal medulla. Additionally, other agents such as parathyroid hormone and lactic acid, that are known to lack stimulatory effects on medullary adenylate cyclase, were found to stimulate the cortical enzyme. This stimulation of renal cortical adenylate cyclase correlates with enhanced erythropoiesis as demonstrated by increased radiolabeled iron incorporation into erythrocytes. These results support previous reports which suggest that renal cortical cyclic AMP mediates erythropoietin production in response to erythropoietically active agents.

Effects of hypoxia on testosterone release in rat Leydig cells

2009 ◽  
Vol 297 (5) ◽  
pp. E1039-E1045 ◽  
Author(s):  
Guey-Shyang Hwang ◽  
Szu-Tah Chen ◽  
Te-Jung Chen ◽  
Shyi-Wu Wang
Keyword(s):  
Calcium Channel ◽  
Adenylyl Cyclase ◽  
Intermittent Hypoxia ◽  
Leydig Cells ◽  
Channel Blocker ◽  
Male Rats ◽  
Plasma Testosterone ◽  
Testosterone Production

The aim of this study was to explore the effect and action mechanisms of intermittent hypoxia on the production of testosterone both in vivo and in vitro. Male rats were housed in a hypoxic chamber (12% O2 + 88% N2, 1.5 l/ml) 8 h/day for 4 days. Normoxic rats were used as control. In an in vivo experiment, hypoxic and normoxic rats were euthanized and the blood samples collected. In the in vitro experiment, the enzymatically dispersed rat Leydig cells were prepared and challenged with forskolin (an adenylyl cyclase activator, 10−4 M), 8-Br-cAMP (a membrane-permeable analog of cAMP, 10−4 M), hCG (0.05 IU), the precursors of the biosynthesis testosterone, including 25-OH-C (10−5 M), pregnenolone (10−7 M), progesterone (10−7 M), 17-OH-progesterone (10−7 M), and androstendione (10−7-10−5 M), nifedipine (L-type Ca2+ channel blocker, 10−6-10−4 M), nimodipine (L-type Ca2+ channel blocker, 10−5 M), tetrandrine (L-type Ca2+ channel blocker, 10−5 M), and NAADP (calcium-signaling messenger causing release of calcium from intracellular stores, 10−6-10−4 M). The concentrations of testosterone in plasma and medium were measured by radioimmunoassay. The level of plasma testosterone in hypoxic rats was higher than that in normoxic rats. Enhanced testosterone production was observed in rat Leydig cells treated with hCG, 8-Br-cAMP, or forskolin in both normoxic and hypoxic conditions. Intermittent hypoxia resulted in a further increase of testosterone production in response to the testosterone precursors. The activity of 17β-hydroxysteroid dehydrogenase was stimulated by the treatment of intermittent hypoxia in vitro. The intermittent hypoxia-induced higher production of testosterone was accompanied with the influx of calcium via L-type calcium channel and the increase of intracellular calcium via the mechanism of calcium mobilization. These results suggested that the intermittent hypoxia stimulated the secretion of testosterone at least in part via stimulatory actions on the activities of adenylyl cyclase, cAMP, L-type calcium channel, and steroidogenic enzymes.

scholarly journals Correlation of protein kinase activation and testosterone production after stimulation of Leydig cells with luteinizing hormone

1976 ◽  
Vol 160 (3) ◽  
pp. 439-446 ◽  
Author(s):  
B A Cooke ◽  
M L Lindh ◽  
F H A Janszen
Keyword(s):  
Protein Kinase ◽  
Luteinizing Hormone ◽  
Cyclic Amp ◽  
Protein Kinases ◽  
Leydig Cell ◽  
Leydig Cells ◽  
Kinase Activation ◽  
Testosterone Production ◽  
Protein Kinase Activation ◽  
Stimulation Of

The effect of different doses of luteinizing hormone on activation of protein kinases, cyclic AMP and testosterone production was studied in purified rat testis Leydig-cell preparations in the presence of 3-isobutyl-1-methylxanthine (a phosphodiesterase inhibitor). In addition, the nature of the protein kinases present in these cells and other tissues was investigated. The following results were obtained. 1. With all the amounts of luteinizing hormone used (0.1-1000 ng/ml), both activation of protein kinase and stimulation of testosterone production were demonstrated. With the lowest amount of luteinizing hormone (0.1 ng/ml), an 8.4±0.9% (S.E.M.,n=6) stimulation of protein kinase activation occurred, increasing to 100% with 1000 ng/ml, compared with 3.2±1.0%(S.E.M.,n=7) and 100% stimulation of testosterone production with 0.1 and 100 ng/ml respectively. 2. With amounts of luteinizing hormone up to 1 ng/ml (which gave half-maximal stimulation of testosterone production) no detectable increases in net cyclic AMP production were obtained. With higher amounts of luteinizing hormone, cyclic AMP production increased, but maximal production was not reached with 1000 ng/ml. 3. Two isoenzymic forms of protein kinase were present in Leydig cells and seminiferous tubules; type I was eluted with 0.075 M-and type II with 0.22-0.25 M-NaCl from DEAE-cellulose columns. 4. The protein kinase activity was not affected by the presence of erythrocytes in the Leydig-cell preparation, but varied depending on the type of histone used as substrate (histone F2b > mixed > histone F1).

In vivo and in vitro stimulatory effects of Cordyceps sinensis on testosterone production in mouse Leydig cells

Life Sciences ◽  
2003 ◽  
Vol 73 (16) ◽  
pp. 2127-2136 ◽  
Author(s):  
Chih-Chao Hsu ◽  
Yuan-Li Huang ◽  
Shaw-Jeng Tsai ◽  
Chia-Chin Sheu ◽  
Bu-Miin Huang
Keyword(s):  
Leydig Cells ◽  
Cordyceps Sinensis ◽  
Testosterone Production
Sign in / Sign up

Export Citation Format

Share Document