Hormonal control of tanning by the American cockroach: Cyclic AMP as a probable intermediate

1974 ◽  
Vol 20 (3) ◽  
pp. 623-627 ◽  
Author(s):  
Robert D. Vandenberg ◽  
Richard R. Mills
1993 ◽  
Vol 178 (1) ◽  
pp. 231-243 ◽  
Author(s):  
N. Audsley ◽  
G. M. Coast ◽  
D. A. Schooley

1. Manduca sexta diuretic hormone (Mas-DH) stimulates fluid secretion by adult Malpighian tubules of M. sexta, demonstrating its site of diuretic action in M. sexta for the first time. It was not possible to develop a suitable bioassay to measure fluid secretion in larval proximal tubules. 2. Mas-DH has an antidiuretic action on the cryptonephric complex of larval M. sexta because it increases fluid absorption from the rectum. It appears that in this complex Mas-DH is acting on a Na+/K+/2Cl- co-transporter, presumably on the basal membrane of the cryptonephric Malpighian tubules, because Mas-DH-stimulated fluid absorption by the cryptonephric complex is inhibited by bumetanide or the removal of Cl-, Na+ or K+ from the haemolymph side of the tissue. This is the first demonstration of hormonal control of fluid absorption by the cryptonephric complex. 3. Concomitant with the stimulation of fluid transport, Mas-DH increases the amount of cyclic AMP secreted by adult Malpighian tubules and the cryptonephric complex. In addition, Mas-DH promotes cyclic AMP production by the larval proximal tubules.


2000 ◽  
Vol 203 (2) ◽  
pp. 389-396 ◽  
Author(s):  
S. Morris ◽  
P. Greenaway ◽  
A.M. Adamczewska ◽  
M.D. Ahern

The terrestrial robber crab Birgus latro L. regulates the composition of its final excretory product (termed P) depending on the availability of dietary salt by reabsorbing ions from urine passed over the gills. Laboratory and field-based studies investigated the nature of the mechanisms of control of this branchial ion uptake. B. latro were prepared such that their branchial chambers could be perfused with artificial urine, and the rate of ion transport from the artificial urine was determined. For B. latro acclimated to drinking fresh water, the rates of Na(+) and Cl(−) uptake were more than four times those of crabs drinking 70 % sea water. Crabs were injected with either saline carrier or the same solution containing either dopamine or dibutyryl cyclic AMP (db-cAMP) (final concentration 8.7×10(−)(7)mol l(−)(1)haemolymph). Dopamine and db-cAMP inhibited Na(+) and Cl(−) uptake in animals acclimated to fresh water and markedly reduced their gill Na(+)/K(+)-ATPase activity. Dopamine stimulated the production of cyclic AMP within the branchial epithelial cells. Dopamine, released from the pericardial organs, acts as a primary messenger, and cyclic AMP acts as a second messenger most likely promoting phosphorylation of membrane proteins. In contrast to aquatic brachyuran crabs, ion transport in B. latro, an anomuran, is controlled via an inhibitory effect. Terrestrial crabs normally have access to fresh water and must salvage salt from their urine, and a mechanism to down-regulate a normally active uptake system seems more appropriate to their ecology. Whether the control is stimulatory or inhibitory in the various air-breathing crabs may depend on the osmoregulatory abilities of their aquatic ancestors, but in either case has significant implications for the evolution of crustaceans to life on land. Further work must establish whether terrestrial brachyuran crabs are similar to B. latro and whether this crab is unique amongst the anomuran crabs.


1985 ◽  
Vol 40 (9-10) ◽  
pp. 670-676 ◽  
Author(s):  
Gerd Gäde

Abstract Although crude extracts of cockroach (Periplaneta amencana) corpora cardiaca have been shown previously to affect the activity of adenylate cyclase and phosphorylase, we demonstrate in the present study for the first time that low concentrations (0.5 to 5 pmol) of the synthetic myoactive peptides. M I and M II, also affect these systems; these myoactive peptides are identical to the hypertrehalosaemic hormones I and II, and cause an increase in the concentration of the second messenger cyclic AMP in the fat body.In addition, both octapeptides activate fat body glycogen phosphorylase and promote breakdown of fat body glycogen. Both peptides increase the levels to haemolymph carbohydrate in a dose-dependent manner.


1983 ◽  
Vol 214 (3) ◽  
pp. 829-837 ◽  
Author(s):  
R Bartrons ◽  
L Hue ◽  
E Van Schaftingen ◽  
H G Hers

The ability of glucagon and of adrenaline to affect the concentration of fructose 2,6-bisphosphate in isolated hepatocytes was re-investigated because of important discrepancies existing in the literature. We were unable to detect a significant difference in the sensitivity of the hepatocytes with regard to the effect of glucagon to initiate the interconversion of phosphorylase, pyruvate kinase, 6-phosphofructo-2-kinase and fructose 2,6-bisphosphatase, and also to cause the disappearance of fructose 2,6-bisphosphate. In contrast, we have observed differences in the time-course of these various changes, since the interconversions of phosphorylase and of pyruvate kinase were at least twice as fast as those of 6-phosphofructo-2-kinase and of fructose 2,6-bisphosphatase. When measured in a cell-free system in the presence of MgATP, the cyclic AMP-dependent interconversion of pyruvate kinase was 5-10-fold more rapid than those of 6-phosphofructo-2-kinase and of fructose 2,6-bisphosphatase. These data indicate that 6-phosphofructo-2-kinase and fructose 2,6-bisphosphatase are relatively poor substrates for cyclic AMP-dependent protein kinase; they also support the hypothesis that the two catalytic activities belong to a single protein. Adrenaline had only a slight effect on the several parameters under investigation, except for the activation of phosphorylase. In the absence of Ca2+ ions from the incubation medium, however, adrenaline had an effect similar to that of glucagon.


1991 ◽  
Vol 274 (2) ◽  
pp. 433-438 ◽  
Author(s):  
R A Mooney ◽  
K L Bordwell

1. In the adipocyte, phosphorylation/dephosphorylation of regulatory proteins is a common mechanism of metabolic regulation. We have observed a very prominent phosphoprotein doublet of 61 kDa and 63 kDa in rat adipocytes that is markedly responsive to hormones. The 63 kDa band was the predominant phosphoprotein in the cell in response to 0.1 microM-isoprenaline, whereas the 61 kDa band was nearly absent. Insulin alone did not alter 32P incorporation into the doublet, but partially counteracted the effects of isoprenaline, decreasing label in the 63 kDa band by as much as 50% and resulting in the reappearance of the 61 kDa band. 2. Subcellular fractionation demonstrated that both phosphoprotein bands were fat-associated. Neither insulin nor isoprenaline altered this localization. Peptide maps (one-dimensional) of the 61/63 kDa bands demonstrated close sequence similarity. Amino acid analysis revealed the presence of phosphoserine and phosphothreonine. The latter was more prominent in the 61 kDa band. Isoprenaline caused an absolute increase in both phosphoamino acids. 3. Permeabilization of 32P-labelled isoprenaline-treated cells with digitonin initiated rapid dephosphorylation of the 63 kDa band, with reappearance of the 61 kDa band. Insulin increased the rate of dephosphorylation by 2-3-fold when present with isoprenaline before permeabilization. 4. In permeabilized adipocytes, cyclic AMP (1 microM-1 mM) increased phosphorylation of the 61/63 kDa doublet by 4-10-fold in the presence of [gamma-32P]ATP, but insulin had no effect. 5. We conclude that this prominent phosphoprotein, migrating as a 61/63 kDa doublet, is coupled to the cyclic AMP-dependent protein kinase and is associated with an insulin-stimulated phosphoprotein phosphatase activity. This fat-associated phosphoprotein, which is under counter-regulatory hormonal control, may play a role in hormone-dependent lipid metabolism.


1974 ◽  
Vol 139 (6) ◽  
pp. 1395-1414 ◽  
Author(s):  
L. J. Ignarro ◽  
T. F. Lint ◽  
W. J. George

The purpose of this investigation was to examine the effects of autonomic neurohormones, cyclic nucleotides, and related agents on the immunologic discharge of lysosomal enzymes from, and phagocytosis by, purified human neutrophils. In order to discern the possible intracellular mechanisms by which certain neurohormones influence neutrophil function, the concentrations of cyclic AMP and cyclic GMP in neutrophils were assessed during cell contact with phagocytizable particles and autonomic agents. The model system employed for study was the interaction of purified human neutrophils with rheumatoid arthritic (RA) serum-treated zymosan particles at 37°C in a neutral, balanced salt solution containing glucose. Neutrophils ingested the particles and discharged ß-glucuronidase but not lactate dehydrogenase activity during 30 min of incubation. Treatment of zymosan particles with RA serum was more effective than treatment with normal serum with regard to the extent of both particle uptake and lysosomal enzyme release. During contact of neutrophils with RA serum-treated zymosan particles epinephrine, isoproterenol, and cyclic AMP inhibited both particle ingestion and ß-glucuronidase discharge. These actions of epinephrine were associated with a concomitant elevation of cyclic AMP levels. In contrast to the actions of catecholamines and cyclic AMP, acetylcholine and cyclic GMP accelerated lysosomal enzyme release without affecting particle uptake. The actions of acetylcholine were associated with a concomitant elevation of cyclic GMP levels. Increases in neutrophil levels of cyclic GMP but not of cyclic AMP were associated also with the discharge of ß-glucuronidase provoked by particles in the absence of added cholinergic agents. The data suggest that the immunologic release of lysosomal enzymes from human neutrophils can be regulated by autonomic neurohormones, perhaps via the selective formation of appropriate nucleotides.


1987 ◽  
Vol 65 (6) ◽  
pp. 1509-1514 ◽  
Author(s):  
J. W. D. Gole ◽  
G. L. Orr ◽  
R. G. H. Downer

The injection of 10 μL of 5 × 10−3 M octopamine into the haemocoel of adult male Periplaneta americana results in a 20 × increase in haemolymph cyclic AMP (cAMP) levels within 3 min. Synephrine also causes a marked increase in haemolymph cAMP, and less pronounced elevations were obtained following the injection of tyramine, dopamine, norepinephrine, 5-hydroxytryptamine, phenylethanolamine, β-phenylethylamine, and L-phenylephrine. The octopamine effect is time dependent for at least 10 min and dose dependent with the EC50 for the injected dose calculated to be about 2.5 × 10−3 M. These results indicate that the octopamine response is receptor mediated and studies on isolated haemocytes suggest that the octopamine-sensitive receptors are located on haemocytes. Incubation of whole haemocytes in medium containing octopamine results in a dose-dependent elevation of cAMP with the EC50 calculated at about 7.5 × 10−6 M. Synephrine, tyramine, and dopamine also elevate cAMP levels in incubated haemocytes, and the activator of adenylate cyclase, forskolin, causes a marked increase in cAMP. The octopamine-mediated response is blocked by mianserin, phentolamine, and cyproheptadine but not by the β-adrenergic blocking agents propranolol and dichloroisoproterenol.


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