Antidiuretic action of cyclic AMP, corpus cardiacum, and ventral ganglia on fluid absorption across locust ileum in vitro

1989 ◽  
Vol 67 (11) ◽  
pp. 2655-2661 ◽  
Author(s):  
R. A. Lechleitner ◽  
N. Audsley ◽  
J. E. Phillips
Keyword(s):  
Cyclic Amp ◽  
Fluid Transport ◽  
Physiological Saline ◽  
Dependent Manner ◽  
Fluid Absorption ◽  
Corpus Cardiacum ◽  
Ventral Ganglion ◽  
Osmotic Concentration ◽  
Osmotic Permeability

Locust ileal fluid transport (3.0–3.5 μL/h per ileum) and tissue volume were nearly constant after the 1st hour of incubation in physiological saline. Inhibition of absorption by KCN + iodoacetic acid and by azide indicated metabolic dependence of fluid transport. Fluid absorption occurred against osmotic concentration differences of up to 600 mosmol (luminal osmolarity > hemocoel osmolarity). Fluid absorption was stimulated by cyclic AMP, by both nervous and glandular lobes of the corpus cardiacum, and by the fifth ventral ganglion in a dose-dependent manner. All stimulants caused ilea to absorb against larger osmotic concentration differences. Stimulants in corpus cardiacum and fifth ventral ganglion extracts increased the osmotic permeability of the ileal wall at low osmotic concentration differences, whereas cyclic AMP had a much smaller effect on osmotic permeability. The absorbate remained hyperosmotic to the luminal saline under all conditions, and stimulants increased absorbate osmolarity.

Corpus cardiacum stimulated trehalose efflux from cockroach (Periplaneta americana) fat body: control by calcium

1985 ◽  
Vol 63 (1) ◽  
pp. 63-66 ◽  
Author(s):  
J. E. Steele ◽  
T. Paul
Keyword(s):  
Cyclic Amp ◽  
Periplaneta Americana ◽  
Saline Solution ◽  
Fat Body ◽  
Surrounding Medium ◽  
Physiological Saline ◽  
Corpus Cardiacum ◽  
Physiological Saline Solution ◽  
Stimulation Of

Cockroach fat body incubated in a simple physiological saline solution releases trehalose to the surrounding medium. The output of trehalose occurs in the absence of ambient Ca2+ and decreases slowly with time. In two separate experiments, 0.1 mM CaCl2 added to the saline increased the output of trehalose on average by 70% but higher concentrations of Ca2+ did not further increase the efflux of trehalose. Stimulation of trehalose efflux by corpus cardiacum extract is absolutely dependent on extracellular Ca2+, no increase occurring beyond the basal level in the absence of the ion. The activity of corpus cardiacum extract increases as the concentration of CaCl2 is increased to 0.5 mM. This concentration of Ca2+ in the saline permits the extract to increase trehalose efflux by as much as 60% above the basal level. Corpus cardiacum extract, as well as the hypertrehalocaemic agents cyclic AMP and theophylline, increase significantly the influx of Ca2+ into fat body in vitro. The basal efflux of trehalose from fat body and that stimulated by corpus cardiacum extract is not dependent on extracellular Mg2+.

Composition of fluid transported by locust ileum: influence of natural stimulants and luminal ion ratios

1989 ◽  
Vol 67 (11) ◽  
pp. 2662-2668 ◽  
Author(s):  
R. A. Lechleitner ◽  
N. Audsley ◽  
J. E. Phillips
Keyword(s):  
Fluid Transport ◽  
Direct Evidence ◽  
High Capacity ◽  
Fold Increase ◽  
Hormonal Control ◽  
Corpus Cardiacum ◽  
Ventral Ganglion ◽  
Nacl Transport ◽  
Stimulation Of

Unstimulated fluid transport by everted locust ileal sacs in vitro was supported at 50% of control levels by the presence externally of any one of Na+, K+, or Cl−, whereas removal of all but trace levels of these ions reduced fluid transport to 25% of control transport rates. Stimulation of fluid transport by corpus cardiacum or fifth ventral ganglion extracts did not occur unless Cl− was present. The presence of Na+ or K+ was also required for maximum stimulation of fluid transport by these factors, the greatest stimulation occurring when the Na+:K+ ratio was 1:1. Cyclic AMP, and corpus cardiacum and fifth ventral ganglion extracts all stimulated Na+, Cl−, and K+ absorption across everted ileal sacs. Stimulation of fluid transport by these factors largely eliminated the anion deficit (Na+ + K+−Cl−) observed under unstimulated conditions. Stimulation caused large decreases in absorbate [Formula: see text] concentrations and pH concurrent with the increased absorbate Cl− levels. These results indicate a switch from low-capacity NaHCO3 plus NaCl transport under unstimulated conditions to high-capacity NaCl transport under stimulated conditions. Stimulation of fluid transport also causes a 3-fold increase in transepithelial potential (hemocoel negative), indicating stimulation of electrogenic anion (Cl−) movement to the hemocoel. These results provide the first direct evidence for hormonal control of Na+ reabsorption in insect excretory systems.

scholarly journals Antidiuretic Action of a Corpus Cardiacum Factor (CTSH) on Long-Term Fluid Absorption Across Locust Recta in Vitro

1984 ◽  
Vol 113 (1) ◽  
pp. 409-421 ◽  
Author(s):  
B. PROUX ◽  
J. PROUX ◽  
J. E. PHILLIPS
Keyword(s):  
Active Transport ◽  
Chloride Transport ◽  
Rectal Wall ◽  
Fluid Absorption ◽  
Corpus Cardiacum ◽  
Osmotic Permeability ◽  
Antidiuretic Action ◽  
Stimulation Of

Long-term fluid absorption (Jv) by everted rectal sacs from locusts is stimulated by both corpus cardiacum (CC) extracts and cAMP in a dosedependent manner. This hormonal antidiuretic activity (ADH) is present in both nervous and glandular lobes of CC. This distribution is similar to that of chloride transport stimulating hormone (CTSH) but not to that of other factors previously reported from this gland. As expected if ADH were due to CTSH acting on electrogenic Cl− transport, CC extracts also increased the electropotential across rectal sacs, and the stimulation of fluid absorption ceased in Cl-free salines. CC extracts also caused recta to absorb fluid against larger osmotic gradients, suggesting that the antidiuretic factor acts on the ion-dependent active transport of fluid rather than on the osmotic permeability of the rectal wall.

THE EFFECTS OF MANDUCA SEXTA DIURETIC HORMONE ON FLUID TRANSPORT BY THE MALPIGHIAN TUBULES AND CRYPTONEPHRIC COMPLEX OF MANDUCA SEXTA

1993 ◽  
Vol 178 (1) ◽  
pp. 231-243 ◽  
Author(s):  
N. Audsley ◽  
G. M. Coast ◽  
D. A. Schooley
Keyword(s):  
Cyclic Amp ◽  
Manduca Sexta ◽  
Fluid Transport ◽  
Basal Membrane ◽  
Fluid Secretion ◽  
Hormonal Control ◽  
Malpighian Tubules ◽  
Proximal Tubules ◽  
Fluid Absorption ◽  
Diuretic Hormone

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.

Biochemical parameters regulating forward motility initiation in vitro in goat immature epididymal spermatozoa

1998 ◽  
Vol 10 (4) ◽  
pp. 299 ◽  
Author(s):  
Bijay S. Jaiswal ◽  
Gopal C. Majumder
Keyword(s):  
Cyclic Amp ◽  
Sperm Motility ◽  
Biochemical Parameters ◽  
Vital Role ◽  
Dependent Manner ◽  
Alkaline Ph ◽  
Heat Stable ◽  
Heat Stable Protein ◽  
Dose Dependent

An investigation was carried out to analyse the biochemical parameters influencing forward motility (FM) initiation in vitro in the goat caput-epididymal immature spermatozoa. Forward motility was induced in approximately 55% of caput-sperm upon incubation in an alkaline (pH 8.0) modified Ringer’s solution containing theophylline (30 mM) (an inhibitor of cyclic AMP phosphodiesterase), dialysed epi-didymal plasma (EP) and bicarbonate. Both EP and bicarbonate induced sperm motility in a dose-dependent manner, and at saturating doses EP (0.6 mg protein mL–1) and bicarbonate (25 mM) induced FM in approx-imately 38% and 44% of the cells, respectively. The motility-promoting efficacy of EP was attributed to a heat-stable protein termed ‘forward motility protein’ (FMP). Bicarbonate served as an initiator as well as a stabilizer of FM and its action was not dependent on FMP. FMP can induce FM in the caput-sperm, but it is not essential for sperm motility initiation. Alteration of the medium pH from 6.60 to 8.00 caused a marked increase in the EP or bicarbonate-dependent sperm FM initiation, as well as intrasperm pH. At the physio-logical pH, bicarbonate served as a much more potent motility activator than FMP, although both the motility promoters showed maximal efficacy at alkaline pH (~7.8). EP as well as bicarbonate elevated the intrasperm cyclic AMP level. Unlike EP, bicarbonate is capable of increasing intrasperm pH. The intrasperm pH increased from 6.54 0.02 to 6.77 0.03 during sperm transit from caput to cauda. The data are con-sistent with the view that FMP activates sperm forward motility by enhancing the intrasperm cyclic AMP level and that extracellular bicarbonate and pH play a vital role in the initiation of sperm FM during the epi-didymal transit.

scholarly journals Rainbow trout hypocalcin stimulates bone resorption in embryonic mouse calvaria in vitro in a PTH-like fashion

1989 ◽  
Vol 143 (1) ◽  
pp. 165-175
Author(s):  
F. P. Lafeber ◽  
M. P. Herrmann-Erlee ◽  
G. Flik ◽  
S. E. Wendelaar Bonga
Keyword(s):  
Bone Resorption ◽  
Cyclic Amp ◽  
Tertiary Structure ◽  
Lactate Production ◽  
Dependent Manner ◽  
Embryonic Mouse ◽  
Molar Basis ◽  
Mouse Calvaria ◽  
Dose Dependent

Hypocalcin, the major hormone with hypocalcaemic action in fish, was isolated from trout corpuscles of Stannius (SCs). The bioactivity of hypocalcin was assessed in a parathyroid hormone (PTH) bioassay involving bone resorption in embryonic mouse calvaria. Calcium and phosphate release and lactate production were stimulated in a dose-dependent manner by hypocalcin. On a molar basis about equal amounts of hypocalcin and PTH were required to obtain similar effects in this assay. Hypocalcin did not stimulate cyclic AMP production either in mouse calvaria or in cultured osteoblasts. In this respect hypocalcin resembles shortened or N-terminus-modified PTH molecules that induce bone resorption without increasing cyclic AMP levels. Since hypocalcin and PTH have comparable bioactivity in this mammalian bioassay (as well as in fish bioassays), we tentatively suggest that both hormones are structurally similar and that both hormones may act via the same receptors. The two hormones show no resemblance to one another in primary structure, so we suggest that they have similarities in tertiary structure.

The Relation of Blood Adenosine Triphosphate to Changes of Mood in Affective Disorders

1974 ◽  
Vol 125 (586) ◽  
pp. 268-274 ◽  
Author(s):  
Otto Hansen ◽  
Maria Dimitrakoudi
Keyword(s):  
Cyclic Amp ◽  
Adenosine Triphosphate ◽  
Whole Blood ◽  
Dependent Manner ◽  
Uridine Diphosphate ◽  
Healthy Human ◽  
Electroconvulsive Treatment ◽  
Concentration Dependent Manner ◽  
Depressive Patients

Peripheral whole blood uridine diphosphate glucose (UDPG) has been found to be significantly elevated in psychotic depression (Hansen, 1969; 1972a, b), and this was related to an equally significant lowering of whole blood adenosine triphosphate (ATP). Addition to healthy human blood of UDPG accelerated the hydrolysis of ATP in vitro (Hansen, 1972a), and UDPG concentration dependently enhanced the activity of a vegetable ATP di-phosphohydrolase (EC 3.6.1.5), which was also inhibited by adenosine 3’, 5′-cyclic monophosphate (cyclic AMP) in a concentration-dependent manner (Hansen, 1972b). Other workers have recently published a similar inhibition of a rat heart ATPase by cyclic AMP (Dietze and Hepp, 1972), and another research group have found that sodium-potassium exchange pump changes and changes in erythrocyte membrane ATPase activity correlate significantly with mood alterations in psychotic depressive patients (Dick, Dick, Le Poidevin and Naylor, 1972; Naylor, Dick, Dick, Le Poidevin and Whyte, 1973). This paper reports a study of the relationship between blood ATP levels and mood in patients suffering from manic-depressive predictable (Jenner, 1971) short term cycle psychotic states, and in depressive patients receiving electroconvulsive treatment.

Serotonin enhances oestradiol production by hamster preovulatory follicles in vitro: effects of experimentally induced atresia

1990 ◽  
Vol 125 (3) ◽  
pp. 433-438 ◽  
Author(s):  
P. F. Terranova ◽  
J. Th. J. Uilenbroek ◽  
L. Saville ◽  
D. Horst ◽  
Y. Nakamura
Keyword(s):  
Cyclic Amp ◽  
Dependent Manner ◽  
Glucose Medium ◽  
Preovulatory Follicles ◽  
In Vitro Effects ◽  
Dose Dependent ◽  
Oestradiol Production

ABSTRACT Preovulatory follicles from adult hamsters on the morning of pro-oestrus were used in this study. Serotonin stimulated oestradiol production by preovulatory follicles during a 5-h incubation in 1 ml Krebs–Ringer bicarbonate glucose medium containing isobutylmethylxanthine (0.1 mmol/l; IBMX) and androstenedione (1 μmol/l). The enhanced oestradiol production by serotonin was dependent on the dose of IBMX and androstenedione. Mianserin, a serotonin type-1 and serotonin type-2 receptor antagonists, prevented the serotonin-enhanced oestradiol production in a dose-dependent manner. Ketanserin, a specific serotonin type-2 receptor antagonist, was ineffective in blocking the action of serotonin, indicating that the effect of serotonin was mediated by the serotonin type-1 receptor. In the presence of androstenedione (1 μmol/l), serotonin was unable to enhance oestradiol production in isolated granulosa cells. It was also unable to enhance oestradiol production in early atretic follicles; atresia was induced experimentally by an injection of phenobarbital in order to prevent ovulation. The data indicate that serotonin stimulates oestradiol production by hamster preovulatory follicles in vitro. The mechanism of action of serotonin involves an intact healthy follicle, a serotonin type-1 receptor and possibly cyclic AMP. The increased oestradiol secretion might be related to increased androgen production by the follicle and increased permeability (leakiness) of the follicle to androstenedione which serves as substrate for aromatization to oestradiol by the granulosa cell. Journal of Endocrinology (1990) 125, 433–438

Biological activity of a growth hormone-releasing factor secreted by a human tumor

1983 ◽  
Vol 244 (4) ◽  
pp. E346-E353
Author(s):  
M. J. Cronin ◽  
A. D. Rogol ◽  
R. M. MacLeod ◽  
D. A. Keefer ◽  
I. S. Login ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Cyclic Amp ◽  
Islet Cell Tumor ◽  
Hormone Secretion ◽  
Human Tumor ◽  
Pituitary Cells ◽  
Dependent Manner ◽  
Luteinizing Hormone Secretion ◽  
Pancreatic Islet Cell

A substance released by a pancreatic islet cell tumor induced signs and symptoms of acromegaly in a young woman. The culture medium in which the tumor was placed after resection was added to rat anterior pituitary cells and incubated in vitro. Both newly synthesized and total rat growth hormone (GH) release as well as cellular cyclic AMP accumulation were stimulated in a dose-dependent manner by the tumor medium. Coincubation with somatostatin blocked these effects. The increase of cyclic AMP preceded the enhanced GH release, indicating that cyclic AMP may be a second messenger for the tumor factor(s). Neither prolactin nor luteinizing hormone secretion was affected by the tumor medium. When measured by a perfused cell column apparatus, there was a rapid and dramatic release of GH by the dispersed rat pituitary cells during a 2.5-, 10-, and 40-min pulse of tumor medium; both the onset and termination of the GH response reached maximal or control values, respectively, within 5 min. Pretreatment of the tumor medium with pepsin markedly attenuated the tumor medium activity, indicating the peptide nature of the factor(s). Finally, ultrastructural analysis indicated that the somatotrophs were degranulated by the tumor medium, whereas there was no similar effect apparent on the mammotrophs. Whether this tumor polypeptide is identical to native hypothalamic GH-releasing hormone remains to be proved.

scholarly journals Cyclic AMP-Dependent Kinase Regulates Raf-1 Kinase Mainly by Phosphorylation of Serine 259

2002 ◽  
Vol 22 (10) ◽  
pp. 3237-3246 ◽  
Author(s):  
Amardeep S. Dhillon ◽  
Claire Pollock ◽  
Helge Steen ◽  
Peter E. Shaw ◽  
Harald Mischak ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Kinase Activity ◽  
Dependent Manner ◽  
Dependent Protein Kinase ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Dependent Protein ◽  
Kinase Pathway

ABSTRACT The Raf-1 kinase activates the ERK (extracellular-signal-regulated kinase) pathway. The cyclic AMP (cAMP)-dependent protein kinase (PKA) can inhibit Raf-1 by direct phosphorylation. We have mapped all cAMP-induced phosphorylation sites in Raf-1, showing that serines 43, 259, and 621 are phosphorylated by PKA in vitro and induced by cAMP in vivo. Serine 43 phosphorylation decreased the binding to Ras in serum-starved but not in mitogen-stimulated cells. However, the kinase activity of a RafS43A mutant was fully inhibited by PKA. Mutation of serine 259 increased the basal Raf-1 activity and rendered it largely resistant to inhibition by PKA. cAMP increased Raf-1 serine 259 phosphorylation in a PKA-dependent manner with kinetics that correlated with ERK deactivation. PKA also decreased Raf-1 serine 338 phosphorylation of Raf-1, previously shown to be required for Raf-1 activation. Serine 338 phosphorylation of a RafS259A mutant was unaffected by PKA. Using RafS259 mutants we also demonstrate that Raf-1 is the sole target for PKA inhibition of ERK and ERK-induced gene expression, and that Raf-1 inhibition is mediated mainly through serine 259 phosphorylation.

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