Reaction in vitro of synthetic oxytocin and lysine-vasopressin with the pseudoisocyaninchloride technique used for the demonstration of neurohypophysial neurosecretory material

1969 ◽  
Vol 17 (1) ◽  
pp. 73-77 ◽  
Author(s):  
M. Gutierrez ◽  
J. C. Sloper
Keyword(s):  
Neurosecretory Material ◽  
Lysine Vasopressin ◽  
Synthetic Oxytocin

THE UPTAKE OF TRITIATED LYSINE VASOPRESSIN BY RAT AND PIG PITUITARY NEURAL LOBES IN VITRO

1971 ◽  
Vol 50 (4) ◽  
pp. 669-677 ◽  
Author(s):  
B. A. EDWARDS
Keyword(s):  
Tap Water ◽  
Exchange Chromatography ◽  
Control Group ◽  
Breakdown Product ◽  
Nacl Solution ◽  
Water Control ◽  
Neural Lobe ◽  
Lysine Vasopressin ◽  
And Control

SUMMARY Uptake of tritiated lysine vasopressin ([3H]LVP) was studied in halved neural lobes of rats (which had been given either tap water (control group) or 2% (w/v) NaCl solution as drinking water for 4 days) as well as in slices of pig neural lobe. Uptake of radioactivity into the neural lobes was shown but analysis of the extracts of incubated lobes of both species by ion exchange chromatography showed that very little of it remained in the tissue as hormone. In addition, some radioactivity was associated with trichloroacetic acid-insoluble proteins. After 90 min of incubation, and after correction for the breakdown, the uptake of unchanged [3H]LVP, expressed as a tissue: medium ratio, was 0·14 ± 0·04 and 0·09 ± 0·03 (mean ± s.e.m.) for the saline-treated and control rats respectively, while the tissue: medium ratios for the breakdown product(s) were 6·47 ± 0·45 and 5·50 ± 0·36. The results suggest uptake of [3H]LVP into the cell with almost complete intracellular breakdown of the hormone.

Responses of nerve-free vessels to vasoactive amines and polypeptides

1965 ◽  
Vol 208 (4) ◽  
pp. 748-753 ◽  
Author(s):  
Avril V. Somlyo ◽  
Chi-Yuan Woo ◽  
Andrew P. Somlyo
Keyword(s):  
Umbilical Artery ◽  
Main Pulmonary Artery ◽  
Umbilical Vessels ◽  
Vasoconstrictor Response ◽  
Human Umbilical Artery ◽  
Vasoconstrictor Effect ◽  
Rhythmic Contractions ◽  
Synthetic Oxytocin ◽  
Indirect Action

Contractile responses of helically cut strips of noninnervated human umbilical artery and vein were determined. Spontaneous, rhythmic contractions were exhibited by both preparations, but were greater in magnitude and duration in umbilical veins. Vasoconstriction elicited by sympathomimetic amines was variable, and generally of a low order. The response to norepinephrine was not potentiated by cocaine (10 µg/ml) but was blocked by Dibenamine (1.0–1.5 µg/ml). Umbilical vasoconstrictor response to tyramine (1.0–10.0 µg/ml) indicated the direct vasoconstrictor effect of this agent. The similar norepinephrine-to-tyramine sensitivity ratios of umbilical vessels and canine main pulmonary artery were interpreted as evidence against the indirect action of tyramine in vitro. Isoproterenol produced no vasodilation in umbilical vessels, suggesting the absence of ß-adrenergic pathways. Oxytocin (>>0.1 mU/ml) was a highly effective umbilical vasoconstrictor. Native and synthetic oxytocin preparations were equiactive and produced tachyphylaxis to each other. Native and synthetic lysine-8-vasopressin (>>0.005 U/ml) and angiotensin amide (>>0.002 µg/ml) produced only minimal and inconsistent vasoconstriction, while serotonin (>>0.004 µg/ml) was as effective as oxytocin.

The effect of arginine vasotocin on the isolated amniotic membrane of the guinea pig

1974 ◽  
Vol 52 (3) ◽  
pp. 371-386 ◽  
Author(s):  
E. Vizsolyi ◽  
A. M. Perks
Keyword(s):  
Average Rate ◽  
Individual Variability ◽  
Arginine Vasotocin ◽  
Maternal Environment ◽  
Amniotic Cavity ◽  
Net Uptake ◽  
Fetal Urine ◽  
Amniotic Membranes ◽  
Synthetic Oxytocin

Amniotic membranes from fetal guinea pigs at 0.46 of term were maintained in vitro by means of salines which reproduced the electrolytes of the natural fluids, and. which maintained small osmotic and hydrostatic gradients from the fetal to the maternal solutions. Water passed slowly from the fetal to the maternal side (average rate = 3.93 mg/cm2 per minute). Synthetic arginine vasotocin (AVT) at 8–100 vasopressor mU/ml of amniotic saline slowed the fetal–maternal flow, or reversed it to give a net uptake of water into the amniotic saline (maximum reversed flow = 10.4 mg/cm2 per minute). Despite individual variability between membranes, there was a linear relationship between the change in the rate of flow, and the log of the dose of AVT (AVT threshold indicated = 6.4 mU/ml). Synthetic arginine vasopressin (AVP) and fetal pituitary extracts produced similar responses (AVP threshold = about 1.0 mU/ml). Synthetic oxytocin was without effect in doses up to 100 oxytocic mU/ml. Although the doses tested appeared to be pharmacological, evidence is reviewed for a possible physiological significance. It is suggested that amounts of AVT, or more probably AVP, are liberated from the fetal pituitary by osmotic or other stimuli, and pass in the fetal urine into the amniotic cavity; there they act on the amnion to stimulate it to conserve or augment amniotic fluid by transporting water inwards from the maternal environment.

RELEASE OF THYROTROPHIN IN VIVO AND IN VITRO BY SYNTHETIC NEUROHYPOPHYSIAL HORMONES

1964 ◽  
Vol 42 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Frank S. LaBella
Keyword(s):  
Dose Response ◽  
In Vitro Release ◽  
Optimal Level ◽  
Response Curves ◽  
Low Concentrations ◽  
Pituitary Glands ◽  
In Vivo Effects ◽  
Synthetic Oxytocin

The influence of synthetic oxytocin and synthetic lysine-8-vasopressin on the release of thyrotrophin (TSH) from slices of the "basophilic" zone of bovine anterior pituitary glands was determined. Up to 10-fold stimulation of TSH release occurred in the presence of the peptide hormones at low concentrations (approximately 10−11 to 10−9 M). Concentrations greater than 10−9 M were less stimulatory, ineffective, or inhibitory. In general, vasopressin stimulated at lower concentrations than did oxytocin. The dose–response curve of oxytocin began to descend at lower concentrations than did that of vasopressin.Stimulation of I131 discharge from the thyroids of propylthiouracil (PTU)-treated, day-old chicks was produced by the intraperitoneal injection of as little as 4 ng vasopressin or 25 ng oxytocin. As the injected dose of either peptide was increased beyond an optimal level, there was less enhancement of I131 discharge, and, with further increases, inhibition. The decreasing response began with lower doses of oxytocin than of vasopressin. The similarities of the dose–response curves of thyroid I131 discharge and of in vitro release of TSH indicate that the in vivo effects of injected neurohypophysial peptides are mediated through the release of endogenous TSH.

In vitro inhibition of pituitary prolactin synthesis and release by hypothalamic extract

1963 ◽  
Vol 205 (2) ◽  
pp. 213-218 ◽  
Author(s):  
P. K. Talwalker ◽  
A. Ratner ◽  
J. Meites
Keyword(s):  
Cerebral Cortex ◽  
Anterior Pituitary ◽  
Acid Extract ◽  
Prolactin Release ◽  
Lysine Vasopressin ◽  
In Vitro Inhibition ◽  
Hormone Inactivation ◽  
Prolactin Synthesis ◽  
Pituitary Prolactin

When rat anterior pituitary (AP) was incubated at 37.5 C in a Dubnoff metabolic shaker for 2 hr, 169% more prolactin was found in the combined medium and AP than in nonincubated AP. When AP was incubated together with homogenate or acid extract of rat hypothalamus, prolactin levels in the medium and AP were markedly decreased (36–75%), indicating inhibition of synthesis and release. Acid extract of rat cerebral cortex had no effect on prolactin synthesis or release. Incubation of ovine or rat prolactin, with or without hypothalamus, did not decrease prolactin activity, demonstrating that hypothalamic inhibition of AP prolactin production was not due to hormone inactivation. Acetylcholine, epinephrine, norepinephrine, serotonin, histamine, substance P, oxytocin, and arginine or lysine vasopressin had no effect on AP prolactin release. These results indicate that the hypothalamus contains a factor(s) which inhibits synthesis and release of prolactin by the rat AP in vitro, and this factor(s) is not any of the recognized neurohumors in the hypothalamus.

NEUROHYPOPHYSIAL HORMONES AND RELEASE OF GONADOTROPHINS

1959 ◽  
Vol 18 (3) ◽  
pp. 245-250 ◽  
Author(s):  
L. MARTINI ◽  
L. MIRA ◽  
A. PECILE ◽  
S. SAITO
Keyword(s):  
Intravenous Injection ◽  
Significant Rise ◽  
Normal Female ◽  
Posterior Pituitary ◽  
Mouse Uterus ◽  
Physiological Regulation ◽  
Neurohypophysial Hormones ◽  
Lysine Vasopressin ◽  
Before And After ◽  
Synthetic Oxytocin

SUMMARY The gonadotrophin-releasing activity of hypothalamo-neurohypophysial hormones has been investigated in normal female rabbits. Pooled urine, obtained before and after intravenous injection of different posterior pituitary preparations (Pitressin, Pitocin, lysine-vasopressin and synthetic oxytocin), was extracted by the kaolin-acetone method and assayed by the mouse uterus test. All the posterior pituitary preparations used induced a significant rise in the release of gonadotrophins. The experiments suggest that posterior pituitary polypeptides may play a role in the physiological regulation of gonadotrophin release.

Activation of vasopressin hormonogens by kidney aminoacylarylamidase; Study in vitro

1980 ◽  
Vol 45 (3) ◽  
pp. 772-776
Author(s):  
Karel Hauzer ◽  
Tomislav Barth ◽  
Karel Jošt
Keyword(s):  
Time Course ◽  
Biological Method ◽  
Mammalian Kidney ◽  
Lysine Vasopressin ◽  
The Individual

Under conditions in vitro the mammalian kidney aminoacylarylamidase splits off the individual glycine residues from the hormonogens of vasopressin and its analogs of the triglycyl-vasopressin type (triglycyl[8-lysine]vasopressin, triglycyl[8-ornithine]vasopressin and des-glycineamide triglycyl[8-lysine]vasopressin) generating consequently the hormone or its analogues. The time course of the reaction was followed by the biological method (pressoric assy) and by determing the concentration of the liberated glycine. The generated hormone or its analogues are resistant to the action of the enzyme used.

STUDIES ON THE ENZYMATIC DEGRADATION OF OXYTOCIN AND VASOPRESSIN BY HUMAN PREGNANCY SERA

1967 ◽  
Vol 54 (4) ◽  
pp. 618-628 ◽  
Author(s):  
A. M. Riad
Keyword(s):  
Paper Chromatography ◽  
Enzymatic Degradation ◽  
Peptide Bond ◽  
Cysteic Acid ◽  
Tyrosine Residue ◽  
Enzymatic Cleavage ◽  
Amino Terminal ◽  
Lysine Vasopressin ◽  
Synthetic Oxytocin ◽  
Residue Position

ABSTRACT The enzymatic cleavage of synthetic oxytocin and 8-lysine vasopressin by sera of women in advanced pregnancy was investigated by using paper chromatography. Following incubation of either hormone with pregnancy serum and subsequent oxidation, two molecular fractions were formed, of which one could be identified as L-cysteic acid. By contrast, oxidation of the intact cyclopeptide hormones did not lead to liberation of free L-cysteic acid. It was concluded that oxytocin and 8-lysine vasopressin were cleaved by an identical mechanism involving splitting of the peptide bond joining the tyrosine residue (position 2) to the amino-terminal halfcystine residue (position 1). Pregnancy serum »oxytocinase« and »vasopressinase« thus appeared to be one and the same enzyme.

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