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PubMed1981

Bovine hypothalamic poly(A)-rich RNA-directed synthesis of a common precursor to the nonapeptide arginine vasopressin and neurophysin II. Immunological identification and tryptic peptide mapping.

The common precursor to arginine vasopressin (AVP) and neurophysin II (NpII) has been synthesized in a reticulocyte lysate system directed by bovine hypothalamic poly(A)-rich RNA. The precursor, identified with antibodies raised against neurophysin II and arginine vasopressin, has an apparent Mr of 21 000 (21 k). The specificity of the immune reaction has been shown by competition experiments using excess amounts of a variety of unlabeled peptides. With anti Np II, but not with anti AVP, a second neurophysin precursor with an apparent Mr of 18 000 (18 k) has been identified. Comparison of the tryptic maps obtained from the 21 k and 18 k precursors shows that both products give rise to the four [35S]cysteine-labeled neurophysin II-peptide fragments; however, only the 21 k yields an AVP-like tryptic peptide, identified with antibodies raised against AVP. The possible implications of the two precursors, one consisting of AVP and Np II, the other of Np II only, are discussed.

Animals↗
PubMed1981

Essential hypernatraemia, antidiuretic hormone and neurophysin secretion: response to chlorpropamide.

An adolescent boy with essential hypernatremia, absent corpus callosum, mental retardation, hypodipsia, and partial diabetes insipidus with "inappropriate" ADH regulation and secretion was studied regarding factors controlling ADH and neurophysin release. Persistent hyperosmolality was noted while on 100 mEq sodium intake daily. Endogenous vasopressin activity was demonstrated after prolonged water deprivation. Hypertonic saline infusion produced increased volumes but dilute urine. Aqueous pitressin increased urinary osmolality, decreased serum osmolality, urine flow rate, and free water clearance. Stable water diuresis was induced by water loading and on normal saline infusion. Nicotine-stimulated neurophysin remained unexpectedly low and below the level of detectability when sampled during the physiologic studies, whereas oestrogen-stimulated neurophysin was elevated during oestrogen stimulation, water loading, and orthostasis procedures. Plasma vasopressin was suppressed with water loading but remained suppressed 90 min after tilt table testing. These data indicate impairment of the osmoreceptor mechanism: however, since the patient had a normal response of oestrogen-stimulated neurophysin, that part of the neurohypophysis appears intact. Chlorpropamide was effective in alleviating the hyperosmolar state acutely and maintained normal osmolar concentrations during two years of therapy.

Adolescent↗
PubMed1988

Presence of pro-vasopressin mRNA, neurophysin and arginine vasopressin in mouse anterior pituitary cells and the AtT-20 corticotrophic tumour cell line.

Pro-vasopressin mRNA, neurophysin and arginine vasopressin (AVP) were assayed in the mouse anterior pituitary gland, in mouse anterior pituitary cells in culture and in the AtT-20 corticotrophic tumour cell line. Northern blot analysis revealed the presence of an approximately 700 base pair pro-vasopressin mRNA in anterior pituitary and AtT-20 cells. Neurophysin, identified by immunoblots, and AVP, identified by high-performance liquid chromatography and cross-reactivity with AVP antiserum, were detected in anterior pituitary cells and AtT-20 cells. Immunocytochemical staining with anti-neurophysin showed that approximately 40-45% of the dissociated anterior pituitary cells in culture and greater than 95% of the AtT-20 cells were stained. Anterior pituitary cells in culture and AtT-20 cells had a basal level of release of AVP in the 0.01-0.1 nM range. These results indicate that anterior pituitary cells and AtT-20 cells have the ability to synthesize and process pro-vasopressin to AVP and neurophysin, endogenously.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1977

Release of neurophysins I and II during and after parturition in cows.

Bovine neurophysin I and neurophysin II (bNpI and bNpII) have been assayed by radioimmunoassay in the jugular venous blood of cows during parturition. In general, low bNpI levels were detected on the day before labour began and during the first stage of labour. Neurophysin I was present in appreciable quantities in blood taken during the second stage of labour and in most cows the concentrations rose to a maximum during the expulsive stage. After delivery, the concentration of bNpI in the blood diminished. This pattern of release is similar to that reported for oxytocin at parturition in cows. As with bNpI, maximum levels of bNpII occurred during the expulsive stage of labour in some animals. In others, bNpII concentrations were very low or absent. Low concentrations of bNpII were found at the other stages of labour. Examination of the results from individual animals indicated that the release of the two neurophysins can be independent.

Animals↗
PubMed1982

Oxytocin, vasopressin and neurophysins in the hypothalamo-neurohypophysial system of the human fetus.

The content of vasopressin, oxytocin and their related neurophysins was measured in the hypothalamus and pituitary gland of mid-trimester human fetuses. Vasopressin was present in both tissues approximately 3-4 weeks before oxytocin. The levels of the hormones in the pituitary gland increased 1000-fold over the next 3-4 months. During this time, the very high vasopressin/oxytocin ratio gradually deceased but did not reach unity in the period studied. In contrast, both the vasopressin-associated neurophysin and the oxytocin-associated neurophysin appeared in the pituitary gland at the same gestational age and showed the same exponential increase with fetal age. Lower levels of the neurophysins and the nonapeptides were found in the hypothalamus and the levels increased more slowly with fetal age. Our results suggest that the high vasopressin/oxytocin ratios observed in fetal life are due to differences in the rate of maturation of the hormone precursor, rather than to differences in the rate of de-novo synthesis.

Female↗
PubMed1992

Binding and spectroscopic properties of ostrich neurophysins. Probing the role of residue 35 at the monomer-monomer interface.

Binding and spectroscopic properties of ostrich neurophysins were examined with emphasis on the behavior of Tyr-35, a residue that provides a potential probe of the monomer-monomer interface and of allosteric interrelationships between this region and the binding site. Mesotocin-associated ostrich neurophysin was found to bind oxytocin and related peptides with affinities comparable to the mammalian proteins, but induced a significantly different optical activity in bound peptides than the mammalian proteins. Gel-filtration studies indicated higher dimerization constants for the ostrich neurophysins than for the bovine neurophysins. Consistent with this, Tyr-35 was found to be largely buried, as monitored by tyrosine titration and lack of reactivity towards tetranitromethane under non-denaturing conditions. Reaction of Tyr-35 of the mesotocin-associated protein with tetranitromethane under denaturing conditions, followed by refolding, allowed isolation of an active product with an altered interface region as partially evidenced by its titration properties and consistent with its markedly altered CD spectrum. Comparison of the CD spectra of the modified and native proteins and analysis of pH effects indicated the contribution of Tyr-35 to an unusual 237 nm band in the mesotocin-associated protein. Small shifts in the 350 nm CD band of nitrated Tyr-35 on binding peptide and apparent effects of nitration on the induced optical activity in bound peptide provided evidence of at least weak structural communication between Tyr-35 and the binding site. However, no significant effect of nitration on binding affinity was observed, suggesting that, in the mesotocin-associated protein, the region around residue 35 is not a stringent modulator of the thermodynamic behavior of the binding site.

Amino Acid Sequence↗
PubMed1978

Design of a photoaffinity label for the hormone binding site of neurophysin.

The photolabile peptide, L-methionyl-L-tyrosyl-p-azido-L-phenylalaninamide, was synthesized by solution methods. This peptide, as well as the analogous species containing tritiated methionine, were found to bind reversibly and specifically, in the dark, to bovine neurophysin II. The dissociation constant, stoichiometry, and pH-dependence of this noncovalent interaction are typical of those properties for hormone (oxytocin) and hormone-like ligand binding to neurophysin II. Under photolytic conditions, methionyl-tyrosyl-p-azidophenylalaninamide causes irreversible inhibition of the noncovalent ligand binding activity of neurophysin II. This inactivation was achieved to the extent of about 90%. Both the dark and light (photolytic) interactions of the photolabile peptide with neurophysin II indicate its reaction at the hormone binding site of the protein and thus its potential use to identify amino acid residues at this site by covalent photoaffinity labelling.

Animals↗
PubMed1976

Binding studies of polypeptide hormones to bovine neurophysins.

Experimental binding isotherms of [9-glycinamide-1-(14)C]oxytocin and [9-glycinamide-1-(14)C]arginine vasopressin to purified neurophysins I and II at pH = 4.4, 5.4, 6.5, 7.4, and 8.5 and 6 degrees, 22 degrees, and 37 degrees in aqueous buffers are reported. For purposes of comparison, binding isotherms for [4-glycine-1-(14)C]oxytocin to neurophysin II and I in aqueous buffer, and [9-glycinamide-1-(14)C]oxytocin to neurophysin II in dimethylsulfoxide under selected conditions are also reported. A brief discussion of the interpretation of binding isotherms is entered into and apparent binding constants are derived. The results indicate that the interpretations presented in the literature up to now are much too simple. There are, in contrast, multiple binding sites of oxytocin and vasopressin to the neurophysins and large temperature dependences of the number of sites and their binding constants. We find, in fact, that at 37 degrees the binding of neurohypophysial hormones to the supposed storage proteins is rather weak even at the pH of maximum binding.

Amino Acids↗
PubMed1983

Human neurophysins in carcinoma of the lung: relation to histology, disease stage, response rate, survival, and syndrome of inappropriate antidiuretic hormone secretion.

At diagnosis, 65% of 103 patients with small cell carcinoma of the lung were found to have elevated plasma concentrations of vasopressin-associated human neurophysin (VP-HNP), oxytocin-associated human neurophysin (OT-HNP), or both, which were thought to be related to tumor secretion of these proteins. The remainder of patients were designated as nonsecretors (24%) or possible secretors (11%), depending upon plasma concentration of the neurophysins prior to therapy. There was a significantly higher percentage of secretors among patients with extensive disease (82%) than among those with limited disease (40%) (P = 0.001). However, within each stage group, there was no correlation between secretory status and response to therapy, survival, or histologic subtype. In addition, patients who initially were nonsecretors or possible secretors maintained this status throughout the course of disease remission and subsequent relapse. These findings suggest the possibility of biochemical differences between tumors which present as limited disease and those which present as extensive disease. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) was infrequent in limited disease but was present in 33% of patients with extensive disease. SIADH was not seen without VP-HNP elevation; however, with extensive disease, 49% of patients with elevated VP-HNP had SIADH. In contrast, elevated plasma concentrations of the neurophysins were seen in only 19.6% of 56 patients with non-small cell carcinoma of the lung. The levels were in general lower than those in patients with small cell carcinoma and were seen at approximately equal frequencies in each major cellular subtype.

Adenocarcinoma↗
PubMedDate not supplied

[The neurophysins (author's transl)].

The neurophysins are the carriers of oxytocin and antidiuretic hormone (ADH) along the hypothalamo-neurohypophyseal tract. They are liberated when the hormones are released; their radioimmunoassay which are methodologically more simple than that of the active nonapeptides can be used in clinical practice. Moreover, the separate assay of each major neurophysins bring a specific index of the release of each hormone. The radioimmunoassay for circulating neurophysins appears to be useful for the differential diagnosis of polyuria, water retention and hypothalamic disease. The neurophysins are however devoided of any antidiuretic or oxytocic properties and their half-lives differ slightly from that of circulating hormones: therefore a basal level or values obtained in the course of an inhibitory test must be cautiously interpreted.

Animals↗
PubMed1993

Morphometric evaluation of neurophysin-immunoreactivity in the human brain: pronounced inter-individual variability and evidence for altered staining patterns in schizophrenia.

The neurohypophyseal peptides vasopressin and oxytocin have a variety of well documented behavioural effects. Accordingly, terminals and receptors that respectively contain or bind these peptides have been identified throughout the central nervous system (CNS) in experimental animals. In this study we have mapped the distribution of neurophysin I and II-immunoreactive structures in the human CNS. Neurophysins are portions of the precursor proteins for vasopressin and oxytocin, and are found specifically in structures that contain these peptides. In addition, we have quantitatively compared neurophysin neurons and fibers in the brains of individuals with no history of neurologic or psychiatric abnormality, and in brains of patients dying with psychotic illness categorized as schizophrenia. These latter brains were collected prior to the advent of pharmacologic treatment and were available from the Vogt collection. Our findings show wide variations of morphometric values obtained for neurophysin-stained structures in different CNS regions in normal subjects, but provide evidence for abnormal values in certain brain areas in untreated schizophrenia, in the hypothalamic paraventricular nucleus, internal pallidal segment and substantia nigra. These findings suggest that the function of vasopressin and/or oxytocin may be disturbed in these brain regions in schizophrenia. Further investigation will be required to establish whether these differences contribute to, or are a consequence of the disease mechanism.

Adult↗
PubMed1991

Improvement in depressive illness is not associated with altered release of neurophysins over a course of ECT.

The hypothesis that the release of vasopressin-associated neurophysin (hNpI) or oxytocin-associated neurophysin (hNpII) is modified by a course of electroconvulsive therapy (ECT) was tested by the measurement of serum neurophysins before and after the first and last ECTs given to 17 unipolar depressed patients. Neither basal nor ECT-induced neurophysin release changed between the first and last ECTs. Data from the present study were combined with data from a previous published study to provide a sample of 29 unipolar depressed patients. In this extended sample, the release of hNpII after the first ECT was significantly correlated with improvement in symptoms of depression over a course of ECT as measured by the Hamilton Rating Scale for Depression and the Montgomery-Asberg Depression Rating Scale.

Adult↗
PubMed1967

The composition of crystalline complexes of neurophysin-M with [8-arginine]-vasopressin and oxytocin.

Neurophysin-M, a methionine-containing protein that is the major constituent of neurophysin, has been crystallized as complexes with [8-arginine]-vasopressin. Three moles of vasopressin alone or 2 moles of vasopressin together with 1 mole of oxytocin are bound/mole of protein. An amorphous complex of the protein with oxytocin alone contains 2 moles of the hormone/mole of protein. Deamino-[8-arginine]-vasopressin, a highly active basic analogue of vasopressin, is not bound by neurophysin. The primary amino group of both vasopressin and oxytocin is necessary for binding with neurophysin.

Journal Article↗
PubMed1970

Studies on the chemical modification of the tyrosine residue in bovine neurophysin-II.

1. Bovine neurophysin-II contains 1mol of tyrosine residue/10000g of protein. This residue could be readily nitrated with tetranitromethane. On hydrolysis and amino acid analysis 1mol of 3-nitrotyrosine was found/10000g of protein. Starchgel electrophoresis at pH8.5 showed that nitration had converted the native protein into a single, more acidic species. The increase in acidity was consistent with the observed fall in pK of the tyrosine hydroxyl from 9.2 in native neurophysin to 7.3 in the nitrated protein. Further, the absence of any intermediate species, even under conditions of minimum substitution, confirmed that the molecular weight of the monomer is 10000. 2. O-Acetylation of the tyrosine residue was carried out with N-acetylimidazole, in conjunction with the reversible blocking of amino groups by citraconylation. The degree of O-acetylation, determined spectroscopically, was 0.9mol of O-acetyltyrosine/10000g of protein. 3. The hormone-binding ability of modified protein was tested by equilibrium dialysis and was found to be unchanged by either nitration or O-acetylation of the tyrosine residue. 4. Interaction of neurophysin-II and [8-arginine]-vasopressin gave rise to a characteristic difference spectrum with a peak at 286.8nm and shoulder at 279.6nm. Part of this hyperchromicity is thought to result from entry of the tyrosine residue at position 2 in the hormone into the hydrophobic environment of the binding site. With nitrated neurophysin-II a second peak appeared at 436nm, showing that the tyrosine of the protein is also perturbed. The very large red shift (84nm) in this region suggests that the 3-nitrotyrosyl residue not only enters a more hydrophobic environment on protein-hormone interaction, but is caused to ionize more fully by the approach of some positively charged group.

Alkanes↗
PubMed1970

Optical activity of bovine neurophysins and their peptide complexes in the near ultraviolet.

Circular dichroism studies of the bovine neurophysins in the near ultraviolet show a strong negative band at 280 nm and a strong positive band at 248 nm, both of which are attributable almost exclusively to disulfide transitions. The ellipticities per disulfide bond of the unresolved bands in neurophysin-II are -2900 deg cm(2)/decimole and +2300 deg cm(2)/decimole at 280 nm and 248 nm, respectively. Binding of oxytocin, vasopressin, or the peptide S-methyl-L-cysteinyl-L-tyrosyl-L-phenylalanine amide lead to large changes in optical activity in the near and far ultraviolet. Of these circular dichroism changes above 290 nm are attributed to changes in the optical activity of neurophysin disulfides, while changes elsewhere are more generally ascribed to changes in either disulfide, tyrosine, or peptide bond transitions. Optical rotatory dispersion studies show that calcium ion, at concentrations of 0.01 M, has only trivial effects on the affinity of bovine neurophysins for oxytocin.

Animals↗
PubMed1969

The molecular dimensions of porcine neurophysin and some thermodynamic parameters of the reaction with lysine vasopressin.

1. The molecular weight of porcine neurophysin was estimated by molecular sieve chromatography and by analytical ultracentrifugation and was found to be in the order of 13,000.2. Internal evidence for the homogeneity of the preparation of neurophysin with respect to molecular weight was obtained in the ultracentrifugation experiments.3. The frictional ratio of neurophysin was 1.1 which suggests that the molecular form of the protein approximates to a sphere.4. The molecular weight and frictional ratio were not affected by temperature change (10-34 degrees C) or by twofold change in protein concentration.5. The binding of [(14)C]lysine vasopressin to porcine neurophysin was studied at 0, 27 and at 45 degrees C, and double reciprocal plots of the binding were shown to be curvilinear at 27 and at 45 degrees C and rectilinear at 0 degrees C.6. Concordant estimates for maximum binding capacity were obtained by extrapolations from the data at 27 and 45 degrees C by applying two independent empirical methods of approximation; these agreed with the estimate obtained by extrapolation of the straight line, fitting data obtained at 0 degrees C, being approximately 1 mole lysine vasopressin per 13,000 g protein.7. The association constant and thermodynamic parameters of the reaction were estimated for near saturation conditions. The reaction is entropy driven.8. The binding of lysine vasopressin was found to be dependent on protein concentration. No dependence of oxytocin binding on protein concentration was apparent.

Animals↗
PubMed1979

The distribution of oxytocin- and neurophysin-stained fibers in the spinal cord of the rat and monkey.

Immunohistochemical methods have been used to describe the distribution of neurophysin I- and oxytocin-stained fibers in the spinal cord. In albino rats of either sex, such fibers descend through the dorsal part of the lateral funiculus to the caudal end of the cord. Fibers leave the lateral funiculus to innervate the marginal zone of the dorsal horn at all levels, and the intermediolateral column at thoracic, lumbar and sacral levels. Some fibers course medially through the intermediate gray to end in the central gray, which is innervated at all levels, and also appears to be innervated by fibers descending in the central gray itself. A semiquantitative analysis shows that the density of terminal fields in the intermediolateral column, marginal zone, and central gray varies significantly at different levels. The intermediolateral column is preferentially innervated between T1-T3, T9-T11, and T13-L2. The nucleus intercalatusspinalis and the dorsal commissural nucleus (between T13 and L2), both of which contain preganglionic neurons, are densely innervated. In the monkey (Macaca fascicularis), neurophysin I- and oxytocin-stained fibers descend through the lateral funiculus to the filum terminale, where some of them enter the pia-arachnoid surrounding the filum. The intermediolateral column is not innervated between T1-T3, is sparsely innervated at sacral levels, and is moderately innervated between T4 and L3; the greatest density of fibers occurs at L3. At most levels, few if any fibers are found in the central gray and marginal zone; the central gray is sparsely innervated between T8 and L2 at S2, and between Co3-Co6, and the marginal zone contains a small number of fibers in the region of S2 and Co6. Neurophysin I- and oxytocin-stained fibers were also found in the intermediolateral column, marginal zone, and central gray of homozygous Brattleboro, spontaneously hypertensive, and Egyptian sand rats. The results suggest that the paraventriculo-spinal pathway is particularly related to specific groups of sympathetic and parasympathetic preganglionic neurons, and to the marginal zone, whick is involved in the relay of ascending nociceptive information through the spinothalamic tract.

Animals↗
PubMed1981

Immunohistochemical analysis of magnocellular elements in rat hypothalamus: distribution and numbers of cells containing neurophysin, oxytocin, and vasopressin.

A cell-by-cell analysis of the magnocellular elements in hypothalami of fifty Long-Evans (normal) and Brattleboro (diabetes insipidus) rats was done using the unlabeled antibody enzyme technique (PAP) with primary antisera directed against oxytocin (OXY), vasopressin (ADH), and the neurophysins. The magnocellular neurons of the hypothalamus were found in the supraoptic (SON), paraventricular (PVN), and anterior commissural (ACN) nuclei, a number of accessory nuclei, and as individual cells in the anterior hypothalamic area. SON was divided by the optic tract into the principal part and retrochiasmatic SON. In retrochiasmatic SON a majority of the cells contained vasopressin. Within the principal part of SON oxytocin-producing cells tended to be found rostrally and dorsally, while the vasopressin cells were more common caudally and ventrally. PVN was divided into three subnuclei, the medial, lateral, and posterior subnuclei, on the basis of cellular morphology and peptide content. The magnocellular cells of the medial and lateral PVN were closely packed together and nearly round, while those of posterior PVN were more separated and fusiform in shape with their long axis running in a medio-lateral direction. Medial PVN consisted primarily of oxytocin-producing cells, while lateral PVN was formed by a core of vasopressin-producing cells with a rim of oxytocin cells. Posterior PVN contained largely oxytocin-producing cells. Both ADH and OXY cells were found in the accessory nuclei. In the Long-Evans rat the SON had, on the average, 1443 OXY and 3236 ADH cells; the PVN had 1174 OXY and 976 ADH cells; and the accessory magnocellular groups in the hypothalamus (including the ACN) had 1286 OXY and 552 ADH cells. The Brattleboro strain animal had similar numbers of cells in these nuclei. (The cells which contain ADH in normal animals were identified in the Brattleboro rat as large, neurophysin-negative cells.) Thus, a large fraction of the magnocellular oxytocin- and vasopressin-producing cells in the rat were located outside of the PVN and SON. One accessory cell group in particular, ACN, had 616 OXY cells, or about 50% as many as PVN. In each nucleus the sum of the numbers of OXY and ADH cells was approximately the number of neurophysin cells.

Animals↗