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At least 19 recordsLinked to original sources
PubMed1979

Identification of neurophysin-like proteins in the posterior pituitary gland of the chicken (Gallus domesticus).

Chicken posterior pituitary tissue was partially fractionated by extraction with 0.1 M HCl followed by gel exclusion chromatography. Two fractions, B and C, bound oxytocin. Two components of fraction B and at least 1 component of fraction C had properties characteristic of mammalian neurophysins: they appeared to be synthesized in the hypothalamus, were depleted upon osmotic stress, were rich in residues of cysteine and the 2 components of B bound to [8-lysinel]-vasopressin coupled to Sepharose.

Amino Acids↗
PubMed1977

Distribution of corticotrophin releasing factor activity within the hypothalamic-pituitary complex of rats and cattle.

An assay system involving cultured rat adenohypophysial cells from either intact or adrenalectomized donors was used to study the distribution of corticotrophin releasing factor (CRF) activity in the hypothalamic-pituitary complex of rats and cattle. In the rat hypothalamus, CRF activity was most concentrated in the median eminence, but CRF was present in the stalk and the posterior pituitary gland in much higher concentrations than in the median eminence in both species. The dose--response slopes for the median eminence, stalk and pars nervosa of the posterior pituitary gland were parallel to each other, suggesting a qualitative similarity between the CRF activity in these tissues. Rat posterior pituitary glands may also contain another CRF component which has a much flatter dose--response curve, but is detectable in smaller quantities of posterior pituitary tissue than is the other type of CRF.

Adrenalectomy↗
PubMed1977

Exocytosis: the common release mechanism of secretory granules in glandular cells, neurosecretory cells, neurons and paraneurons.

Exocytotic granule release in glandular cells (exocrine and endocrine), neurosecretory cells, neurons and paraneurons was discussed. Attention was focused on the neurosecretory terminals in the mammalian posterior pituitary gland and adrenomedullary cells. The concept of "exocytosis-vesiculation sequence" proposed by Douglas and Nagasawa was introduced. This theory states that the exocytotic release of secretory granules was followed by the mechanism of granule membrane recovery; this process occurred at the bottom of the exocytotic pit in the form of coated microvesicles. Experimental results were presented which substantiated the theory for the transformation of coated microvesicles into smooth microvesicles. The origin and the nature of long enigmatic "synaptic vesicles" in the posterior pituitary gland was thus explained. The exocytotic release probably operates as the general and perhaps sole mechanism of granule release in a variety of glandular cells, neurosecretory cells, neurons and paraneurons.

Adrenal Medulla↗
PubMed1976

[Neurophysins of Mammals: evolution and biological signification].

Neurohypophysial hormone-Neurophysin complexes have been prepared from posterior pituitary glands of Artiodactyla (ox, sheep, pig), Perissodactyla (horse) and Cetacea (whale), by fractionated salt precipitation. The components have been separated by molecular sieving in 0.2 M acetic acid and neurophysins have been purified by ion-exchange chromatography on DEAE-Sephadex A-50. Two types of neurophysins, MSEL-neurophysins and VLDV-neurophysins, can be distinguished according to the amino acid residues in positions 2, 3, 6 and 7. MSEL-neurophysins of sheep, ox and pig have been characterized by the amino acid sequence. Ovine and bovine MSEL-neurophysins are nearly identical (one substitution out of 95 residues) and porcine MSEL-neurophysin is very similar (four substitutions and an apparent 3-residue C-terminal deletion). The biological function of neurophysins might be the carriage of neurohypophysial hormones but in this respect, each type of neurophysin is not clearly specific for a given hormone. On the other hand, each neurophysin might share a common precursor with a neurohypophysial hormone, the two parts remaining associated after cleavage. However, in the sheep posterior pituitary gland, the molar proportions of the two types of neurophysins, oxytocin and arginine vasopressin, are not equal, MSEL-neurophysin being more abundant than the other components. If a common precursor exists, neurophysins and neurohypophysial hormones are not merely produced by a simple cleavage mechanism.

Amino Acid Sequence↗
PubMed1979

Bovine neurophysin lipid complex. Their isolation, characterization and reaggregation.

A lipid-containing neurophysin fraction was isolated and purified from bovine posterior pituitary glands by acid extraction and affinity chromatography on a heparin-Sepharose 4B column. This lipid-rich fraction was found to be composed of noncovalent aggregates of neurophysin proteins and phospholipids such as phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl serine and sphingomyelin. The lipid-containing neuophysin was delipidated by treatment with choloform-methanol. The resultant apoproteins were characterized as bovine neuroions were developed for the reaggregation of purified bovine neurophysin-I and -II with lipids extracted from bovine posterior pituitary and hypothalamus and with synthetic lecithin. The resultant neurophysin lipid complexes have been shown to band upon isopycnic centrifugation at densities different from those of the respective purified bovine neurophysins.

Animals↗
PubMed1975

Molecular weights of adrenocorticotropic hormone in extracts of anterior and intermediate-posterior lobes of mouse pituitary.

The molecular weight of the adrenocorticotropic hormone (ACTH) activity in extracts of the separated anterior and intermediate-posterior lobes of the mouse pituitary was determined by gel filtration in guanidine-HCl. Following dilution or removal of the guanidine-HCl, ACTH activity was quantitated by both radioimmunoassay and bioassay. Extracts of the intermediate-posterior lobe contain approximately a tenth as much ACTH activity as extracts of the anterior lobe. In extracts of both the anterior and the intermediate-posterior lobes, about half of the immunological ACTH activity is similar in size to porcine ACTH (molecular weight 4000--5500). Two higher molecular weight forms of ACTH account for the remainder of the ACTH activity. About 40% of the immunological ACTH activity in anterior lobe extracts has a molecular weight of 6500--9000. Extracts of both the anterior lobe and the intermediate-posterior lobe contain ACTH activity with a molecular weight of 20,000--30,000. While this 20,000--30,000 molecular weight ACTH accounts for only 5% of the immunological ACTH activity in the anterior lobe extracts, it accounts for half of the immunological ACTH activity in extracts of the intermediate-posterior lobe. Extracts of an ACTH-secreting mouse pituitary tumor cell line (AtT-20/D-16v) contain the same three molecular weight forms of ACTH. Each of the three molecular weight forms of ACTH has a characteristic ratio of biological ACTH activity to immunological ACTH activity, independent of the source of the material (anterior lobe, intermediate-posterior lobe, or mouse pituitary tumor cell line).

Adrenocorticotropic Hormone↗
PubMed1976

Ultrastructural studies on the localization of neurohypophysial hormones and their carrier proteins.

Neurophysin, vasopressin and oxytocin were localized in different portions of the supraopticohypophysial tract (SHT) using the unlabeled antibody enzyme technique at the ultrastructural level. In vasopressin-positive supraoptic perikarya, vasopressin and neurophysin were present in all neurosecretory granules. Within the zona interna of the median eminence, vasopressin and neurophysin were present in two populations of axons, one with granules of 1300-1500 A and one with granules of 900-1300 A. Following exposure of thin sections of median eminence to antiserum to neurophysin, reaction products were present in granules and in the extragranular cytoplasm in the axons with larger granules; in all other cases reaction product was confined to the granules. Vasopressin-positive fibers were also presented in large numbers of the zona externa of the median eminence and many terminated on the pituitary primary portal plexus. A few oxytocin fibers were present on the portal capillaries in the infundibular stalk. In the posterior pituitary all axon profiles were neurophysin positive. Neurophysin was present as both a granular and cytoplasmic pool. Vasopressin-containing axons account for 90% of the neuronal elements in the posterior pituitary and oxytocin for the remaining 10%. Findings on the subcellular distribution of these peptides are related to current theories on transport and release of neurohormones.

Animals↗
PubMed1979

Development pharmacokinetics of the posterior pituitary hormones.

Arginine vasotocin, arginine vasopressin, and oxytocin play a critical role in the stimulation of labor and delivery and in salt and water homeostasis in the newborn infant. The authors present information on their chemistry, secretion, and metabolism, and discuss the clinical effects upon target organs of their presence or absence.

Animals↗
PubMed1979

Neurosecretory bodies within the median eminence in association with pituitary tumours.

During necropsy the pituitary stalk is usually deliberately divided and the median eminence is separated from the posterior pituitary. In a series of 133 necropsies the brain was removed in a manner that preserved the integrity of the neurohypophysis and allowed histological examination of the entire neurohypophysis and the juxtaposed adenohypophysis. Neurosecretory bodies were found within the neurohypophysis in 2 patients,and in both microadenomas were found within the adenohypophysis. 2 other patients had larger tumours within the adenohypophysis but had no abnormalities within the neurohypophysis.

Adenoma, Chromophobe↗
PubMed1977

[Cerebral tumors of primitive germinal origin].

The authors attempt to justify the term cerebral tumour of primitive germinal origin from four of their own cases and a review of the literature. They emphasise the specific features. The tumours are more common in boys and involve the pineal, the walls of the third ventricle, the hypothalamus and the posterior pituitary. Several histological types may be distinguished by the degree of differentiation but the stromal reaction, which is partly responsible for the symptoms, is always present. The clinical course of the illness is biphasic. The first is manifest by endocrine disorders and is of relatively long duration. Water homeostasis is always affected and may be associated with other hypothalamic disorders. In the second phase, neurological symptoms and raised intracranial pressure appear. Surgical removal is not always possible, but radiotherapy improves the outlook.

Adenoma↗
PubMed1977

Localisation of gonadotropin releasing hormone (GRH) in the forebrain and neurohypophysis of the trout (salmo gairdneri). An immunofluorescence study.

The double antibody immunofluorescence technique was applied to serial coronal and sagittal sections of the brains of the trout, Salmo gairdneri, using an antibody against mammalian LH-RH. Immunoreactive material was found in small perikarya, situated at both sides of the ventriculus communis in the area dorsalis pars medialis of the telencephalon. The axons of these perikarya, also containing immunoreactive material, do not form a tract, but run diffusely in a caudo-ventral direction towards the pituitary stalk. The ending of these fibres has not yet been established.

Animals↗
PubMed1979

Induction of maternal behavior in virgin rats after intracerebroventricular administration of oxytocin.

Oxytocin produces uterine contractions and milk ejection, functions related to parturition and nuturing. Studies were conducted to determine if this peptide, native to the brain and the posterior pituitary gland, plays a role in the induction of maternal behavior. Intact virgin female rats were given 0.4 mug of oxytocin, 0.4 mug of [Arg(8)]vasopressin, or saline through lateral ventricular cannulae. Forty-two percent of intact rats receiving oxytocin displayed full maternal behavior towards foster pups. None of the saline- or vasopressin-treated animals displayed full maternal behavior. Criteria in five behavioral categories had to be fulfilled by an animal within 2 hr of injection for its behavior to be considered fully maternal. When partial maternal responses were considered, oxytocin was significantly more effective than saline and marginally more effective than vasopressin. Five animals responding fully maternally after oxytocin injection were allowed to stay with pups for 10 days. All five continued to display full maternal behavior during this time. Nearly all animals that responded fully maternally to oxytocin injection were in the last day of diestrus or in proestrus or estrus. This suggested that elevated or recently elevated levels of estrogen may be necessary for the induction of full maternal behavior by oxytocin. Twenty-seven virgin female rats were ovariectomized and given either 100 mug of estradiol benzoate per kg in oil subcutaneously or oil alone immediately after operation. Forty-eight hours later, all animals received 0.4 mug of oxytocin intracerebroventricularly. Eleven of 13 estrogen-primed animals became fully maternal; none of 14 nonprimed animals became fully maternal.

Animals↗