Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxytocin, like insulin, stimulates glucose oxidation in normal rat adipocytes. Fat cells from homozygous Brattleboro rats that exhibit diabetes insipidus (HoDI animals) and that have a normal number of oxytocin receptors, however, are unable to respond to oxytocin in terms of glucose oxidation. We now report that in adipocytes from HoDI animals that are responsive to insulin, oxytocin was also unable to stimulate lipogenesis. In contrast, oxytocin like insulin was able to inhibit epinephrine-stimulated lipolysis in adipocytes from HoDI animals. Thus, in HoDI adipocytes, the results indicate that the receptor-effector system is only partially defective.
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PMID:Oxytocin action: lipid metabolism in adipocytes from homozygous diabetes insipidus rats (Brattleboro strain). 629 16

To study the role of the paraventricular nucleus and of neurohypophysial hormones in the control of ACTH secretion, the paraventricular nuclei (PV) of Brattleboro diabetes insipidus rats (DI) were lesioned (L) with a knife; sham-lesioned DI (S) served as controls. Four days later, the rats were stressed by ether inhalation, and blood samples were taken during and 30-40 min after stress for the determination of corticosterone. The median eminence (ME) and neural lobe (NL) were homogenized in 50 microliters of 0.1 N HCl and frozen pending bioassay of corticotropin-releasing factor (CRF). PV lesion almost abolished the corticosterone secretion to ether and reduced the ME CRF content three- to sevenfold. The NL CRF content in S was about twice that of ME, and oxytocin accounted for more than 60% of NL CRF. However, PV lesion had no effect on NL CRF activity. Low amounts of oxytocin (2 mU/ml) had no significant CRF activity but potentiated the ME CRF effect in L. The results suggest that 1) PV is one of the most important sites for CRF synthesis or CRF fiber transit in DI; 2) corticosterone secretion to ether stress is governed mainly by ME CRF; and 3) a large proportion of CRF fibers to NL probably originates outside PV.
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PMID:Paraventricular nucleus region controls pituitary-adrenal function in Brattleboro rats. 629 23

Rat pituitary neural lobe contained high concentrations of cholecystokinin-like immunoreactivity (CCK-LI). Section of the pituitary stalk resulted in loss of CCK-LI, and both lactation and replacement of drinking water with 2% saline resulted in marked depletion of CCK-LI. Rats with congenital diabetes insipidus (Brattleboro strain) had a 73% reduction in CCK-LI below the levels of hooded Long-Evans controls, where as levels in the brain were unchanged. Release of CCK-LI, labeled dopamine, and gamma-amino butyric acid in response to potassium depolarization was studied. There was a low fractional release of CCK-LI. Addition of sulfated CCK-8 (CCK-8s) to the medium enhanced the calcium-dependent potassium-stimulated release of dopamine, but basal release was unaffected. gamma-Amino butyric acid release was only poorly calcium dependent and not effected by extracellular CCK-8s. Vasopressin and oxytocin release were stimulated by electrical stimulation of the pituitary stalk, and were unaffected by the addition of CCK-8s to the medium. In vivo, however, the injection of 5 micrograms CCK-8s into the third ventricle resulted in increased plasma vasopressin concentrations.
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PMID:Localization and actions of cholecystokinin in the rat pituitary neurointermediate lobe. 632 36

This investigation has confronted some very basic questions of neurobiology and specifically deals with the neurovascular and neuroanatomical interactions that occur between graft and host following neural transplantation. Host Long-Evans rats with chronic autosomal diabetes insipidus (DI) received stereotaxic implants of normal 17 day post-coitus fetal hypothalamic fragments from the rostral (anterior) hypothalamus of normal Long-Evans pups. Following stereotaxic surgery DI hosts were killed 60 or 90 days later and their brain prepared for correlative microangiography-immunocytochemistry coupled with transmission electron microscopy. Explants were rapidly invaded by host vessels from several routes. (1) Vessels appeared to arise from portal capillaries in the underlying median eminence and (2) from adjacent vessels from the paraventricular nucleus and surrounding endocrine hypothalamus and (3) possibly from intrinsic vessels of the graft. The former remained fenestrated and established bonafide neurovascular zones in the ventral regions and in actively growing explants. Small clusters of arginine vasopressin-positive fibers and neurophysin positive neurons were noted throughout the parenchyma of explants. Despite the presence of neurosecretory neurons and neurovascular (neurohemal) zones, none of the host rats exhibited a physiological return to normal parameters of water balance. However the active growth and development of explants in the third cerebral ventricle of DI host rats coupled with emergence of neurovascular zones lends support to a potential model for analyzing the development of anatomical substrates for the central delivery of neuropeptide hormones.
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PMID:Neuronal and neurovascular integration following transplantation of the fetal hypothalamus into the third cerebral ventricle of adult Brattleboro rats. Neurological transplants: I. 633 69

We have evaluated factors, other than genetic, which might be related to the lack of an oxytocin-mediated insulinlike response (glucose oxidation; lipogenesis) in adipocytes from Brattleboro rats, homozygous for the diabetes insipidus trait (HoDI rats). The manoeuvres used in an attempt to restore the glucoregulatory responses to oxytocin in HoDI cells (increased glucose in the fat pad digestion medium; increased calcium concentration in the oxidation assay; estrogen treatment; use of [1-14C]glucose as substrate; inclusion of adenosine in the assay medium; vasopressin replacement therapy) uniformly failed to result in oxytocin activation of HoDI adipocytes. In contrast, the contractile responses of estrogenized HoDI rat uteri were indistinguishable from those of estrogenized normal rats. We conclude that the nonresponsiveness of the Brattleboro adipocytes to the glucoregulatory actions of oxytocin is not due to factors related to the conditions of the bioassay. On the other hand, in normal fat cells (from Sprague-Dawley and Long Evans rats), oxytocin responsiveness was augmented by a number of the manoeuvres mentioned above, most notably by the inclusion of either calcium (10 mM) or adenosine (10 microM) in the assay medium. Nonetheless, the maximum oxytocin responsiveness of adipocytes from Long Evans or Sprague-Dawley rats, under all conditions of assay, was still only a fraction (less than 20%) of the maximal response to insulin. The effect of adenosine on oxytocin action (increased sensitivity, without an effect on the maximum response) is in keeping with the previously observed effects of this nucleoside on the action of insulin; our results thus pointed to a new parallel in the action of insulin and oxytocin.
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PMID:Oxytocin resistance in Brattleboro rat adipocytes and comparative studies on insulin or oxytocin responsiveness in normal rat adipocytes. 636 6

This chapter has reviewed briefly the neuroanatomy relevant to the synthesis and release of AVP and OXT. Osmoregulation and baroregulation of AVP secretion has been discussed in detail, emphasizing the importance of osmotic control under normal physiological conditions. The remainder of the text has covered the two major pathophysiological disturbances of AVP secretion. In considering diabetes insipidus a pragmatic approach has been taken in the differentiation of the causes of polyuria and its treatment. A similar approach has been applied to the syndrome of inappropriate antidiuresis. Brief mention was made of the function of OXT.
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PMID:Posterior pituitary function in health and disease. 636 55

This investigation has combined microangiography, immunocytochemistry, coupled with transmission and scanning electron microscopy to discuss the neuroanatomical interactions that occur in the brains of Brattleboro rats with diabetes insipidus, following stereotaxic placement of normal fetal hypothalamic fragments into the third cerebral ventricle. Following surgical placement of 17 day post-coitus hypothalamic fragments, host rats with chronic autosomal homozygous diabetes insipidus were killed and their brains were prepared for analysis. A significant degree of explants (68%) flourished and grew in the lumen of the third cerebral ventricle of recipient hosts. Explants were rapidly invaded by host vessels from two routes. Vessels arose from the underlying mantle plexus of portal capillaries which remained fenestrated in the lower one-third of the explants and developed neurovascular (neurohemal) zones. The second source of vessels arose from bed capillaries of the adjacent paraventricular nucleus and adjacent hypothalamus. In contrast to vessels arising from the contact zone, these latter vessels remained unfenestrated. Small clusters of immunocytochemically positive neurons (neurophysin positive) were seen throughout the explants. Numerous healthy magnocellular neurons harboring numerous dense core vesicles and exhibiting multiple axosomatic and axodendritic synapses were seen throughout the neuropil of explants. Axon profiles were noted to terminate upon the abluminal basal lamina of perivascular spaces surrounding fenestrated capillaries in the lower one third of explants. None of the host animals exhibited physiological return to normal parameters of urine output, drinking behavior, and/or urine osmolarity. However the growth and development of explants in the third cerebral ventricle of DI hosts coupled with the emergence of bonafide neurovascular zones supports a potential anatomical substrate for the central delivery of neuropeptide hormones in this experimental model.
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PMID:The neuroanatomical and neurovascular organization of normal fetal hypothalamic explants in the third cerebral ventricle of Brattleboro rats with homozygous diabetes insipidus. 638 48

Brattleboro (diabetes insipidus) rats showed a delayed recovery from 6-hydroxydopamine (6-OHDA) hypotension as compared to Long Evans controls. A slight increase in circulating arginine vasopressin was noted in the 6-OHDA-treated Long Evans rats but no change in circulating oxytocin was apparent in either species. The haematocrit and plasma potassium suggested haemodilution in Long Evans rats following 6-OHDA treatment but no such changes were apparent in similarly treated Brattleboro rats. Since the major difference in Long Evans and Brattleboro rats is the latter's inability to synthesize arginine vasopressin (AVP), it is suggested that AVP may have a role in the restoration of homeostasis following 6-OHDA-induced hypotension. This conclusion is supported by (a) a delayed recovery from hypotension and (b) no change in blood concentration parameters, in the Brattleboro rat.
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PMID:Reversal of 6-hydroxydopamine-induced hypotension in Long Evans and diabetes insipidus (Brattleboro) rats. 640 2

The cardiovascular effects of intravenous and intracisternal administration of neurohypophysial peptides were compared in normal, diabetes insipidus and adrenal demedullated chloralose anaesthetized dogs. In normal dogs, intravenous lysine vasopressin (0.1 to 100 mU/kg) induced a dose-dependent increase in blood pressure with bradycardia whereas intracisternal injection (0.01 to 10 mU/kg) elicited a dose-related decrease in blood pressure but no change in heart rate. Intracisternally injected oxytocin (1 and 10 mU/kg) increased blood pressure. The central hypotensive effects of vasopressin were not observed in diabetes insipidus or adrenal demedullated dogs. In contrast, the central pressor properties of oxytocin were still observed in these two groups of animals. These results show that the central cardiovascular properties of vasopressin (but not those of oxytocin) may vary according to the hormonal state of the animals. Intracisternal vasopressin induces an hypotensive response due to a decrease in sympathetic tone and dependent on the integrity of the neurohypophysial tractus.
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PMID:The role of adrenal medulla and neurohypophysis in the central and peripheral cardiovascular effects of neurohypophysial peptides. 648 75

The vasopressin gene from normal and diabetes insipidus (Brattleboro) rats has been isolated and sequenced. Except for a single deletion of a G residue in region coding for the neurophysin carrier protein the approximately 2300 nucleotides of both genes are identical. Blot analysis of hypothalamic RNA as well as transfection and microinjection experiments indicate that the mutant gene is correctly transcribed and spliced, however the resulting mRNA is not efficiently translated.
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PMID:The mutant vasopressin gene from diabetes insipidus (Brattleboro) rats is transcribed but the message is not efficiently translated. 652 16


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