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Query: UNIPROT:P01178 (oxytocin)
 15,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The chief obstetrical problems encountered today in the prenatal evaluation of the high-risk fetus are presented. Advantages and pitfalls or recent techniques utilized in the management of the high-risk pregnancy are discussed. They include: a prenatal scoring system for identifying the high-risk population; examination of the karyotype of cells in amniotic fluid, and quantitation of alpha-fetoprotein levels in maternal plasma and amniotic fluid for the early prenatal detection of birth defects; ultrasonography for the intrauterine diagnosis of fetal growth retardation and assessment of fetal maturity; the use of maternal urinary estriol excretion, maternal plasma human placental lactogen levels and the oxytocin stress test for the early detection of fetal distress; estimation of fetal maturity by amniotic fluid analysis of lecithin or lecithin-sphingomyelin ratios, creatinine and Blue Nile fetal cell staining. Newer, still experimental, techniques (e.g., fatal breathing movements, fetoscopy, and dehydroepiandrosterone plasma clearance) are viewed in light of further possible decreases in maternal and perinatal mortality.
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PMID:Antepartum evaluation of the high-risk fetus: problems and prospects. 7 Dec 31

In eight patients undergoing chronic hemodialysis, ultrafiltration was performed for 1 h in each patient. The concentration of urea nitrogen, creatinine, ADH, cortisol, GH, prolactin and TSH was measured in plasma and the filtering solution, and the permeability of each substance was determined. The plasma concentration of ADH coincided with that of the filtering solution, and no significant difference was noted between the permeability of creating and ADH. In contrast, cortisol, GH, prolactin and TSH were not detected in the filtering solution. Chromatographic study showed that ADH in the filtering solution coincided with synthetic ADH. From a comparison of the permeability with the molecular weight, it was suggested that ADH in the blood exists in free form without binding with plasma proteins or neurophysin.
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PMID:Permeability of antidiuretic hormone and other hormones through the dialysis membrane in patients undergoing chronic hemodialysis. 91 84

Heat-stressed pregnant ewes deliver intrauterine growth-retarded lambs. Selected maternal and fetal changes were investigated during acute heat stress in order to elucidate the mechanism for this growth retardation. Uterine blood flow decreased 20 to 30% in pregnant ewes during 1 degree C increases in core temperature. The decreases were accompanied by 60 and 100% increases in serum oxytocin and antidiuretic hormone, respectively. These effects were mimicked by salt loading or injections of antidiuretic hormone or oxytocin, suggesting a role for either or both hormones in regulating uterine blood flow during pregnancy. Chronically heat-stressed pregnant ewes were delivered by Caesarean section. Their fetuses were approximately 20% smaller than thermoneutral controls. Within each pair of heat-stressed twins, one fetus weighted one-third less than its litter mate. No difference in weights were observed within the control twins. The livers and brains of the heat-stressed fetuses were disproportionate in size. The livers from the small heat-stressed twins contained only one-half the protein of the controls and one-fourth the protein of their litter mates. Muscle protein was decreased in the heat-stressed fetuses, and liver and muscle glycogen were elevated as were liver arginase, glutamate-pyruvate transaminase and muscle creatinine. These results are consistent with the following hypothesis: heat stress stimulates the release of maternal antidiuretic hormone or oxytocin, which reduces uterine blood flow and causes a shift in fetal metabolism from anabolic to catabolic pathways; one fetus of heat-stressed twins is more severely affected than its litter mate.
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PMID:Maternal endocrine and fetal metabolic responses to heat stress. 203 Jan 75

Hydrops allantois was diagnosed in two Haflinger mares with severe abdominal distension. Both mares were seven months pregnant. Abortion was induced with two injections of prostaglandin six hours apart followed by further manual dilation of the cervix and administration of oxytocin the next day. There were 90 and 95 litres of fluid, respectively, in the allantoic cavities which resembled extracellular fluid with regard to concentrations of urea, creatinine, sodium, potassium, calcium, magnesium, phosphate and chloride, but not total protein. Both fetuses had severe brain abnormalities which were diagnosed as cerebellar and cerebral hypoplasia associated with bilateral hydrocephalus internus and hydranencephaly and cerebellar aplasia, respectively. Both mares were pregnant by the same stallion, but a clear hereditary link was not found.
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PMID:Two related cases of cerebellar abnormality in equine fetuses associated with hydrops of fetal membranes. 320 93

The purpose of this study was to investigate the main renal and hormonal responses to head-down bed rest, which is currently considered a reliable experimental model for the simulation of weightlessness. Urinary output and electrolytes, plasma renin activity (PRA), aldosterone (PA), antidiuretic hormone (ADH) and immunoreactive neurophysin-I (Np) were measured in eight adult volunteers submitted to a 4-day head-down bed rest (-6 degrees) after a 24-h control period in the horizontal position (day 0). Four of the eight subjects were submitted to two 1-h periods of controlled muscular exercise (50% VO2max) from day 1 to day 4. Throughout the head-down bed rest period, urinary output remained stable, although lower than in the control period (day 0), but the urinary Na/K ratio decreased. Plasma electrolytes and osmolality, and creatinine clearance remained unchanged. There was no significant difference between exercising and non-exercising subjects. At the hormonal level, PRA and PA increased during the head-down bed rest. This increase was more pronounced in the group with exercise. At the end of the tilt period, PRA and PA were about 3 times higher than on day 1. No significant changes could be observed for ADH and Np. It is concluded that a 4-day head-down bed rest results in no apparent changes in neurohypophyseal secretory activity, and in a progressive secondary hyperaldosteronism.
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PMID:Plasma vasopressin, neurophysin, renin and aldosterone during a 4-day head-down bed rest with and without exercise. 351 79

To study the role of the antiaggregatory and vasodilatory prostacyclin (PGI2) during human delivery, serial urine samples collected from 13 women delivered vaginally and from eight delivered abdominally were assayed for 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha, a breakdown product of PGI2) by high-performance-liquid-chromatography and radioimmunoassay. In women delivered vaginally the mean urinary 6-keto-PGF1 alpha concentration was 41.9 (SE 8.3) ng/mmol creatinine, before the onset of labour and increased progressively to a maximum of 186.5 (SE 47.6) ng/mmol creatinine 2 h after delivery irrespective of the use of oxytocin and epidural analgesia. In women delivered by caesarean section under epidural anaesthesia, the urinary 6-keto-PGF1 alpha rose from 33.4 (SE 4.2) ng/mmol creatinine to 2153 (SE 314) ng/mmol creatinine 2 h after section. In both groups the increased levels had fallen by 24 h postpartum to levels below those found before delivery. In neonatal urine 6-keto-PGF1 alpha concentrations were some 12-30 times higher than those in postpartum urine. Thus, vaginal and abdominal delivery is accompanied by significant increases in maternal PGI2 release, perhaps in the myometrium and/or intrauterine tissues. This may be of significance in the regulation of fetoplacental blood flow and in the prevention of intra- and postpartum thrombosis.
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PMID:Vaginal and abdominal delivery increases maternal urinary 6-keto-prostaglandin F1 alpha excretion. 376 89

To determine the effects of fluid restriction in induced labour with oxytocin in 5% dextrose solution, maternal venous blood and fetal cord venous blood were examined in 164 mothers in induced labour and 29 mothers with a spontaneous onset of labour. After satisfactory uterine activity was induced either the oxytocin infusion was managed according to routine delivery unit practice (n = 36), or infusion rates were halved (n = 45), or quartered (n = 43), or discontinued (n = 40). Despite fluid restriction during labour the mean sodium concentration in maternal blood or cord blood had fallen to a similar extent in all four induced groups at delivery. Potassium, urea, creatinine, total protein, and albumin in maternal blood or cord blood were affected differently by induced labour as compared with sodium. The fall in sodium concentration in maternal blood was a more consistent reflection of the total volume of fluid received, mean infusion rates and cord blood sodium after infusion rates were quartered or discontinued. The incidence of hyponatraemia was 5% in mothers and 8% in infants. A comparison of hyponatraemic and normonatraemic cord blood showed no significant differences in serum bilirubin levels or red cell counts, but more hyponatraemic infants developed neonatal jaundice. It is suggested that in induced labour fluid restriction alone does not prevent hyponatraemia and neonatal jaundice.
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PMID:Oxytocin induction of labour: hyponatraemia and neonatal jaundice. 377 Feb 80

Synthetic oxytocin (OT) was infused iv in four men at 3 mU/min, and the rate was doubled every 90 min for a total of three infusion periods. The mean (+/- SEM) OT MCR was 16.4 +/- 1.7 ml/kg X min and was independent of the rate of infusion. A method for measuring OT in urine was developed using an octadecasilyl-silica column for extraction of the hormone. The extracted residue was reconstituted in potassium phosphate buffer, pH 7.4, for RIA. The minimum detectable level of OT in urine was 0.2 microU/ml (defined as a bound to free ratio of approximately 90%). The mean recovery of OT was 77 +/- 2%. The mean (+/- SEM) concentration of endogenous OT in urine was 10.2 +/- 1.4 microU/ml. Endogenous OT in urine eluted from a reverse phase high pressure liquid chromatography column as a single peak of OT immunoreactivity in the position of synthetic OT. Urinary OT excretion during infusion of synthetic OT was linearly correlated with plasma OT concentration whether calculated as microunits of urinary OT per mg creatinine (r = 0.89) or urinary OT per min (r = 0.93). Mean urinary fractional clearance of OT (OT clearance/creatinine clearance) was 3.6% renal clearance of OT (5.5 ml/min or 0.43% of MCR). Thus, OT MCR was constant over a wide range of physiological plasma OT levels and was similar to MCR in pregnant women studied previously in this laboratory. Less than 1% of OT was cleared in urine. This study defines the relationship between urinary and plasma OT during steady state infusion of physiological concentrations of the hormone and indicates that measurements of OT in urine by RIA may prove helpful for pharmacokinetic and physiological studies of OT-related events in humans.
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PMID:Clearance studies of oxytocin in humans using radioimmunoassay measurements of the hormone in plasma and urine. 379 53

1. Weanling rats fed on a synthetic diet, which was completely deficient in arginine, grew more slowly than rats fed on a similar diet which included arginine.2. No differences in the haemoglobin level or plasma protein concentration or electrophoretic pattern were found in the two groups of rats.3. The arginine-deficient rats drank less water, and excreted less urine, which was more concentrated than that of the control animals, although the solute output was reduced, and the extrarenal water losses were the same.4. The arginine-deficient animals excreted less urea, non-protein nitrogen, creatinine and total solutes. The blood urea concentration of the deficient animals was significantly higher than that of the controls, indicating that arginine deficiency had impaired the excretion of urea.5. There was no difference between the renal weights of both groups of animals when related to total body weight, nor was there a difference in the histological appearance of the kidneys.6. The amounts of arginine vasopression and oxytocin/kg body wt. stored in the neurohypophyses of both arginine-deficient and control animals were the same.
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PMID:The effects of arginine deficiency on the water and solute metabolism of weanling rats. 591 5

1. When 5-hydroxytryptamine creatinine sulphate is injected subcutaneously in a dose of 2 mg into mice during the second half of pregnancy, the foetuses die within 1 hr. The mode of action of 5-hydroxytryptamine (5-HT) in producing this effect has been studied.2. It has been demonstrated that this is not a direct toxic effect of 5-HT. Very little passes through the placenta into the foetus, and after the injection of much larger amounts directly into the foetus no lethal effect was observed.3. It was shown that 5-HT had little effect on uterine motility in vivo, and that the much larger contractions produced by oxytocin did not produce any effect on the foetus.4. No constriction of the umbilical vessels was produced by 5-HT injected into the mother, nor did the local application of 5-HT to the cord produce any effect.5. The administration of 5-HT to the mother markedly reduced the passage of (22)Na from the maternal circulation into the placenta and foetus. This was accompanied by a reduction in the blood supply to the placenta from a normal value of 87 mul./min/g to 4 mug/min/g.6. It is suggested that the effect of 5-HT in producing foetal death is a consequence of the reduction in the transfer function of the placenta.
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PMID:Analysis of actions of 5-hydroxytryptamine in pregnancy. 596 41


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