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PubMed1996

[The side effects of the prevention of blood loss in the placental period].

On the base of 192 retrospective and 144 prospective cases are evaluated the side of routine prophylactic of the blood loss at the third period of labor. The control group consist of 50 labouring women with expective management of placental period. In normotensive women the methergine does not increase the blood pressure. The use of oxytocic drugs after the delivery of the head shorten the time of placental separation but make more difficult the cord traction method for the delivery of the placenta. The active management of the placental period decrease the rate of instrumental revision of the uterine cavity and the supplemental administration of oxytocic in the early postpartum period. This investigation confirms and justify the routine use of oxytocic after the delivery of the head as a prophylactic of the blood loss in the placental period.

Analysis of Variance↗
PubMed1997

Misoprostol: preventing postpartum haemorrhage.

Postpartum haemorrhage is an important cause of maternal mortality and morbidity. In the developing world, it is estimated to account for 28% of maternal deaths. Evidence suggests that active management of the third stage of labour using oxytocics, significantly reduces the risk of PPH. Oxytocics are not always used in the developing world, due to storage problems, mode of administration and associated side-effects. Research using misoprostol, a prostaglandin, suggests that it may be effective in the prevention of PPH. It is given orally, does not require refrigeration and has few side-effects. Further research is planned, if misoprostol is found to be an acceptable alternative to other oxytocic agents, then it may be instrumental in reducing world wide deaths from PPH.

Developing Countries↗
PubMed1998

Rectal misoprostol in the prevention of postpartum hemorrhage: a placebo-controlled trial.

OBJECTIVE: This study investigated the effectiveness of rectal misoprostol in preventing postpartum hemorrhage. STUDY DESIGN: In a randomized, placebo-controlled study, 550 women were randomly allocated to rectally receive 400 microg misoprostol or nonidentical placebo after normal vaginal delivery. Any excessive bleeding was actively managed with conventional oxytocic agents. Blood loss was measured directly. RESULTS: The baseline variables were similar. Blood loss of > or = 1000 mL occurred in 4.8% (13/270) of the misoprostol group and 7% (19/272) of the placebo group. Additional oxytocic therapy was required by 3.3% and 4.7%, respectively. No predominance of side effects, particularly shivering, was noted in the misoprostol group. CONCLUSIONS: Postpartum use of 400 microg rectal misoprostol was well tolerated and associated with a statistically nonsignificant trend toward less postpartum hemorrhage. The early active management of excessive bleeding with conventional oxytocic agents may have reduced the potential of the study to detect differences between the groups.

Administration, Rectal↗
PubMed1995

Effects of a D-Cys6/L-Cys6 interchange in nonselective and selective vasopressin and oxytocin antagonists.

We report the solid-phase synthesis of the D-Cys6 analogues of arginine-vasopressin (AVP), peptide 1, of the selective AVP vasopressor (V1a receptor) antagonist [1-(beta-mercapto-beta,beta-pentamethylenepropionic acid),2-O-methyltyrosine]arginine-vasopressin (d(CH2)5[Tyr(Me)2]-AVP, (A)), peptide 2, of the three nonselective antidiuretic/vasopressor (V2/V1a receptor) AVP antagonists d(CH2)5[Tyr(Et)2]VAVP (B), d(CH2)5[D-Tyr(Et)2]VAVP (C), and d(CH2)5[D-Phe2]VAVP (D) (where V = Val4), peptides 3-5, of the nonselective oxytocin (OT) antagonists d(CH2)5-[Tyr(Me)2]OVT (E) and d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH2(9)]OVT (F) (where OVT = ornithine-vasotocin), peptides 6 and 7, and of the selective OT antagonists desGly-NH2,d(CH2)5[Tyr(Me)2,Thr4]OVT (G) and d(CH2)5]D-Trp2,Thr4]OVT (H), peptides 8 and 9. We also present the repeat syntheses of the previously reported d(CH2)5[D-Trp2]AVT (peptide 10) and its D-Cys6 analogue (peptide 11) (where AVT = arginine-vasotocin). Peptides 1-11 were assayed for agonistic and antagonistic activities in in vivo V1a, V2, and oxytocic assays and in in vitro oxytocic assays without and with 0.5 mM Mg2+. With V2 and V1a agonistic potencies of 0.82 and 0.41 units/mg, [D-Cys6]AVP has retained less than 0.3% of the V2 and V1a potencies of AVP. It exhibits no oxytocic activity and is an in vitro OT antagonist. pA2 = 6.67 (no Mg2+); pA2 = 5.24 (0.5 mM Mg2+). By contrast, with one or two exceptions, a D-Cys6/L-Cys6 interchange in antagonists 2-9, although resulting in reductions of antagonistic potencies in all assays for virtually all peptides 2-9 relative to A-H, has been well tolerated. For peptides 2-5, the anti-V2 and anti-V1a pA2 values range from approximately 5.54 to 7.33 and from 7.19 to 8.06, respectively; the range of in vitro anti-OT pA2 values (no Mg2+) is 7.35-7.87; with 0.5 mM Mg2+, the range is 7.24-8.21. Peptides 2 and 4 have in vivo anti-OT pA2s = 6.60 and 7.16, respectively. For peptides 6-9, the range of in vitro anti-OT pA2 values (no Mg2+) is 7.65-7.96; with 0.5 mM Mg2+, the range is 7.41-7.65, and the in vivo anti-OT pA2 values range from 6.85 to 7.33. With an in vivo anti-OT pA2 = 7.33, peptide 6 is equipotent with its parent E. The in vivo anti-OT potencies of peptides 7-9 are significantly reduced relative to those of F-H. The in vitro anti-OT (0.5 mM Mg2+) pA2 values of 10 and 11 are 7.54 and 7.50, both significantly lower than those previously reported.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1978

[1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid),4-valine,-8-D-arginine]vasopressin, a potent and selective inhibitor of the vasopressor response to arginine-vasopressin.

As part of a program in which we are attempting the design and synthesis of an antagonist of the antidiuretic response to arginine-vasopressin (AVP) [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid),4-valine,8-D-arginine]vasopressin [d(CH2)5VDAVP] was synthesized and assayed for antidiuretic, vasopressor, and oxytocic activities. The required protected intermediate was synthesized by a combination of solid-phase synthesis and an [8 + 1] coupling in solution. d(CH2)5VDAVP has an antidiuretic potency of 0.10 +/- 0.02 unit/mg, less than 1/10000 that of its parent [deamino,4-valine,8-D-arginine]vasopressin (dVDAVP). d(CH2)5VDAVP is a specific antagonist of the vasopressor responses to AVP. It has an antivasopressor pA2 value of 7.68 +/- 0.05 when tested against AVP. It is also an antagonist of the in vitro oxytocic response to oxytocin (pA2 value = 6.62 +/- 0.07). With its negligible antidiuretic activity, absence of oxytocic activity, and its potent and specific ability to antagonize the vasopressor effects of AVP, d(CH2)5VDAVP is one of the most potent and selective vasopressor antagonists reported to date. It should thus be a useful tool with which to probe the possible role(s) that AVP may play in cardiovascular regulation under normal and pathological conditions.

Animals↗
PubMed1983

Potent antagonists of the antidiuretic responses to arginine-vasopressin based on modifications of [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid),2-D- phenylalanine,4-valine]arginine-vasopressin at position 4.

As part of a program in which we are attempting (a) to delineate the structural features at positions 1-9 in our previously reported antidiuretic antagonists required for antidiuretic antagonism and (b) to obtain analogues with enhanced antiantidiuretic potency and/or selectivity, we have synthesized 14 new analogues of the antidiuretic antagonist [1-(beta-mercapto-beta,beta-cyclopentamethylenepropionic acid),2-D-phenylalanine,4-valine]arginine-vasopressin [d-(CH2)5-D-Phe2VAVP), in which the valine residue at position 4 was replaced by the following L-amino acids and glycine: Ile, Abu, Thr, Ala, Gln, Lys, Cha, Nle, Nva, Phe, Leu, Gly, Tyr, and Pro. These analogues are 1, d-(CH2)5-D-Phe2,Ile4AVP; 2, d(CH2)5-D-Phe2,Abu4AVP; 3, d(CH2)5-D-Phe2,Thr4AVP; 4, d(CH2)5-D-Phe2,Ala4AVP;5, d(CH2)5-D-Phe2AVP; 6, d(CH2)5-D-Phe2,Lys4AVP; 7, d(CH2)5-D-Phe2,Cha4AVP; 8, d(CH2)5-D-Phe2,Nle4AVP; 9, d(CH2)5-D-Phe2,Nva4AVP; 10, d(CH2)5-D-Phe2,Phe4AVP; 11, d(CH2)5-D-Phe2,Leu4AVP; 12, d(CH2)5-D-Phe2,Gly4AVP; 13, d(CH2)5-D-Phe2,Tyr4AVP; 14, d(CH2)5-D-Phe2,Pro4AVP. The protected intermediates required for the synthesis of all of these peptides were prepared by the solid-phase method and cleaved from the resin by ammonolysis. Following deblocking with Na in NH3 and oxidizing with K3[Fe(CN)6], each peptide was purified on Sephadex G-15 in a two-step procedure using 50% HOAc and 0.2 M HOAc as eluants. Analogues 1-14 were tested for agonistic and antagonistic activities by antidiuretic, vasopressor, and oxytocic assays in rats. Analogues 1, 2, and 4-6 exhibit no detectable antidiuretic agonistic activity. All analogues, with the exception of the Pro4-containing analogue, are antidiuretic antagonists. Their antiantidiuretic pA2 values are as follows: 1, 8.24 +/- 0.08; 2, 7.96 +/- 0.07; 3, 7.62 +/- 0.09; 4, 7.52 +/- 0.03; 5, 7.21 +/- 0.07; 6, 7.22 +/- 0.12; 7, 7.19 +/- 0.08; 8, 7.12 +/- 0.09; 9, 6.99 +/- 0.06; 10, 6.07 +/- 0.11; 11, 6.07 +/- 0.11; 12, 5.85 +/- 0.05; 13, approximately 5.57; 14, a weak agonist (0.004 U/mg). Analogues 1-14 also antagonize the vascular responses to arginine-vasopressin (AVP) and the in vitro oxytocic responses to oxytocin. Analogues 1, 2, 3, and 5 have also been shown to antagonize the in vivo oxytocic responses to oxytocin. Five of these analogues (1, 2, 3, 6, and 7) exhibit enhanced antiantidiuretic/antivasopressor selectivity. d(CH2)5-D-Phe2,Lys4AVP and other position-4 analogues with side-chain functional groups may be useful covalent ligands with which to probe the structural characteristics of AVP renal and vascular receptors. With an antiantidiuretic "effective dose" of 0.46 +/- 0.07 nmol/kg and a pA2 value of 8.24 +/- 0.08, d(CH2)5-D-Phe2,Ile4AVP (1) appears to be the most potent antidiuretic antagonist reported to date.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1968

The isolation of neurophysin-I and-II from bovine pituitary neurosecretory granules separated on a large scale from other subcellular organelles. Demonstration of slow equilibration of neurosecretory granules during centrifugation in a sucrose density gradient.

1. An improved procedure for the isolation of neurosecretory granules from the posterior lobe of the bovine pituitary gland is described. 2. Of the total oxytocic and pressor activities present in the original tissue 80% was sedimentable. 3. The granules were separated from mitochondria by prolonged centrifugation in a sucrose density gradient. During a sedimentation period of 5hr. the granules moved progressively into denser regions of the gradient and the mitochondria remained at the top. 4. The biological activities of the granules were measured: the oxytocic activity was 11.56+/-1.63 and the pressor activity was 15.60+/-3.91 units/mg. of protein. 5. A protein was isolated from a lysate of granules prepared from 40 pituitary glands. Amino acid analysis showed that it consisted of a mixture of neurophysin-I and neurophysin-II in equal proportions. It accounted for 60% of the soluble granule protein and for 50% of the total granule protein. 6. The neurophysins present in the granules are associated with 19.1 units of oxytocic and 21.1 units of pressor activity/mg. of protein. 7. Starch-gel electrophoresis revealed the presence of both neurophysins in extracts of 15 pituitary glands studied individually. 8. We conclude that the polypeptide hormones, oxytocin and [8-arginine]-vasopressin, are normally closely associated with the two neurophysins within neurosecretory granules of the pituitary gland.

Acid Phosphatase↗
PubMed1986

The effects of prostaglandin synthetase inhibitor indomethacin on the hypothalamic and neurohypophysial oxytocin content in euhydrated and dehydrated male white rats.

Rats euhydrated or dehydrated up to eight days were given intraperitoneally indomethacin (IM) twice daily in a dose of 0.2 mg/100 g of initial body weight. A single dose of IM injected to euhydrated animals did not affect the neurohypophysial oxytocic activity but decreased that potency in the hypothalamus. When IM was administered repeatedly during four or eight days, the hypothalamic oxytocic activity did not differ from the respective controls; under such conditions the oxytocic activity in the neurohypophysis increased progressively. Under conditions of dehydration the known depletion of hypothalamic and neurohypophysial oxytocin storage was not affected by indomethacin. It is therefore suggested that impulses of osmoreceptor origin are of distinct importance in determining the function of oxytocinergic neurones under conditions of inhibited prostaglandin synthesis.

Animals↗
PubMed1994

Special evolution of neurohypophysial hormones in cartilaginous fishes: asvatocin and phasvatocin, two oxytocin-like peptides isolated from the spotted dogfish (Scyliorhinus caniculus).

In contrast to most vertebrate species that possess one oxytocin-like hormone and one vasopressin-like hormone, a few groups, such as marsupials or cartilaginous fishes, are endowed with two peptides of either or both types, suggesting possible gene duplications. We have now isolated two oxytocin-like hormones from the pituitary of the spotted dogfish Scyliorhinus caniculus (suborder Galeoidei). Microsequencing as well as chromatographic and pharmacological comparisons with synthetic peptides show that these peptides are [Asn4,Val8]oxytocin (asvatocin) and [Phe3,Asn4,Val8]-oxytocin (phasvatocin). Asvatocin and phasvatocin display oxytocic activity on rat uterus, about 80 and 5 milliunits per nmol, respectively, and virtually no pressor activity on anesthetized rats. They occur in roughly equal molar amounts in the gland; vasotocin is also present in a proportional amount that is lower by about a factor of 20. In addition to the duality, conservative amino acid substitutions are observed in the two oxytocic peptides in positions 4 (Gln-4-->Asn) and 8 (Leu-8-->Val), when compared with oxytocin. Furthermore, replacement of the isoleucine residue found in position 3 of all other oxytocin-like hormones by phenylalanine in phasvatocin is exceptional; it determines a dramatic decrease of the oxytocic activity. Preservation of the C-terminal-amidated nonapeptide pattern in the 12 vertebrate neurohypophysial hormones known to date suggests that both precursors and processing enzymes have coevolved tightly. On the other hand, whereas the great evolutionary stability of the mature hormones (generally observed in vertebrates) suggests a strict messenger-receptor coevolution, the exceptional diversity found in cartilaginous fishes (six oxytocin-like peptides identified out of eight known) might be due to a looseness of selective constraints, perhaps in relationship with their specific urea osmoregulation.

Amino Acid Sequence↗
PubMed1975

Oxytocin analogs with substitutions in postions 3 and 4.

Synthesis and biological properties are reported for some analogs of oxytocin with replacements of the isoleucine residue in position 3, i.e., (3-proline)oxytocin and(3-D-alanine)oxytocin, and the glutamine residue in position 4, i.e., (4-D-alanine)-oxytocin and (4-D-leucin)oxytocin. (3-Proline)oxytocin exhibited smaller than0.02 U/MG oxytocic activity, 0.005 plus or minus smaller than 0.001 U/mg rat pressor activity and 0.003 plus or minus 0.0001 U/mg antidiuretic activity. (3-D-Alanine)oxytocin had no agonistic activity in the bioassays tested except for the rat antidiuretic assay (smaller than 0.0005 U/mg). The 4-D-alanine analog showed 0.05 plus or minus 0.003 U/mg oxytocic activity, 0.07 plus or minus 0.01 U/mg avian vasodepressor activity, and smaller than 0.001 U/mg rat antidiuretic activity. (4-D-Leucine)oxytocin possessed 0.001 plus or minus U/mg rat pressor activity, and showed slight inhibitory properties in the oxytocic and avian vasodepressor assays, inhibiting the oxytocin response in the latter assay by about 60% at a girnibe-to-analog ratio of 1:5000. The activity profiles of the analogs are compared to that of oxytocin and are discussed on the basis of the proposed solution conformation of oxytocin.

Alanine↗
PubMed1970

Water uptake by the crab-eating frog Rana cancrivora, as affected by osmotic gradients and by neurohypophysial hormones.

1. The rate of water uptake across the skin was investigated in live Rana cancrivora, an euryhaline frog which has been reported to tolerate sea water. When they were exposed to distilled water at 29 degrees C, the rate of water uptake was 8.4 +/- 0.4 mul./cm(2).hr; when bathed in solutions ranging from 30 to 570 m-osmole/l., irrespective of whether the solute was sucrose, urea or NaCl, the rate of fluid uptake during the first day was inversely related to the osmolarity of the solution. No appreciable fluid movement was observed when the bathing solution had an osmolar concentration of 270 m-osmole/l.2. The rate of fluid uptake was not affected by injections of vasopressin, oxytocin or of extracts of amphibian or rat pituitary glands, irrespective of whether R. cancrivora were bathed in distilled water or in solutions of NaCl or sucrose.3. In Bufo melanostictus, in contrast with R. cancrivora, injections of neurohypophysial extracts produced a marked increase of the rate of fluid uptake.4. In the laboratory, R. cancrivora could be acclimatized stepwise to tolerate NaCl solutions up to 700 m-osmole/l. for 7 days.5. After 24 hr exposure either to distilled water or to NaCl solutions from 100 to 670 m-osmole/l., the osmolar concentration of the plasma of R. cancrivora was always higher than that of the bathing fluid. In R. pipiens or R. temporaria plasma osmolar concentration was higher than that of the bathing fluid only when the latter did not exceed 300 m-osmole/l.6. Under all conditions investigated, the osmolar concentration of the urine of R. cancrivora was always lower than that of the plasma.7. The amounts of pressor and oxytocic activities of pituitary glands of R. cancrivora kept in distilled water or in NaCl solutions up to 300 m-osmole/l. were 8.9 +/- 0.8 and 1.8 +/- 0.3 m-u./gland, irrespective of sex or body weight within the range 30-50 g. After 3 days exposure to hypertonic NaCl solutions, the amounts of pressor and oxytocic activities were 14.7 +/- 1.2 and 3.1 +/- 0.3 m-u./gland. In both instances the pressor/oxytocic ratio was 4.9. Pituitary glands of R. temporaria similarly showed increased pressor and oxytocic activities after exposure to NaCl solutions of 300-360 m-osmole/l.

Animals↗
PubMed1981

Direct inhibition of testicular androgen biosynthesis by arginine-vasopressin: mediation through pressor-selective testicular recognition sites.

We have observed that arginine vasopressin (AVP) and related neurohypophysial hormones exert direct inhibition of testicular androgen biosynthesis in vitro. In this report, the functional identity of the putative testicular recognition sites mediating the antigonadal activity of the neurohypophysial hormones was investigated. Pressor-selective (but not antidiuretic- or oxytocic-selective) agonists of neurohypophysial hormones exerted a dose-dependent inhibition of the hCG-stimulated accumulation of testosterone by cultured rat testicular cells. In addition, potent pressor (but not oxytocic) antagonists brought about a dose-dependent blockage of the AVP-induced inhibition of testicular androgen biosynthesis. Thus, the antigonadal activity of neurohypophysial hormones is mediated by specific testicular recognition sites similar to those mediating the pressor actions of these neuropeptides but distinct from those involved in their antidiuretic or oxytocic effects.

Androgens↗
PubMed1991

[Serum oxytocin and oxytocinase activities in women during pregnancy].

Serum oxytocic and oxytocinase activities were examined in 50 females with normal pregnancy and 50 with threatened abortion by using biological (oxytocin) and biochemical (oxytocinase) methods. The findings suggest that there is no regular changes in serum oxytocic activity in the course of pregnancy, whereas its oxytocinase activity significantly increases with pregnancy development. The females with threatened abortion showed the same values of serum oxytocic activity as those with normal pregnancy, but much lower oxytocinase activity. The assay of serum oxytocinase activity may be of diagnostic value when threatened abortion is suspected.

Abortion, Threatened↗
PubMed1989

Kinins contribute to the contractile effects of rat glandular kallikrein on the isolated rat uterus.

Glandular kallikrein is known to promote contractions of the isolated, estrogenized rat uterus, perhaps independently of kinin formation. The recent availability of kinin receptor antagonists led us to study whether they might affect the oxytocic activity of kallikrein. DArg0-Hyp3-Thi5,8-DPhe7-bradykinin (8.5 x 10(-7) M) displaced the dose-response curves to both bradykinin (from 1.0 x 10(-9) to 4.0 x 10(-6) M) and kallikrein (from 4.7 x 10(-11) to 8.0 x 10(-9) M) approximately one order of magnitude to the right. This inhibition could not be due to a nonspecific effect on the uterine muscle, as the contractile response to oxytocin was not altered. In addition, carboxypeptidase B (a potent kininase) and kinin antibodies reduced the contractile response to kallikrein by 70 and 60%, respectively. Removal of the intervening agent restored the normal response. The effect of kallikrein depended on its enzymatic activity, inasmuch as kallikrein inactivated with D-Phe-Arg-Arg-CH2Cl was not oxytocic. Prolonged or multiple exposures to kallikrein completely abolished uterine response, whereas the effect of bradykinin was unaltered. Uterine horns rendered insensitive to kallikrein by prolonged exposure still contracted in response to trypsin. Kininogen was present in the uterine tissue in a concentration of 1.5 +/- 0.3 ng of bradykinin equivalents per mg wet wt. No more than 15.9 +/- 1.2% of this total was due to plasma contamination. Only 21.5 +/- 2.9% of total kininogen could be cleaved by kallikrein. We conclude that part of the oxytocic activity of kallikrein is related to generation of kinins from a kallikrein-sensitive kininogen present in the isolated rat uterus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

[Dynamic tests for monitoring fetal cardiac rhythm].

The oxytocic test was compared in 354 cases of "high risk" pregnancy with the simple recording of fetal heart rate. When the tracing of the simple recording was normal, the oxytocic test revealed a frankly pathological tracing in only 2.5 p. cent of cases. By contrast, if there were abnormal signs in the simple record, the oxytocic test was pathological in only 18.8 p. cent of cases. The test has only a relative value, as indicated by analyses of modes of labor and of the state of the child at birth.

Female↗
PubMedDate not supplied

[Assistance procedures in the perinatal period that condition breast feeding at the time of discharge from the hospital].

The authors have evaluated the influence of some obstetric events (type and duration of labour and method of delivery) and some pharmacological factors (oxytocic drugs during labour, local infiltration, duration of general anaesthesia, oxytocic drugs and/or ergot derivatives during puerperium) on frequency of breast-feeding at the time of discharge from hospital. About 57% of 356 newborns were breast-fed (wholly or prevalently) at discharge from the "A. Gemelli" University Hospital in Rome, during two months period (march-april 1981). The results showed that all those conditions requiring medical and paramedical action, either instrumental or pharmacological (such as: induced labour, prolonged labour, operative delivery either vaginal or abdominal, particularly in emergency; use of local infiltration; use of oxytocic drugs during labour, particularly for induction; prolonged general anaesthesia in caesarean section) may have an unfavorable effect, nearly always significant, on breast-feeding. According with these results, the Authors suggest the following measures for breast-feeding promotional programme: modification of neonatal routine care to promote an earlier mother-infant interaction during lying-in; limitation of avoidable obstetric procedures and of drugs giving to mothers; a better understanding of pharmacokinetics, both in mothers (placentar passage of drugs and through milk) and in newborns during labour, delivery and puerperium.

Anesthesia, Local↗
PubMedDate not supplied

Release of oxytocin from the rat posterior pituitary lobe incubated in situ and from the hypothalamic end of the cut pituitary stalk.

Release of oxytocin from the rat posterior pituitary lobe incubated in situ and from the hypothalamic end of the cut pituitary stalk. Acta Physiol. Pol., 1978, 29 (2):97--105. Using the method of incubation in situ of the posterior pituitary lobe and washing the hypothalamic end of the divided pituitary stalk the activity of neurosecretory neurons was investigated directly. The oxytocic activity of the fluid incubating in situ the posterior pituitary lobe or washing the hypothalamic end of the cut pituitary stalk was determined on the rat myometrium. The oxytocic activity disappeared from this fluid after inactivation with sodium thioglycolate. The samples of the fluid incubating the posterior pituitary lobe obtained at 30 min intervals showed alternatingly increased or decreased oxytocic activity. In the fluid washing the cut pituitary stalk the activity was highest from 31 to 60 minutes after division of the stalk.

Animals↗
PubMed1999

[Electrocardiographic changes during at term labor].

BACKGROUND: Electrocardiographic ST-changes are known to occur during pregnancy, puerperium and cesarean section or spontaneous labor under oxytocic, tocolytic and anesthetic treatment. The aim of the study was to detect ST-changes during spontaneous labor in healthy women, without anesthetic or oxytocic therapy, and to verify their relation to plasmatic electrolyte variations and other pathophysiologic factors. METHODS: Electrocardiograms were performed in 46 healthy women (age 30.4 +/- 6) at term pregnancy, during labor, 12-24 hours after delivery and then again three months after delivery. Hemochrome and sideremia were tested before labor and electrolytes (Na, K, Cl, Mg, Ca) were tested during each electrocardiogram. The patients were divided in two groups, patients with (group A) and without (group B) ST-changes. RESULTS: Before labor, three patients (7%) were in group A with nonspecific ST-changes (flat ST and/or fluctuating T wave) in precordial leads V2-V3-V4; group B had 43 patients (93%). During labor, group A included 27 patients (59%): 16 (59%) showed T inversion, 23 (85%) nonspecific changes, and eight (30%) had ST shift < or = 0.5 mm, in precordial and inferior leads. The three patients in group A before labor showed increased changes during labor. Group B had 19 patients (41%). Heart rate and blood pressure were within normal range in all patients. Early after delivery, seven patients out of 27 in labor were still in group A (15% of total) with nonspecific ST-changes; group B had 39 patients (85%). Three months after delivery, all patients were in group B. A drop in plasmatic K, detected during labor in all patients and returning to normal soon after delivery, was higher in group A than in group B (p < 0.01). CONCLUSIONS: ST-changes detectable during labor, similar to the ones described during pregnancy and puerperium but greater and more frequent, are independent of anesthetic and/or oxytocic treatment; they are not ischemic and disappear after delivery. They are related to the drop in plasmatic K, hyperventilation, hormonal changes, uterine contractions, O2-consumption and pain.

Adult↗