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

The author studied the uterine reactivity of alloxan-diabetic rats to oxytocin. Using the Magnus method with Ringer-Locke nutrient solution (modified by Garcia de Jalon) low in calcium and varying the bath temperature from 30 degrees C to 36 degrees C, modifications of the organ were observed. The dose-effect relationship was only practicable in uterus of normal rats at 30 degrees C. When the bath temperature reached 35 degrees C, it was only possible to evaluate the uterine reactivity of alloxan rats by fixed periods of rhythmical contractions, that were graphically represented. This modification in the experiment resulted from the absence of reactivity of the alloxanic rat organ at 30 degrees C. Besides describing the methodology applied, the author suggests a hypothesis about the role of Ca++ on the variation of uterine reactivity. A previous administration of diethylstilbestrol (estrogenic hormone) in alloxanic rats, not treated with insulin, was followed by recovery of uterine reactivity, reinforcing the hypothesis of the mobilization of Ca++ in discompensated alloxan-diabetic rats as a factor of variations on the sensibility of the tissues.
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PMID:[Uterine reactivity of alloxan-diabetic rats to oxytocin (author's transl)]. 56 68

Freshly obtained human placentas from various periods of gestation were quantitatively analysed for their immunoreactive oxytocin (OT) content and its biological activity was examined in a Magnus apparatus by utilizing rat uterus. The mean values for placental immunoreactive OT per gram tissue increased from the first to the second trimester, maintaining its high level to term. The total content of placental OT also increased continually from the beginning of pregnancy to term. Blood levels of estrogen stimulated neurophysin (ESN) and OT were concomitantly enhanced through gestation. Placental extract and synthetic OT showed similar peaks in the elution pattern of ion-exchange chromatography through a carboxymethyl cellulose column. Synthetic OT and placental extract induced marked uterine contraction in diestrous rats. However placental extract previously incubated with OT antiserum failed to induce this effect. Though detection of immunoreactive OT by immunoassay alone does not provide definite identification of pituitary and placental OT, the present study suggests that placental immunoreactive OT could have a contracting effect on the uterine muscle.
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PMID:Detection of immunoreactive human placental oxytocin and its contractile effect on the uterine muscle. 666 73

The physiological roles of oxytocin in pregnant rats were studied by passive immunization. Oxytocin antibody (A/S OT) was produced to synthetic OT in rabbits by immunizing with OT conjugated to bovine serum albumin by glutaraldehyde method. Then the sera in the rabbits were tested for the potency of antibody to OT by double antibody radioimmunoassay. On the nineteenth day of pregnancy, each of ten rats was daily injected subcutaneously with 1 ml of A/S OT up to parturition. The mean gestation period in the treated rats was 23.1 +/- 0.31 days and in the control rats (normal rabbit serum: NRS treated), 23.2 +/- 0.13 days. The amount, 1 ml of antiserum, was inferred to be capable to sufficiently neutralize the endogenous oxytocin in pregnant rats. This antiserum was proved to inhibit the biological action of OT by Magnus equipment. These data suggest that, the hypothesis that OT may play a primary role of initiation of labor, is necessary to be reevaluated.
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PMID:[Study on passive immunization for biological action of oxytocin (author's transl)]. 724 66

A cDNA clone coding for an oxytocin-like substance was prepared from a human placental cDNA library using oxytocin antiserum. The cDNA size was approximately 900 bp. A mammalian expression vector containing the cDNA was constructed and transfected into Chinese hamster ovary (CHO) cells. The expression of immunoreactivity to oxytocin antiserum was observed by radioimmunoassay. The cultured medium of the transfected cells was assayed for uterine muscle contractile bioactivity using a Magnus apparatus. Bioactivity was eliminated by incubation with oxytocin antiserum. Thus, the cDNA clone, screened with oxytocin antibody, is surmised to code for an oxytocin-like activity, but the nucleotide and amino acid sequences responsible for the biological activity remain to be clarified.
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PMID:A uterine muscle contractile substance obtained from a human placental cDNA library. 821 30