Degradation of oxytocin by the human placenta: effect of selective inhibitors.

  title={Degradation of oxytocin by the human placenta: effect of selective inhibitors.},
  author={S. Mizutani and H. Yokosawa and Y. Tomoda},
  journal={Acta endocrinologica},
  volume={127 1},
The hydrolysis of oxytocin by human placental subcellular fractions was studied in the presence of selective inhibitors by measuring liberated amino acids by high performance liquid chromatography (HPLC). Oxytocin degradation by microsomal and lysosomal fractions was inhibited by bestatin, amastatin and puromycin. The IC50 values of these inhibitors on oxytocin degradation by both fractions were similar to those of these inhibitors on the human placental aminopeptidase M measured by L-Leu-p… Expand
6 Citations
Initiating and responsible enzyme of arginine vasopressin degradation in human placenta and pregnancy serum
The immunotitration study clearly showed that the initiating and responsible protease in AVP degradation in human placenta and pregnancy serum is P-LAP. Expand
Oxytocin is hydrolyzed by an enzyme in human placenta that is identical to the oxytocinase of pregnancy serum
The immunotitration study and the effect of bastatin on the oxytocin-degrading protease showed that the initiating and responsible protease in oxyotocin degradation in human placenta and pregnant serum is P-LAP. Expand
Immunoaffinity purification and characterization of native placental leucine aminopeptidase/oxytocinase from human placenta.
cDNA cloning of placental leucine aminopeptidase (P-LAP)/cystinyl aminopeptidase (CAP)/oxytocinase demonstrated that this enzyme is a type II integral membrane protein, which means that native P-LAP,Expand
On the role of prolyl oligopeptidase in health and disease
The relevance of the peptidase in the metabolism of various neuropeptides is evaluated and the recognition of novel forms and relatives of POP may improve the understanding of how this family of proteins functions in normal and in neuropathological conditions. Expand
The oxytocin system in drug discovery for autism: Animal models and novel therapeutic strategies
How animal models have been utilized to understand the role of OT in social cognition and how those findings can be applied to the conceptualization and treatment of the social impairments in ASD are discussed. Expand
Placental metabolism and its regulation in health and diabetes.


Plasma oxytocinase: the synthesis and biological properties of the first product of the degradation of oxytocin by this enzyme.
Results suggest that there are molecular features of oxytocin other than its N-terminal residue that facilitate its interaction with plasma Oxytocinase, and this peptide is shown to be of very low potency in milk-ejection-Bike activity and uterotonic activity. Expand
In vitro degradation of oxytocin by pregnancy serum, placental subcellular fractions and purified placental aminopeptidases.
The degradation of oxytocin by human placental particulate and soluble fractions, pregnant and non-pregnant sera, and purified enzymes, and the combination of the post-proline endopeptidase with porcine kidney LAP or with placental microsomal P-LAP actively liberated all amino acids and amides detectable by HPLC. Expand
Mechanism of inactivation of oxytocin by rat kidney enzymes.
Kidney homogenate showed the highest degree of inactivating activity, and essentially all the enzymic activity was recovered in the centrifugal supernatant; this finding supports the contention that the kidney is the major organ involved in the inactivation of oxytocin. Expand
In vitro degradation of angiotensin II (A-II) by human placental subcellular fractions, pregnancy sera and purified placental aminopeptidases.
It was concluded that P-LAP (microsomal) together with aminopeptidase A seem to contribute greatly to the degradation of A-II in pregnant women. Expand
Differences in the enzymatic inactivation of arginine vasopressin and oxytocin by rat kidney homogenate.
The data are interpreted to indicate that the difference in the overall mechanism of inactivation of the two hormones by the rat kidney extract is a result of the high level of the enzymic activity which releases Gly-NH2 directly from oxytocin, compared to the low level of activity released from the antidiuretic hormone. Expand
Metabolism of neuropeptides. Hydrolysis of the angiotensins, bradykinin, substance P and oxytocin by pig kidney microvillar membranes.
Results show that a range of neuropeptides are efficiently degraded by microvillar membranes and that endopeptidase-24.11 plays a key role in this process. Expand
The distribution of enzymes destroying oxytocin and vasopressin in human placentae
The nature of the destruction of oxytocin and vasopressin by homogenate of human placentae is established and whether or not there were present inplacentae two separate systems each selectively destroying these posterior pituitary hormones is shown. Expand
Identification of human placental leucine aminopeptidase as oxytocinase.
The results suggest that P-LAP shows oxytocinase activity and plays an important role in the regulation of the plasma level of these hormones during pregnancy. Expand
Purification and properties of a bovine brain thyrotropin-releasing-factor deamidase. A post-proline cleaving enzyme of limited specificity.
  • S. Tate
  • Medicine
  • European journal of biochemistry
  • 1981
A bovine brain thyrotropin-releasing-factor (thyroliberin) deamidase has been purified 1100-fold to apparent homogeneity. Molecular weight estimates by gel filtration and sodium dodecylsulfate gelExpand
Purification and characterization of human placental aminopeptidase A.
Human placental aminopeptidase A was markedly activated by alkaline earth metals (Ca2+, Sr2+, Ba2+), but strongly inhibited by metal chelating agents such as EDTA and o-phenanthroline. Expand