Gametes contain angiotensin converting enzyme (kininase II)

The localization of angiotensin converting enzyme (ACE) in the gonads of the normal rabbit was studied by immunofluorescence and immunoelectron microscopy. The enzyme is present in the cytoplasm of testicular spermatids and of epididymal and ejaculated spermatozoa, and on the surface of follicular and tubal oocytes. These findings support the hypothesis that ACE has a role in gamete maturation and in fertilization.     

Gametes contain angiotensin converting enzyme (kininase II)

Summary The localization of angiotensin converting enzyme (ACE) in the gonads of the normal rabbit was studied by immunofluorescence and immunoelectron microscopy. The enzyme is present in the cytoplasm of testicular spermatids and of epididymal and ejaculated spermatozoa, and on the surface of follicular and tubal cocytes. These findings support the hypothesis that ACE has a role in gamete maturation and in fertilization.Acknowledgments. This study was supported by NIH grant AM36807 and by grants from the American Heart Association, the Joe and Emily Lowe Foundation, and the Dana Foundation. We thank L. Fernandez, B. Luders, I. Pawlowski, and K. Schwegler for technical assistance.     

Studies on the hydrolysis of bradykinin by angiotensin-converting enzyme (kininase II)

Summary Arg-Pro-Pro-Gly-Phe, the N-terminal pentapeptide of bradykinin, is not an inhibitor of angiotensin-converting enzyme and is not hydrolyzed by the enzyme. Arg-Pro-Pro, the N-terminal tripeptide is a relatively potent (IC₅₀=2.3×10⁶ M) inhibitor but its higher homolog, Gly-Arg-Met-Lys-Arg-Pro-Pro is not an inhibitor of angiotensin-converting enzyme.This work was supported in part by grants from the US Public Health Service (HL 18415, HL 15691, HL 19764) and the John A. Hartford Foundation, Inc., and by the Medical Research Service of the Veterans Administration.     

Potentiation of bradykinin and eledoisin by BPF (bradykinin potentiating factor) fromBothrops jararaca venom

Zusammenfassung Nachweis der pharmakologischen Wirkung des Bradykinins am isolierten Meerschweinchenileum und am deutlichen Blutdruckanstieg bei Hund und Katze nach Vorbehandlung mit BPF (Bradykinin-potenzierender Faktor aus Jararcagift). Unter diesen Bedingungen werden mit Bradykinin gleich intensive Effekte wie mit Eldoisin erhalten.

---

---

This work was aided by research grants from the Fundação de Amparo à Pesquisa and from the Public Health Service, National Institute of Health, Bethesda (Md. USA) (NB. 02953-03).     

Synthesis of bradykinin potentiating pentapeptide (BPP5a)

Summary This synthesis is especially suitable for production of highly-purified bradykinin-potentiating pentapeptide (BPP_5a) because of the high yields of the coupling and deprotection reactions, accompanied by minimal side reactions, and the need for only one simple final purification step.The authors wish to thankJ. Pallak for carrying out the aminoacid analyses and bio-assays.     

Potentiation of the cerebral vascular action of bradykinin by the ‘bradykinin potentiating factor’ (BPF) in the dog

Zusammenfassung Die gefässerweiternde Wirkung von Bradykinin und Kallidin auf den cerebralen Kreislauf wurde durch den «BPF»-Faktor aus Schlangengift erheblich potenziert, während sie bei Eledoisin und Histamin nur wenig verändert wurde.     

Activity of a dipeptidyl carboxypeptidase (angiotensin converting enzyme) in lungs of different animal species

Résumé On a dosé la dipeptidyl-carboxypeptidase (responsable de la conversion de l'angiotensine I en angiotensine II) dans des préparations de poumons de 10 espèces différentes. Les espèces se classent comme suit par ordre décroissant de teneur en enzyme: rat > lapin, souris > cheval, chien, porc, mouton > buf, cobaye > veau, homme. Chez la plupart des espèces, l'enzyme est fixé a une structure subcellulaire sédimentable.     

Angiotensin I converting enzyme activity in pulmonary tissue of fetal and newborn rabbits

Summary Angiotensin I converting enzyme in pulmonary tissue of fetal and newborn rabbits was measured using Hip-His-Leu as substrate. Enzyme activity was detected in the late fetal period, increased gradually until birth and increased markedly after birth. Enzyme activity reached adult levels on the 2nd and 3rd day after birth. This observations suggests that the metabolic activity of the lung for angiotensin develops suddenly at the time of derivery.This work was supported in part by grant No. 187032 from Ministry of Education.     

Potentiation by crude kallikrein of the myotropic effect of angiotensin I in the isolated rabbit aortic strip

Summary Crude kallikrein (Padutin^®), but not pure kallikrein, when preincubated with angiotensin I caused a potentiation of the myotropic effect of decapeptide on the isolated continuously superfused rabbit aortic strip. Addition of converting enzyme inhibitor, SQ 20881, to the medium inhibited this potentiation. The potentiation by crude kallikrein of the myotropic effect of angiotensin I is probably due to the conversion of decapeptide to octapeptide angiotensin II. This study indicates that Padutin is not a pure kallikrein preparation and probably contains a kininase fraction which causes the conversion of angiotensin I.The authors are greatful to Prof. G. L. Haberland, Bayer AG, Elberfeld (BRD), for his generous gift of pure Kallikrein^® KZC 1/75; to Bayer, Leverkusen (BRD), for Padutin^® and to Squibb, New Jersey, USA, for SQ 20881. This work is supported in part by Eczacibai Research Foundation, Levent, Istanbul, Turkey. The technical assistance of Mr. M. Kabaçam is greatly appreciated.     

Potentiation by crude kallikrein of the myotropic effect of angiotensin I in the isolated rabbit aortic strip.

Crude kallikrein (Padutin), but not pure kallikrein, when preincubated with angiotensin I caused a potentiation of the myotropic effect of decapeptide on the isolated continuously superfused rabbit aortic strip. Addition of converting enzyme inhibitor, SQ 20881, to the medium inhibited this potentiation. The potentiation by crude kallikrein of the myotropic effect of angiotensin I is probably due to the conversion of decapeptide to octapeptide angiotensin II. This study indicates that Padutin is not a pure kallikrein preparation and probably contains a kininase fraction which causes the conversion of angiotensin I.     

Profound hypothermia in golden hamsters (Mesocricetus auratus) induced by serotonergic potentiating and noradrenergic inhibiting drugs

Profound hypothermia (6 degrees C) was induced in cold exposed golden hamsters (Mesocricetus auratus) by a combination of drugs that potentiate brain serotonergic activity (fluoxetine and pargyline) and inhibit noradrenergic activity (alpha-methyl-p-tyrosine). Individual drugs and combinations of 2 were ineffective.     

Profound hypothermia in golden hamsters (Mesocricetus auratus) induced by serotonergic potentiating and noradrenergic inhibiting drugs

Summary Profound hypothermia (6°C) was induced in cold exposed golden hamsters (Mesocricetus auratus) by a combination of drugs that potentiate brain serotonergic activity (fluoxetine and pargyline) and inhibit noradrenergic activity (alpha-methyl-p-tyrosine). Individual drugs and combinations of 2 were ineffective.Acknowledgements. We acknowledge the support of a research grant PCM74-05158 A01 to A.H.M. from the National Science Foundation (USA) and thank Lilly Research Laboratories, Indianapolis, Indiana, for the gift of fluoxetine (Lilly 110140).     

Chemotaxis of rabbit macrophages in vitro: Inhibition by drugs

Summary Chemotaxis of rabbit macrophages was inhibited in vitro by phenylbutazone and sodium salicylate, but not by other antiinflammatory agents. Other inhibitory compounds were colchicine, vincristine, PHA, Con A, iodoacetic acid, cytochalasin B, and EDTA. Some of these in vitro results contrast apparently with in vivo effects.     

The inhibition of cathepsin B by plasma haptoglobin biochemistry (enzymes,metabolism)

Summary Purified haptoglobin partially inhibits the activity of a lysosomal thiol proteinase, cathepsin B. This inhibition is reversible in the presence of monospecific antiserum to haptoglobin.This work was supported by an East Anglian Regional Health Authority Grant.