Stimulation of gastric secretion by prostaglandin F2 α in rats

Summary In rats with chronic gastric fistulas, prostaglandin F₂ stimulated the gastric acid secretion in graded doses of 50. 100, 200 and 400 g/kg b. wt, while higher doses above 1 mg/kg b. wt tended to inhibit significantly. The gastric antisecretory effect of prostaglandin E₁ could not be altered or modified by subsequent treatment of prostaglandin F₂ , while the latter alone without any prior treatment of the former, stimulated output of gastric juice, HCl and pepsin without significantly affecting the concentration of these components.Acknowledgement. The gift of the prostaglandin E₁ and prostaglandin F₂ is acknowledged to Dr J.E. Pike, Upjohn, USA. This paper was read at the IXth Annual Conference of the Indian Pharmacological Society held at Benares (1976) and abstracted in the Indian J. Pharmac.9, 73 (1977).     

Age-related differences in the urinary excretion of prostaglandin F2α catabolites in the rat

Summary Tritium-labelled PGF₂ was administered i.v. into rats of varying ages (2, 4, 6 weeks and adult). Urine was collected and assayed for radioactive products by thin-layer-chromatography. Results showed a distinctly different urinary profile between the 2-week-old and the adult rat. While the urinary pattern from the 2-week-old rat gave a single less polar product than PGF₂, the pattern from the adult rat gave products more polar than PGF₂. Urine from the 4- and 6-week-old rats gave a mixture of these types of products. These results indicate that some prostaglandin catabolic pathway (likely the -oxidative system) is activated in vivo within the 4–6-week postnatal period in the rat.Supported by a grant (MT-4181) to C.P.-A. from the Medical Research Council of Canada.This study is in partial fulfillment of the requirements for a Ph.D. degree in the Department of Pharmacology, University of Toronto.     

The microbiological dehydrogenation of 16β-methyl-5α-dehydrocortisone

Zusammenfassung Über die mikrobiologische Umwandlung des 16-Methyl-5-Dehydrocortisons in 16-Methylprednison durch einen Stamm vonCorynebacterium simplex wird berichtet. Mit Hilfe dieser Bakterienkulturen ist es möglich, in relativ kurzer Zeit die beiden Doppelbindungen in den Stellungen 1 und 4 im A-Ring des 16-Methylprednisons einzuführen.     

Sur l'inversion de l'action hypertensive de la prostaglandine F2α, chez le rat

Summary In normal rats, prostaglandin F₂ is a potent vasoconstrictor. The corresponding systemic hypertension is progressively attenuated by tachyphylaxis, revealing a longlasting fall of blood pressure. Tachyphylaxis is accelerated by previous injection of arachidonic acid and bradykinin. The vasodepressive activity of PGF₂ is inhibited by indomethacin.

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Nous remercions vivement le docteurPike (Upjohn, Kalamazoo) qui nous a fourni gracieusement ces prostaglandines.     

Activation ofα-carbons of amides

Summary The reactions of Vilsmeir complexes of amides/imides with electrophiles afford the corresponding -substituted products in good yield.     

Inhibition ofα-chymotrypsin by 2-halogeno-ethanols; comparison with 2-methyl-ethanols and urea

Summary 2-Halogeno- and 2-methyl-ethanols inhibit-chymotrypsin in the order of their substituted groups: [1] tri>di->mono-, [2] Br->Cl->CH₃->F-. The inhibition by the halogeno-ethanols is mediated differently from that by the methyl-ethanols, ethanol, and urea.     

Preliminary note on certain pharmacological properties of 3β, 16α-dihydroxyallopregnan-20-one

Zusammenfassung 3, 16- Dihydroxyallopregnan-20-one hat die Eigenschaft, bei der Mehrzahl adrenopriver, salzbelasteter Ratten im Harn eine Natrium-Mehrausscheidung hervorzurufen.     

C16-methyl derivatives of progesterone and 17α-acetoxyprogesterone: Preparation and biological activities

Zusammenfassung Mehrere Derivate des 16-Methyl-progesteron wurden synthetisiert und biologisch geprüft. Die Einführung einer C16-Methylgruppe ergab keine gesteigerte Progesteronaktivität in den getesteten Verbindungen.     

Morphological effects of prostaglandins E1, E2 and F2α on fibroblast-like cultures of human synovial cells

Summary In medium supplemented with serum, PGE₁ and PGE₂ were equally potent in inducing cells with a fenestrated appearance, whereas PGF₂ was comparatively ineffective. In BSA without serum the effects were more persistent and characterized by a high proportion of astrocyte-like cells. The effects were reversed upon removal of the prostaglandins.This work was supported by the National Health and Medical Research Council of Australia.     

Effects on prostaglandins F2α, I2, and indomethacin on isolated coronary arteries from healthy and alloxandiabetic dogs

Summary Contractile responses of isolated coronary arteries from healthy and alloxan-diabetic dogs to prostaglandin F₂ were enhanced by indomethacin and inhibited by prostaglandin I₂. The potentiation by indomethacin was more prominent in diabetic vessels than in normal arteries.     

A new prostaglandin metabolite of arachidonic acid. Formation of 6-keto-PGF1α by the rat stomach

Summary Arachidonic acid was transformed by rat stomach homogenates into a new prostaglandin viz. 6-Keto-PGF₁. Its structure was confirmed by mass spectrometry.Supported by a grant No. MA-4181 from the Medical Research Council of Canada. All mass spectra were recorded by Mr.L. Marai on the Varian MAT CH-5 gas chromatograph-mass spectrometer at the Best Institute, Toronto, an MRC regional facility.     

Hydrolysis of N-phenylacetyl-α-methyl-α-amino acids by benzylpenicillinacylase

Summary Enzymatic hydrolysis of several racemic N-phenylacetyl--methyl--amino acids containing an additinal aliphatic, aromatic or polar substitutent on the chiral carbon atom, has been studied by using benzylpenicillincylase fromEscherichia coli A.T.C.C. 9637. Both the rate of hydrolysis and the stereoselectivity were found to be considerably lower than in the case of natural -amino acids. Steric and electronic factors in the side chains influencing the stereoselectivity are discussed.     

Scattering ofα-particles from nuclei

Zusammenfassung Nach einem Überblick über dieRutherfordsche Theorie der Ablenkung von -Teilchen im elektrostatischen Feld des Atomkernes wird auf kürzliche Streuexperimente hingewiesen. Die Streuung von -Teilchen an schweren Kernen ist einem optischen Beugungsphänomen ähnlich. Resonanzen wie sie in der Streuung an leichten Kernen beobachtet werden, sind akustischen Resonanzen vergleichbar.     

Extrahepatic 7α-hydroxylation of dehydroepiandrosterone

Zusammenfassung In verschiedenen Rattenorganen (Lunge, Niere, Milz, Blut, Muskelgewebe) konnte ein System nachgewiesen werden, das imstande ist,in vitro Dehydroepiandrosteron an der 7-Stellung zu hydroxylieren. Dies Ergebnis weist auf die allgemein mögliche extrahepatale und extraadrenale Steroidhydroxylation hin.     

Age distribution of circulatingα-interferon

Summary A sensitive radioimmunoassay showed that circulating -interferon in the plasma of healthy individuals was low in children and reached the highest level in the young adult, then declined gradually with age. Circulating -interferon was 0.201±0.059 ng/ml in males (n=19) and 0.184±0.076 ng/ml in females (n=14) at ages 30–39 years old. It was noted that circulating -interferon was maintained up to a certain level even in elderly individuals.     

Preferences of transmembrane helices for cooperative amplification of Gαs and Gαq signaling of the thyrotropin receptor

The majority of constitutively activating mutations (CAMs) of the thyroid-stimulating hormone receptor display a partially activated receptor. Thus, full receptor activation requires a multiplex activation process. To define impacts of different transmembrane helices (TMHs) on cooperative signal transduction, we combined single CAMs in particular TMHs to double mutations and measured second messenger accumulation of the G_αs and the G_αq pathway. We observed a synergistic increase for basal activity of the G_αs pathway, for all characterized double mutants except for two combinations. Each double mutation, containing CAMs in TMH2, 6 and 7 showed the highest constitutive activities, suggesting that these helices contribute most to G_αs-mediated signaling. No single CAM revealed constitutive activity for the G_αq pathway. The double mutations with CAMs from TMH1, 2, 3 and 6 also exhibited increase for basal G_αq signaling. Our results suggest that TMH2, 6, 7 show selective preferences towards G_αs signaling, and TMH1, 2, 3, 6 for G_αq signaling.     

An immunohistochemical and ultrastructural comparison of the effects of 2-bromo-α-ergocryptine on intrasellar and transplanted rat pituitaries

Summary Following 2 weeks of administration of 2-bromo--ergocryptine, a marked decrease was observed in prolactin immunoreactivity of the grafted pituitaries, whereas no reduction was noted in the intrasellar pituitaries. No evidence of crinophagy was revealed by electron microscopy in prolactin cells of 2-bromo--ergocryptine-treated rats.Acknowledgments. This work was supported in part by the Medical Research Council of Canada (grant MA-6349). The excellent technical assistance of Mrs Cynthia Edwards and secretarial help of Mrs Wanda Wlodarski are gratefully acknowledged.     

Conversion of 17α-hydroxypregnenolone to cortisol

Zusammenfassung Nebennierenschnitte von Ratten, Meerschweinchen und Menschen synthetisierten 17-Hydroxyprogesteron, 11-Deoxycortisol und Cortisol aus 17-Hydroxypregnenolon. Diese Verbindung, als Ausgangsprodukt für die Cortisolsynthese, ist ebenso wirksam wie pregnenolon. Die Umwandlung von 17-Hydroxypregnenolon in Dehydroepiandrosteron verläuft weniger vollkommen als zu 17-Hydroxycorticoiden.