METABOLISM OF 17α-HYDROXYPROGESTERONE-4-14C-17α-CAPROATE BY HOMOGENATES OF RAT LIVER AND HUMAN PLACENTA

1961 ◽  
Vol 36 (4) ◽  
pp. 511-519 ◽  
Author(s):  
Margaret Wiener ◽  
Charles I. Lupa ◽  
E. Jürgen Plotz
Keyword(s):  
Rat Liver ◽  
Human Placenta ◽  
Steric Hindrance ◽  
Placental Tissue ◽  
Caproic Acid ◽  
Major Product ◽  
Side Chain ◽  
Anaerobic Conditions ◽  
Prolonged Action ◽  
Long Acting

ABSTRACT 17α-hydroxyprogesterone-4-14C-17α-caproate (HPC), a long-acting progestational agent, was incubated with homogenates of rat liver and human placenta. The rat liver was found to reduce Ring A of HPC under anaerobic conditions to form allopregnane-3β,17α-diol-20-one-17α-caproate and pregnane-3β,17α-diol-20-one-17α-caproate, the allopregnane isomer being the major product. The caproic acid ester was neither removed nor altered during the incubation. Placental tissue did not attack HPC under conditions where the 20-ketone of progesterone was reduced. It is postulated that this absence of attack on the side chain is due to steric hindrance from the caproate ester, and that this may account for the prolonged action of HPC.

scholarly journals Accumulation of amino acids by the perfused rat liver in the presence of ethanol

1973 ◽  
Vol 134 (3) ◽  
pp. 697-705 ◽  
Author(s):  
Hans A. Krebs ◽  
Reginald Hems ◽  
Patricia Lund
Keyword(s):  
Amino Acids ◽  
Rat Liver ◽  
Major Effect ◽  
Major Product ◽  
Control Mechanisms ◽  
Perfused Rat Liver ◽  
Carbamoyl Phosphate ◽  
Lactate Formation ◽  
Gluconeogenesis From Alanine ◽  
Almost All

1. The rate of gluconeogenesis from alanine in the perfused rat liver is affected by the presence of other metabolizable substances, especially fatty acids, ornithine and ethanol. Gluconeogenesis is accelerated by oleate and by ornithine. When both oleate and ornithine were present the acceleration was greater than expected on the basis of mere additive effects. 2. Much NH3 and some urea were formed from alanine when no ornithine was added. With ornithine almost all the nitrogen released from alanine appeared as urea. 3. Lactate was a major product of alanine metabolism. Addition of oleate, and especially of oleate plus ornithine, decreased lactate formation. 4. Ethanol had no major effect on gluconeogenesis from alanine when this was the sole added precursor. Gluconeogenesis was strongly inhibited (87%) when oleate was also added, but ethanol greatly accelerated gluconeogenesis when ornithine was added together with alanine. 5. In the absence of ethanol the alanine carbon and alanine nitrogen removed were essentially recovered in the form of glucose, lactate, pyruvate, NH3 and urea. 6. In the presence of ethanol the balance of both alanine carbon and alanine nitrogen showed substantial deficits. These deficits were largely accounted for by the formation of aspartate and glutamine, the formation of which was increased two- to three-fold. 7. When alanine was replaced by lactate plus NH4Cl, ethanol also caused a major accumulation of amino acids, especially of aspartate and alanine. 8. Earlier apparently discrepant results on the effects of ethanol on gluconeogenesis from alanine are explained by the fact that under well defined conditions ethanol can inhibit, or accelerate, or be without major effect on the rate of gluconeogenesis. 9. It is pointed out that in the synthesis of urea through the ornithine cycle half of the nitrogen must be supplied in the form of asparate and half in the form of carbamoyl phosphate. The accumulation of aspartate and other amino acids suggests that ethanol interferes with the control mechanisms which regulate the stoicheiometric formation of aspartate and carbamoyl phosphate.

Labour-associated changes in adrenomedullin content in human placenta and fetal membranes

2003 ◽  
Vol 105 (4) ◽  
pp. 419-423 ◽  
Author(s):  
A. AL-GHAFRA ◽  
N. M. GUDE ◽  
S. P. BRENNECKE ◽  
R. G. KING
Keyword(s):  
Human Placenta ◽  
Mode Of Delivery ◽  
Placental Tissue ◽  
Fetal Membrane ◽  
Fetal Membranes ◽  
Tissue Extracts ◽  
Human Labour ◽  
Labour Group

The aim of the present study was to determine the effects of labour and mode of delivery on human placental and fetal membrane content of adrenomedullin (AdM). Placentas and fetal membranes were collected either at term or pre-term gestation from women either in labour or not in labour, and AdM was measured in tissue extracts by specific RIA. There were significant increases in AdM concentrations in amnion and choriodecidua for the in-labour group compared with the not-in-labour group for both pre-term and term gestations. There was no difference in AdM concentration in placental tissue between labour groups. This study provides evidence that fetal membrane AdM is increased in amniotic and choriodecidual tissues in response to labour, and suggests that it may play a role during human labour.

Role of side-chain amidation for the anticholestatic action of nourursodeoxycholic acid in rat liver

2009 ◽  
pp. 163-165
Author(s):  
S. Maitz ◽  
G. U. Denk ◽  
R. Wimmer ◽  
C. Rust ◽  
P. Invernizzi ◽  
...  
Keyword(s):  
Rat Liver ◽  
Side Chain

The Rates and Products of Addition of 4-Chlorobenzenesulfenyl Chloride to a Series of Side Chain Methyl Substituted Styrenes

1974 ◽  
Vol 52 (9) ◽  
pp. 1807-1812 ◽  
Author(s):  
George H. Schmid ◽  
Dennis G. Garratt
Keyword(s):  
Steric Hindrance ◽  
Side Chain ◽  
Methyl Groups ◽  
Methyl Group

The rates of addition and the product compositions have been determined for the addition of 4-chlorobenzenesulfenyl chloride to a series of seven side chain methyl substituted styrenes in 1,1,2,2-tetrachloroethane at 25°. Unlike the addition to the corresponding series of methylated ethylenes, the effect of the methyl groups is not cumulative. The effect of the methyl groups depends upon whether or not the β-methyl group is cis to the phenyl. When it is cis, the rate of addition is decreased compared to styrene and substitution of additional methyl groups has only a small effect on the rate of addition. In compounds lacking a cis-β-methyl group the rate of addition more closely resembles that for addition to the methylated ethylenes. Steric hindrance between the cis-methyl and phenyl groups is believed to be the cause of this difference in behavior between the ethylene and styrene series.

INACTIVATION AND DEGRADATION OF PORCINE CALCITONIN BY RAT LIVER, AND RELATIVE STABILITY OF SALMON CALCITONIN

1970 ◽  
Vol 48 (2) ◽  
pp. 181-188 ◽  
Author(s):  
M. de LUISE ◽  
T. J. MARTIN ◽  
R. A. MELICK
Keyword(s):  
Biological Activity ◽  
Rat Liver ◽  
Salmon Calcitonin ◽  
Trichloroacetic Acid ◽  
Maximal Activity ◽  
Active Principle ◽  
Rat Tissues ◽  
Prolonged Action ◽  
High Potency ◽  
Dose Dependent

SUMMARY Slices and homogenates of a number of rat tissues inactivated porcine calcitonin labelled with 125I; the most active tissue was the liver. Maximal activity was found in rat liver supernatant. The reaction was pH- and dose-dependent, the active principle was non-diffusible, inhibited by p-chloromercuribenzoate and EDTA, and destroyed by heat. Biological activity of calcitonin was lost parallel with the breakdown of the labelled calcitonin (as measured by loss of trichloroacetic acid precipitability). Salmon ultimobranchial calcitonin was much less susceptible to inactivation by rat liver supernatant than the porcine hormone, which may explain the high potency and prolonged action of the salmon hormone in the rat.

The Preparation and Properties of Some Cyclic β-Diketone Diimines

1973 ◽  
Vol 51 (4) ◽  
pp. 505-513 ◽  
Author(s):  
Kenneth Charles Moss ◽  
Frank Price Robinson
Keyword(s):  
Spectral Data ◽  
Schiff Bases ◽  
Steric Hindrance ◽  
Condensation Reaction ◽  
Side Chain ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Aliphatic Diamines

The condensation reaction between a series of aliphatic diamines and a series of five- and six-membered cyclic β-diketones to form Schiff bases was investigated. Mass spectral data show that reaction occurred on the side-chain carbonyl except where steric hindrance forced condensation to occur on the ring carbonyl. N.m.r. studies show that these Schiff bases exist primarily in the ketamine form in solution, irrespective of the solvent. I.r. data confirm this. The preparation of a number of Cu(II) and Ni(II) complexes from some of the ligands is also described.

Long-acting antibacterial agents

1970 ◽  
Vol 8 (26) ◽  
pp. 101-103
Keyword(s):  
Plasma Proteins ◽  
Antibacterial Agents ◽  
Renal Excretion ◽  
Slow Release ◽  
Blood Levels ◽  
Prolonged Action ◽  
Procaine Penicillin ◽  
High Doses ◽  
Long Acting ◽  
Release Form

A number of antibacterial agents have recently been developed which are recommended because they need to be administered infrequently. Examples are Deteclo (Lederle), Kelfizine W (Pharmitalia), and Vibramycin (Pfizer). The advantage claimed for these preparations is that adequate blood levels can be maintained with infrequent dosage. A prolonged action may be achieved in various ways - for example, by using a mixture of antibiotics which are absorbed and excreted at different rates, as in Deteclo;1 by giving high doses of a well absorbed preparation which is slowly excreted, e. g. doxycycline (Vibramycin),2 by administration in a slow-release form, e. g. procaine penicillin; or by giving probenecid to lessen renal excretion. Where prolongation of action depends on increased binding to plasma proteins, the drug may be more likely to act as a hapten and so to induce allergic reactions.

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