Search PubMed⌕ Search

Biomedical subjects

P Hahn

Publications and source records attributed to P Hahn.

At least 127 records · Page 7Linked to original sources
PubMed1984

Effect of litter size on plasma cholesterol and insulin and some liver and adipose tissue enzymes in adult rodents.

Rats and mice were raised in litters of 4 or 14 per mother. Plasma levels of cholesterol and insulin were found to be elevated later in life in those raised in small litters. Hepatic 3-hydroxy-3-methylglutaryl-CoA reductase activity in rats was higher in large than in small litters on day 60 but not on day 240. In adipose tissue activity was higher in the small litters. The activities of phosphoenolpyruvate carboxy-kinase in liver and of fatty acid synthetase in adipose tissue were higher in large than in small litters later in life. It is concluded that early quantitative changes in food intake have permanent late effects.

Adipose Tissue↗
PubMed1984

Fructose-1,6-biphosphatase activity in the intestinal mucosa of developing rats.

Fructose-biphosphatase (EC 3.1.3.11) activity was determined in the proximal and distal parts of the small intestinal mucosa of rats 1-30 days of age. Activity was found to increase to a maximum on about the 10th postnatal day and then to decrease. It was always higher in the proximal than in the distal portion of the gut. The enzyme showed a wide range of pH optimum around 7.0 and was inhibited by AMP. In 10-day-old rats activity determined 24 or 48 h after a single injection of cortisone or triiodothyronine was significantly decreased. This effect was no longer found for cortisone in 14-day-old animals. Weaning 18-day-old rats to a high-fat diet for 5 or 7 days delayed but did not prevent the usual decrease in activity seen at weaning.

Animal Population Groups↗
PubMed1984

Cholesterol oxidation and 7 alpha-hydroxylation during postnatal development of the rat.

The activity of rat hepatic cholesterol 7 alpha-hydroxylase is low in the suckling period and rises at weaning. The oxidation of intraperitoneally administered 26(-14)C-cholesterol to 14CO2 is also low in suckling rats and increases with age as does the radioactivity in the plasma. In contrast, propionic acid oxidation to CO2 is much more rapid, suggesting that the side chain cleavage of cholesterol is not a rate-limiting process.

Aging↗
PubMed1984

Oral L-carnitine administration after jejunoileal by-pass surgery.

Jejunoileal bypass surgery was performed on 14 morbidly obese women. Seven were treated with 3/g/day oral L-carnitine for ten days before surgery and for another ten days at six weeks following surgery. The other seven were not treated with carnitine. Carnitine administration was found to be without effect on plasma lipids, free fatty acids and ketones and on all other tested indicators. However, plasma levels of carnitine and the rate of urinary elimination of carnitine both after treatment and after an acute oral load were increased before and after surgery, indicating that carnitine was well absorbed by the shortened gut. Rate of elimination of short chain carnitine esters via the urine was also elevated after treatment. Surgery resulted in a marked decrease of plasma lipids but in no change in apolipoprotein A and B concentrations.

3-Hydroxybutyric Acid↗
PubMed1983

Regulation of phosphoenolpyruvate carboxykinase during postnatal development in the rat.

Phosphoenolpyruvate carboxykinase (EC 4.1.1.49) (PEPcK) activity is high in the liver, brown fat, and small intestinal mucosa of suckling rats. Starvation results in a rise in hepatic activity in newborn and older animals, but a fall in brown fat from rats younger than 14 days. At that age, activity rises in all three tissues on fasting. Both triiodothyronine (T3) and dexamethazone depress activity in gut and (as previously reported) in brown fat, but elevate it in liver. Cold exposure also has a similar effect. Both alpha-antagonist and agonist injections result in elevated hepatic activity. T3 given together with these more than doubles the effect of either drug or T3 given alone. In brown fat only antagonists decrease PEPcK activity, whereas in gut both agonists and antagonist have an inhibitory effect. It is concluded that PEPcK activity in the three tissues responds differently to the same stimuli with gut mucosa being more similar to, but not the same as, brown fat than to liver.

Adipose Tissue, Brown↗
PubMed1983

Cholesterol synthesis in the small intestine and adipose tissue of suckling rats: the effect of litter size.

Rats were raised in large (14/dam), medium (8/dam) and small (4/dam) litters. The rate of in vitro synthesis of cholesterol from 3H2O in the proximal and distal parts of the small intestine decreased from birth to a low 14 days later and then increased again by day 21. The rate of synthesis in both parts of the gut on day 6 after birth was lowest in the 14/dam group. On day 21 after birth the rate was highest in the 14/dam group in the proximal and lowest in the distal gut. Thus in the early postnatal period low rates of intestinal cholesterol synthesis correlate with low plasma cholesterol values. In white adipose tissue the low rate of cholesterol synthesis remained unaltered up to day 21 in the 8/dam, and 4/dam groups. However, it continuously increased in the 14/dam group being about threefold higher than in the other two groups on day 21.

Adipose Tissue↗
PubMed1983

Effect of intralipid on total and high-density lipoprotein cholesterol levels in newborns and infants.

Even in very small premature infants (less than 1,000 g) intravenous feeding with Intralipid results in an elevation of total and a fall of high-density lipoprotein (HDL) cholesterol levels. If oral feeding occurs while Intralipid is given, HDL cholesterol levels rise again. A positive correlation was found between levels of total cholesterol and the amount of fat administered. A negative relationship was evident between the level of total cholesterol and that of HDL and between the latter and the amount of fat consumed.

Cholesterol↗
PubMed1982

Phosphoenolpyruvate carboxykinase in the small intestine of developing rodents.

Phosphoenolpyruvate carboxykinase activity was found to be high in the mucosa of the small intestine of suckling rats. Activity was higher proximally than distally and decreased to very low values at weaning. After weaning, feeding a high fat diet or starvation did not result in elevation of the low intestinal activity in rats. However, in mice, who also showed high activity in the suckling period, starvation, but not diet, did cause a rise. Since fructose-diphosphatase was also found in the intestinal mucosa of suckling rats, it is suggested that gluconeogenesis may occur in this tissue in the neonatal period.

Aging↗
PubMed1982

3-Hydroxy-3-methylglutaryl-CoA reductase activity in liver, brown fat, and small intestine of developing rats.

3-Hydroxy-3-methylglutarylCoA reductase activity was found to be low in the microsomal fraction of the small intestine, liver, and brown fat in suckling rats. It was high perinatally. Treatment with phosphatase of the microsomal fraction increased activity considerably in gut, somewhat in liver, and not al all in brown fat of infant rats. Activity in the mitochondrial fraction of the small intestine showed no developmental changes. injections of infant rats with triiodothyronine increased and with cortisone decreased hepatic activity but had no effect on gut or brown fat. It is concluded that even though activity decreases in all three tissues after birth, it is regulated differently in liver than in gut and brown fat.

Acid Phosphatase↗
PubMed1982

The effect of 3,5,3'-triiodothyronine on phosphoenolpyruvate carboxykinase, fatty acid synthetase and malic enzyme activity of liver and brown fat of fetal and neonatal rats.

Pregnant rats were injected with triiodothyronine (T3) on the 19th and 20th days of pregnancy. This elevated fetal T3 plasma values and caused a large rise in fetal liver phosphoenolpyruvate carboxykinase (PEPcK) activity. At the same time PEPcK activity in fetal brown fat was inhibited. Essentially the same effect of T3 was also noted when injected into postnatal rats. T3 injections also elevated fatty acid synthetase activity in brown fat of weanling rats but, in contrast to corticosteroids, had no effect earlier in life. No effect was noted in the liver, except a slight decrease in the fetus. T3 injections to suckling rats elevated plasma levels of insulin and glucagon within 24 h.

Adipose Tissue, Brown↗
PubMed1981

The complete nucleotide sequence of an infectious clone of cauliflower mosaic virus by M13mp7 shotgun sequencing.

We have determined the complete primary structure (8031 base pairs) of an infectious clone of cauliflower mosaic virus strain CM1841. The sequence was obtained using the strategy of cloning shotgun restriction fragments in the sequencing vector M13mp7. Comparison of the CM1841 sequence with that published for another caMV strain (Strasbourg) reveals 4.4% changes, mostly nucleotide substitutions with a few small insertions and deletions. The six open reading frames in the sequence of the Strasbourg isolate are also present in CM1841.

Base Sequence↗
PubMed1981

Plasma carnitine in pregnancy.

Plasma levels of total and free carnitine and acylcarnitine were determined in women pregnant for 28 to 42 weeks, and also in some of their fetuses. The finding was that the levels not only of free but also of total carnitine were very low in pregnancy. They were somewhat elevated in women with essential hypertension. Levels of acylcarnitine were significantly decreased in gestational diabetics, presumably because these women were treated with insulin. In nine cases examined, plasma levels of total and free carnitine and acylcarnitine were significantly higher in the fetuses than in their mothers.

Adolescent↗
PubMed1981

Tumor shedding and coagulation.

Three syngeneic carcinomas from two species shed plasma membrane vesicles when cultured in vitro or grown in the ascites tumor form in vivo. Shed vesicles carry procoagulant activity that can account for the activation of the clotting system and the fibrin deposition associated with these and many other types of malignancy in animals and man.

Animals↗
PubMed1981

Cyclic nucleotides in breast milk.

Adenosine 3':5' monophosphate3 (cAMP) and guanosine 3':5' monophosphate (cGMP) are known to participate in the regulation of proliferation and differentiation, the processes intimately associated with maturation of the neonate. We have therefore examined their content in the physiological nutrient of the mammalian neonate, the mother's milk. Widely fluctuating concentrations between 0.1 and 0.7, and between 0.01 and 0.15 nmol/ml, were found for cyclic AMP and cyclic GMP, respectively. Concentrations in human breast milk changed during the 5-to 15-min period of one nursing, during any 24-h period, and also during the total lactation period. Levels of cyclic GMP were generally less fluctuating and were lower during afternoon and evening; they were relatively high at the start of lactation and levelled off during the postpartum period. The ratio of the two cyclic nucleotides also fluctuated widely and was significantly different from the ratio determined on blood plasma collected at the same time. Oxytocin injection had no effect on cyclic AMP content of rat milk. The stomach content of the nucleotide in rat pups remained high for at least 1 h after suckling indicating that cyclic nucleotides remain available for intestinal absorption; whether they have any physiological function in the neonate will have to emerge from further studies.

Animals↗
PubMed1981

Brown adipose tissue and carnitine in cold-adapted rats.

Cold-adapted (CA) and warm-adapted (WA) rats (5 and 28 degrees C) were infused with noradrenaline (4 microgram.kg-1.min-1) for 15 min. Blood was collected from Sulzer's vein coming from brown adipose tissue and analyzed for total carnitine, free carnitine, and beta-hydroxybutyrate content, before and up to 45 min after the infusion. Acylcarnitine (total minus free carnitine) levels increased more and total carnitine levels decreased more in the CA group than in the WA group. beta-Hydroxybutyrate content increased to the same extent (from about 0.16 to 0.8 mM) in both groups. Brown fat was found not to release carnitine into the circulation after NA infusion. Twenty minutes after the end of the infusion brown fat retained both ketones and acylcarnitine in the CA rats only.

Acclimatization↗