Young castrated male goats (n = 8) were used to investigate the effect of long-term treatment with recombinant methionyl bovine somatotropin in a sustained release vehicle (bST; 100 mg at seven-day intervals in a 147-day experiment) and chronic culture (24 h) of omental adipose tissue in the presence of various hormones on lipogenic responses to catecholamines during acute incubation (2 h) in a sodium acetate supplemented glucose-free buffer. The rate of fatty acid synthesis in freshly-prepared adipose explants was low and did not differ from those cultured in the absence of hormones for 24 h. Hormonal combination of insulin (17 nmol.l-1) plus cortisol (138 nmol.l-1) or insulin plus recombinant enterokinase linker bST (4.5 nmol.l-1) increased lipogenesis (P<0.05). Further addition of bST or cortisol decreased lipogenesis significantly (P<0.05) in the controls but not significantly in bST-treated animals. Cultured explants from either control or bST-treated animals showed significant inhibition of lipogenesis by both norepinephrine (10 m mol.l-1) and isoprenaline (10 m mol.l-1). BST treatment in vivo did not increase the responsiveness of cultured explants to norepinephrine in vitro, however, the responsiveness to isoprenaline(inhibition of lipogenesis) was greater in bST-treated animals than in the controls., J. Škarda., and Obsahuje bibliografii
Adenosine is secreted from adipocytes, binds to adenosine A1 receptor and modulates various functions of these cells. In the present study, the effects of an adenosine A1 receptor antagonist (DPCPX; 0.01, 0.1 and 1 μM) on lipogenesis, glucose transport, lipolysis and the antilipolytic action of insulin were tested in rat adipocytes. DPCPX had a very weak effect on lipogenesis and did not significantly affect glucose uptake. In adipocytes incubated with 1 μM DPCPX, lipolysis increased. This effect was blunted by insulin and by a direct inhibitor of protein kinase A. Moreover, 0.1 μM DPCPX substantially enhanced the lipolytic response to epinephrine and increased cAMP in adipocytes. However, DPCPX was ineffective when lipolysis was stimulated by direct activation of protein kinase A. Adipocyte exposure to epinephrine and insulin with or without 0.1 μM DPCPX demonstrated that this antagonist increased the release of glycerol. However, despite the presence of DPCPX, insulin was able to reduce lipolysis. It is concluded that DPCPX had a weak effect on lipogenesis, whereas lipolysis was significantly affected. The partial antagonism of adenosine A1 receptor increased lipolysis in cells incubated with epinephrine alone and epinephrine with insulin due to the synergistic action of 0.1 μM DPCPX and epinephrine., T. Szkudelski, K. Szkudelska, L. Nogowski., and Obsahuje seznam literatury
Perinatal (1-2 days of age) and one-month-old (24-32 days of age) male goats were used to investigate the effect of age and long-term culture (24 h) of perirenal and omental adipose explants in the presence of insulin, cortisol and bovine somatotropin (alone or in different combinations) on net glucose-stimulated lipogenesis (NGSL, i.e. the rate of lipogenesis in the presence of glucose minus the rate of lipogenesis in the absence of glucose) in the absence and in the presence of catecholamines in acute incubations (2 h). Mean values of NGSL in both freshly prepared and cultured explants were consistently lower in perinatal than in one-month-old goats. Cortisol alone decreased and combinations of insulin plus cortisol increased NGSL in perirenal explants of one-month-old animals. When perirenal explants from these one-month-old goats were cultured in the presence of insulin plus cortisol plus bovine somatotropin, the rates of lipogenesis were lower than those in cultures with insulin plus cortisol. No such effects of these hormones were noted in omental explants of both perinatal and one-month-old animals. In freshly prepared perirenal and omental explants, the rates of NGSL were inhibited by isoprenaline in tissues of both groups of animals and by noradrenaline in omental tissues of animals of the older group only. The mean values of NGSL in cultured explants of perinatal animals were not affected by noradrenaline. Isoprenaline inhibited NGSL in omental but not in perirenal tissue. In older animals the rates of NGSL were decreased by both noradrenaline and isoprenaline in perirenal and omental adipose tissues. Isoprenaline was more effective than noradrenaline in perirenal adipose tissue., J. Škarda., and Obsahuje bibliografii
The simultaneous effect of intermittent starvation and a high-fat diet were investigated in mice after several weeks of experimental feeding. The animals adapted to intermittent fasting fed a high-fat diet showed a lower degree of hyperphagia than animals adapted to intermittent fasting fed a standard laboratory diet. The weight of both individual portions of the stomach was elevated in adapted animals fed both a standard laboratory diet and the high-fat diet. The weight of the small intestine was increased in adapted animals fed a high-fat diet. The length of the small intestine was not changed after 8 weeks of intermittent starvation in both adapted groups (standard laboratory diet, high-fat diet). A higher amount of body fat was found in both groups of animals adapted to intermittent fasting (standard laboratory diet, high-fat diet) but adapted animals fed a high-fat diet showed less body fat than adapted animals fed a standard laboratory diet. Lower levels of serum lipids were found in adapted animals fed a high-fat diet. These results suggest that both lipogenesis and lipid oxidation are accentuated by intermittent starvation and a high-fat diet act concomitantly.
Effects of early neonatal interventions on metabolic parameters later in life (s.c. late effects) were studied in rats using two models; namely, (a) the effects of premature weaning and (b) the effects of "dietary" manipulations during the suckling period (s.c. small vs. large litters), (a) Premature weaning of rats caused an earlier degeneration of spermiogenesis and elevated plasma cholesterol levels in adult animals when compared to levels found in animals weaned 12 days later (on day 30 after birth). In adult rats, radioiodine uptake in thyroid glands was lower in the group weaned prematurely. Premature weaning was followed by a decrease of corticosterone production in adrenal glands in adult animals; in female adult prematurely weaned rats, an elevated response of adrenal cortex to stressors was observed. Several other studies explored the "immediate" effects of early, premature weaning, (b) Early exposure to high fat diet evoked a hypercholesterolaemic response in adulthood following brief exposure to HF diet. Rats from litters reduced to 3 or 4 pups per mother on postnatal day 3 exhibited 2 days later plasma levels of cholesterol higher than in rats raised in large litters of 8 or 14. The difference between small and large litters was preserved for the whole lifespan of the animals. In adulthood, rats from small litters were fatter and had higher levels of plasma cholesterol and insulin. Other studies suggester that early dietary experience may regulate the pattern of drug metabolism in adult life. An inhibition of diurnal plasma corticosterone variation was found in rats overfed during the neonatal period and an increased stimulation of lipolysis by norepinephrine and lipogenesis by insulin was demonstrated in neonatally underfed rats. Interesting studies were reported in longitudinally studies in children: at the age of 9-12 year brest-fed children (for more than 6 months) had the highest cholesterol levels; on the other hand significantly increased levels of APO B, Apo Al, ATH index and Apo/B Apo A1 quotient (p<0.05) were found in the nonbreast-fed group (27 references).