Effect of the linoleic acid concentration of mother's diet on adenyl cyclase activity of fetal and neonatal rat brown adipose tissue

1977 ◽  
Vol 55 (6) ◽  
pp. 1242-1245 ◽  
Author(s):  
Thierry Cresteil

An adenyl cyclase activity was measurable in the brown adipose tissue of fetal rat, and could be stimulated in vitro by noradrenaline during the last 3 days of fetal life. The stimulating effect of noradrenaline was maximal at birth and decreased during the first days of extrauterine life.Ingestion by mothers of a high lipid diet modified the developmental pattern of fetal adenyl cyclase. The linoleic acid content of mother's diet had no effect on the noradrenaline- or fluoride-stimulated specific activities except on the day 22 of gestation. Relative noradrenaline-stimulated activity, expressed as a fraction of the maximal activity, was significantly increased in fetuses and 1-day-old newborns from mothers fed a high linoleic acid diet, but no effect was observed in suckling newborns.

1971 ◽  
Vol 49 (7) ◽  
pp. 802-810 ◽  
Author(s):  
Michelle Muirhead ◽  
Jean Himms-Hagen

Adenyl cyclase of interscapular brown adipose tissue of rats undergoing acclimation to cold was measured in order to find out whether the amount of the nor adrenaline-stimulated enzyme might be increased in cold-acclimated rats, in which a characteristic large increase in the overall calorigenic response to noradrenaline (nonshivering thermogenesis) is induced by the prolonged exposure to cold (4–8 weeks). It was found that the growth of the brown adipose tissue in the acclimating rats is accompanied by an increase in the total amount of noradrenaline-stimulated adenyl cyclase activity. Since this increase does not keep pace with the growth of the tissue a reduction in specific activity of the noradrenaline-stimulated adenyl cyclase was observed. Thus no evidence was obtained for an increased concentration of noradrenaline-responsive structures in the cell membrane of the brown adipose tissue of cold-acclimated rats.In contrast, fluoride-stimulated adenyl cyclase activity increased almost twofold after only 2 days of exposure to cold and before the growth of the tissue had started. Thereafter the activity of this enzyme increased in parallel to the growth of the tissue. The extra activity that developed during the first 2 days persisted throughout the period of acclimation to cold (8 weeks); it disappeared within 1 day when the cold-acclimated rats were returned to room temperature.These changes in adenyl cyclase activity are more rapid than any hitherto reported. They presumably reflected a change in the properties of the cell membrane in response to an environmental stress. It is not known whether the increase in measurable fluoride-stimulated adenyl cyclase activity reflects an increase in the synthesis of a specific protein or an unmasking of the activity of an enzyme already present.No change in the specific activity of cyclic AMP phosphodiesterase was observed; during acclimation to cold the total amount of this enzyme increased in parallel with the growth of the tissue.


1989 ◽  
Vol 257 (5) ◽  
pp. E625-E631 ◽  
Author(s):  
M. J. Obregon ◽  
C. Ruiz de Ona ◽  
A. Hernandez ◽  
R. Calvo ◽  
F. Escobar del Rey ◽  
...  

Brown adipose tissue (BAT) iodothyronine 5'-deiodinase (5'D) activities are very high during fetal life but decrease 10-fold a few hours before birth. Accordingly, BAT 3,5,3'-triiodothyronine (T3) concentrations are also very high. The temporal patterns of changes in BAT 5'-D and fetal plasma insulin are similar (and differ from the pattern for catecholamines) but are not superimposable. A causal role for insulin in the activation of fetal BAT 5'-D is therefore not supported by the data. Maternal thyroidectomy leads to a decrease in the total and relative weight of fetal BAT and to a 30-50% increase in BAT 5'-D activities; BAT thyroid hormone concentrations are essentially unchanged. Fetal hypothyroidism was induced by giving methimazole and resulted in a marked decrease of BAT thyroxine (T4) and T3 concentrations. This treatment increased BAT 5'-D activity only on day 21 of gestation, but no effect was observed on day 20. The fetal 5'-D response to thyroid hormones infused into the methimazole-treated dams was studied at 21 days of gestation. The increase in BAT 5'-D induced by methimazole treatment was prevented by T4 infused into control dams but not by T3. In fetuses from thyroidectomized dams, the pattern of 5'-D regulation by thyroid hormones was impaired. It is suggested that the high concentrations of thyroid hormones present in fetal BAT might participate in the general maturation and development of fetal BAT.


1994 ◽  
Vol 302 (3) ◽  
pp. 695-700 ◽  
Author(s):  
C Manchado ◽  
P Yubero ◽  
O Viñas ◽  
R Iglesias ◽  
F Villarroya ◽  
...  

CCAAT/enhancer-binding protein (C/EBP) alpha mRNA and its protein products C/EBP alpha and 30 kDa C/EBP alpha are expressed in rat brown-adipose tissue. Results also demonstrate the expression of C/EBP beta mRNA and its protein products C/EBP beta and liver inhibitory protein (LIP) in the tissue. The abundance of C/EBP alpha and C/EBP beta proteins in adult brown fat is similar to that found in adult liver. However, the expression of C/EBP alpha and C/EBP beta is specifically regulated in brown fat during development. C/EBP alpha, 30 kDa C/EBP alpha, C/EBP beta and LIP content is several-fold higher in fetal brown fat than in the adult tissue, or liver at any stage of development. Peak values are attained in late fetal life, in concurrence with the onset of transcription of the uncoupling protein (UCP) gene, the molecular marker of terminal brown-adipocyte differentiation. When adult rats are exposed to a cold environment, which is a physiological stimulus of brown-adipose tissue hyperplasia and UCP gene expression, a specific rise in C/EBP beta expression with respect to C/EBP alpha, 30 kDa C/EBP alpha and LIP is observed. Present data suggest that the C/EBP family of transcription factors has an important role in the development and terminal differentiation of brown-adipose tissue.


1976 ◽  
Vol 231 (3) ◽  
pp. 700-706 ◽  
Author(s):  
SA Fink ◽  
JA Williams

Adrenergic receptors mediating depolarization in in vitro neonatal rat brown adipose tissue (BAT) have been characterized by use of adrenergic agonists and antagonists. Releasable endogenous catecholamine was present in BAT as demonstrated by tyramine- and 1,1-dimethyl-4-phenylpiperazinium iodide- (DMPP) induced depolarization in BAT from normal rats and its absence when BAT from reserpinized rats was used. In BAT from reserpinized rats l-norepinephrine, l-phenylephrine, and l-isoproterenol all similarly depolarized the bronw adipocytes over the concentration range of 10(-8) to 10(-6) M with a maximal depolarization of about 25 mV. Dopamine and d-norepinephrine were more than 100 times less potent. The beta-adrenergic blocker propranolol competitively inhibited isoproterenol-induced depolarization, whereas the alpha-adrenergic blackers, phentolamine and phenoxybenzamine, inhibited the phenylephrine-induced depolarization with much smaller inhibitory effects on the isoproterenol-induced depolarization. Both phenylephrine and isoproterenol elicited transient depolarizations when briefly added to the bathing medium while continuously recording from the same cell. Both the agonist and antagonist studies are interpreted as indicating the presence of both alpha- and beta-adrenergic receptors on BAT cells which mediate catecholamine-induced depolarization.


Nutrients ◽  
2009 ◽  
Vol 1 (2) ◽  
pp. 178-196 ◽  
Author(s):  
Alan Sneddon ◽  
D. Vernon Rayner ◽  
Sharon Mitchell ◽  
Shabina Bashir ◽  
Jung-Heun Ha ◽  
...  

2002 ◽  
Vol 174 (3) ◽  
pp. 427-433 ◽  
Author(s):  
H Budge ◽  
A Mostyn ◽  
V Wilson ◽  
A Khong ◽  
AM Walker ◽  
...  

The present study determines whether maternal administration of prolactin (PRL) to dams promotes the abundance of the brown adipose tissue-specific uncoupling protein-1 (UCP1) in fetal and neonatal rat pups. Recombinant PRL (24 micro g/kg per day), or an equivalent volume of saline, were infused into dams (n=19 per group) throughout pregnancy from 12 h after mating. Interscapular brown adipose tissue was sampled either from fetuses at 19.5 days of gestation (term=21.5 days) or from neonatal rat pups at approximately 18 h after birth. The abundance of UCP1 was determined by immunoblotting on adipose tissue samples from individual pups and pooled from groups of pups. This analysis was complemented by immunocytochemistry on representative adipose tissue samples. Maternal PRL infusion resulted in a greater abundance of UCP1 in fetal rats at 19.5 days of gestation (control: 97.2+/-8.4% reference; PRL: 525.6+/-74.4% reference; P<0.001) and in neonates 18 h after birth. In contrast, the abundance of the outer mitochondrial membrane protein voltage-dependent anion channel was unaffected by PRL. Neonatal adipose tissue sampled from pups born to PRL-infused dams possessed fewer lipid droplets, but more UCP1, as determined by immunocytochemistry. Fetal, but not maternal, plasma leptin concentrations were also increased by maternal PRL administration. In conclusion, as rats are altricial, and the potential thermogenic activity of brown adipose tissue develops over the first few days of postnatal life, these changes prior to, and at the time of, birth implicate PRL in fetal and neonatal adipose tissue maturation.


1989 ◽  
Vol 256 (1) ◽  
pp. R146-R154 ◽  
Author(s):  
C. Carneheim ◽  
B. Cannon ◽  
J. Nedergaard

Because brown adipose tissue lipids are the preferred substrate for thermogenesis during arousal from hibernation, the fatty acid composition of brown fat lipids was followed during cold acclimation and during a hibernation bout. In control golden hamsters (living at 22 degrees C), the fatty acid composition of the white adipose tissue closely resembled that of the food, but brown adipose tissue contained more animal-derived fatty acids. As an effect of acclimation to cold, the fatty acid composition of brown adipose tissue changed to resemble that of the food, and no marked differences between white and brown adipose tissue were then evident. During a hibernation bout, a major part of the fatty acids accumulated in brown fat during entry into hibernation consisted of "rare" acids, such as homo-gamma-linoleic acid. Homo-gamma-linoleic, together with eicosadienoic acid and lignoceric acid, was preferentially utilized during the early phase of arousal. During this phase, "bulk" fatty acids, such as linoleic acid, were spared, whereas in late arousal, linoleic acid was the preferred substrate. It was concluded that rare fatty acids are of quantitative significance in brown adipose tissue during hibernation and arousal.


1979 ◽  
Vol 57 (3) ◽  
pp. 320-324 ◽  
Author(s):  
Nicole Bégin-Heick ◽  
Iris Noland ◽  
Marthe Dalpé ◽  
H. M. C. Heick

Data are presented indicating that in brown adipose tissue (BAT) of cold-acclimated (CA), but not cold-exposed (CE) rats, there was an alteration in the relative response to catecholamines and insulin as evidenced by increased binding of alprenolol and decreased binding of insulin to plasma membrane enriched fractions. In addition, the stimulatory effect of insulin on glucose incorporation into glycogen and its inhibitory action on adenylate cyclase activity were both blunted in the CA tissues. It is proposed that shifts in the capacity of BAT to respond to catecholamines and insulin may be involved in the mechanism of cold acclimation.


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