Electron microscopic localization of adenylate cyclase activity of white and brown adipose tissue of the rat and chicken

1976 ◽  
Vol 50 (1) ◽  
pp. 57-64 ◽  
Author(s):  
L. Rechardt ◽  
H. Hervonen
Keyword(s):  
Adipose Tissue ◽  
Adenylate Cyclase ◽  
Brown Adipose Tissue ◽  
Cyclase Activity ◽  
Adenylate Cyclase Activity ◽  
Electron Microscopic ◽  
Microscopic Localization ◽  
Brown Adipose ◽  
Electron Microscopic Localization

Altered effect of insulin and catecholamines in brown adipose tissue of cold-acclimated rats

1979 ◽  
Vol 57 (3) ◽  
pp. 320-324 ◽  
Author(s):  
Nicole Bégin-Heick ◽  
Iris Noland ◽  
Marthe Dalpé ◽  
H. M. C. Heick
Keyword(s):  
Adipose Tissue ◽  
Plasma Membrane ◽  
Adenylate Cyclase ◽  
Brown Adipose Tissue ◽  
Cold Acclimation ◽  
Inhibitory Action ◽  
Cyclase Activity ◽  
Relative Response ◽  
Brown Adipose ◽  
Glucose Incorporation

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.

The effect of the divalent cations Mg2+ and Mn2+ on adenylate cyclase activity in white and brown adipose tissue of lean and obese (ob/ob) mice

1985 ◽  
Vol 63 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Nicole Bégin-Heick
Keyword(s):  
Adipose Tissue ◽  
Adenylate Cyclase ◽  
Brown Adipose Tissue ◽  
Divalent Cations ◽  
Cyclase Activity ◽  
Obese Mice ◽  
Brown Adipose ◽  
Maximal Activation ◽  
Excess Mg ◽  
Dose Dependent

The divalent cations Mg2+ and Mn2+ in excess of the concentrations required to complex with ATP (excess Mg2+ or Mn2+) modulate the activity of adenylate cyclase. As a substrate, Mn∙ATP was at least as effective as Mg∙ATP in supporting adenylate cyclase activity in white and brown adipose tissue membranes. Both excess Mg2+ and Mn2+ had quantitatively different effects on the enzyme of lean and ob/ob mice and qualitatively different effects in white and brown adipose tissue. In white adipocyte membranes excess Mg2+ increased basal activity, as well as activity owing to guanylylimidodiphosphate (Gpp(NH)p) (with or without isoproterenol) and NaF. Maximal activation by Gpp(NH)p + isoproterenol required a higher concentration of Mg2+ in tissue from ob/ob than lean mice. Excess Mn2+ prevented the activation of the enzyme by Gpp(NH)p or Gpp(NH)p + isoproterenol in a dose-dependent manner. Mn2+ inhibited even in the presence of maximally effective Mg2+ concentrations. The enzyme of the ob/ob mouse membrane required a significantly higher dose of Mn2+ to achieve 50% inhibition. In brown adipose tissue, specific activities of the isoproterenol + Gpp(NH)p and NaF stimulated enzyme were significantly lower in the obese mice under all conditions studied. Except that NaF-stimulated activity was increased significantly more in the membranes of lean mice by the combination of Mg2+ + Mn2+, these cations did not produce significantly different dose-dependent effects in membranes from lean and ob/ob mice. Maximal activation occurred at lower concentrations of MgCl2 (3–5 versus 10–20 mM) and required higher concentrations of MnCl2 (3–5 versus 1 mM) in brown than in white adipose tissue membranes. Furthermore, Mn2+ in excess of the concentration required to activate maximally produced little or no inhibitory effect on the brown adipose tissue enzyme. These studies illustrate the diversity of adenylate cyclase modulation in different tissues. Further studies with bacterial toxins will be necessary to verify whether there are differences in the equilibrium of association of the stimulatory and inhibitory components of guanine nucleotide regulatory proteins in tissues of lean and obese mice.

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
Keyword(s):  
Adipose Tissue ◽  
Linoleic Acid ◽  
Brown Adipose Tissue ◽  
Adenyl Cyclase ◽  
Neonatal Rat ◽  
Cyclase Activity ◽  
Fetal Life ◽  
Adenyl Cyclase Activity ◽  
High Linoleic Acid ◽  
Brown Adipose

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.

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