Abstract
This study was undertaken to determine whether receptor and non-receptor components of the adenylate cyclase (AC) cascade were altered in brown adipose tissue (BAT) of 14-day-old pre-obese (fa/fa) rats, before endocrine status is strongly modified by fa gene expression. Activity of the AC catalytic subunit did not differ between the two genotypes. In fa/fa rats compared with control Fa/fa rats, there was a 50% decrease in the activity of alpha Gs (stimulated by NaF or guanosine 5'-[gamma-thio]triphosphate) but no change in protein content (Western blotting). alpha Gi function, assessed by the inhibitory action of low concentrations of guanosine 5'-[beta gamma-imido]triphosphate upon 10(-4) M forskolin-stimulated AC activity, was equally low in both genotypes. Analysis of dose-response curves for different beta-agonists revealed that (i) both the basal and the maximally stimulated activity of AC were 2-fold lower in fa/fa rats than in Fa/fa rats; (ii) BRL37344 and CGP12177 (beta 3 agonists) were less potent in fa/fa than in Fa/fa rats (Kact. multiplied by 2); (iii) noradrenaline and isoprenaline (Iso), at the low-affinity site (beta 3-AR), were less potent in fa/fa than in Fa/fa pups (Kact. increased by 30 and 20% respectively). At the high-affinity site (mainly beta 1) these two agonists were more potent in fa/fa than in Fa/fa rats (Kact. decreased by 40 and 80% respectively). In good agreement with the latter result, the beta 1-adrenergic receptor (beta 1-AR)-selective antagonist CGP20712A had more effect on the Iso-stimulated AC activity in pre-obese than in lean pups (2-fold decreased in IC50). Binding experiments with [3H]CGP12177 show that in BAT of suckling rats, beta 3-ARs represent 80% of the total beta-ARs. Bmax values for the two sites were not affected by the genotype, although the beta 3-AR mRNA concentration in BAT (quantitative reverse-transcriptase PCR) was 3-fold lower in fa/fa rats than in Fa/fa pups. In conclusion, these results provide evidence for alterations in beta 1- and beta 3-AR signalling in BAT of 14-day-old suckling pre-obese Zucker rats with a decreased activity of alpha Gs. The impaired AC responsiveness to catecholamines might be a primary contributor to the development of this genetic obesity.
Full text
PDF![781](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/730b/1136182/7dfcc57161e6/biochemj00049-0132.png)
![782](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/730b/1136182/7a42d8d8b284/biochemj00049-0133.png)
![783](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/730b/1136182/c7ab6f1cdc74/biochemj00049-0134.png)
![784](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/730b/1136182/72d1b2932cc2/biochemj00049-0135.png)
![785](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/730b/1136182/60ae7ca27f69/biochemj00049-0136.png)
![786](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/730b/1136182/ac1ef6e1b07d/biochemj00049-0137.png)
![787](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/730b/1136182/2ef61a0301f0/biochemj00049-0138.png)
![788](https://cdn.ncbi.nlm.nih.gov/pmc/blobs/730b/1136182/98b350a278d5/biochemj00049-0139.png)
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Arch J. R., Ainsworth A. T., Cawthorne M. A., Piercy V., Sennitt M. V., Thody V. E., Wilson C., Wilson S. Atypical beta-adrenoceptor on brown adipocytes as target for anti-obesity drugs. Nature. 1984 May 10;309(5964):163–165. doi: 10.1038/309163a0. [DOI] [PubMed] [Google Scholar]
- Avruch J., Wallach D. F. Preparation and properties of plasma membrane and endoplasmic reticulum fragments from isolated rat fat cells. Biochim Biophys Acta. 1971 Apr 13;233(2):334–347. doi: 10.1016/0005-2736(71)90331-2. [DOI] [PubMed] [Google Scholar]
- Bazin R., Eteve D., Lavau M. Evidence for decreased GDP binding to brown-adipose-tissue mitochondria of obese Zucker (fa/fa) rats in the very first days of life. Biochem J. 1984 Jul 1;221(1):241–245. doi: 10.1042/bj2210241. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
- Bray G. A., York D. A. Hypothalamic and genetic obesity in experimental animals: an autonomic and endocrine hypothesis. Physiol Rev. 1979 Jul;59(3):719–809. doi: 10.1152/physrev.1979.59.3.719. [DOI] [PubMed] [Google Scholar]
- Bégin-Heick N. Absence of the inhibitory effect of guanine nucleotides on adenylate cyclase activity in white adipocyte membranes of the ob/ob mouse. Effect of the ob gene. J Biol Chem. 1985 May 25;260(10):6187–6193. [PubMed] [Google Scholar]
- Bégin-Heick N. Alpha-subunits of Gs and Gi in adipocyte plasma membranes of genetically diabetic (db/db) mice. Am J Physiol. 1992 Jul;263(1 Pt 1):C121–C129. doi: 10.1152/ajpcell.1992.263.1.C121. [DOI] [PubMed] [Google Scholar]
- Bégin-Heick N. Quantification of the alpha and beta subunits of the transducing elements (Gs and Gi) of adenylate cyclase in adipocyte membranes from lean and obese (ob/ob) mice. Biochem J. 1990 May 15;268(1):83–89. doi: 10.1042/bj2680083. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chaudhry A., Granneman J. G. Developmental changes in adenylyl cyclase and GTP binding proteins in brown fat. Am J Physiol. 1991 Aug;261(2 Pt 2):R403–R411. doi: 10.1152/ajpregu.1991.261.2.R403. [DOI] [PubMed] [Google Scholar]
- Chaudhry A., MacKenzie R. G., Georgic L. M., Granneman J. G. Differential interaction of beta 1- and beta 3-adrenergic receptors with Gi in rat adipocytes. Cell Signal. 1994 May;6(4):457–465. doi: 10.1016/0898-6568(94)90093-0. [DOI] [PubMed] [Google Scholar]
- Collins S., Daniel K. W., Rohlfs E. M., Ramkumar V., Taylor I. L., Gettys T. W. Impaired expression and functional activity of the beta 3- and beta 1-adrenergic receptors in adipose tissue of congenitally obese (C57BL/6J ob/ob) mice. Mol Endocrinol. 1994 Apr;8(4):518–527. doi: 10.1210/mend.8.4.7914350. [DOI] [PubMed] [Google Scholar]
- D'Allaire F., Atgié C., Mauriège P., Simard P. M., Bukowiecki L. J. Characterization of beta 1- and beta 3-adrenoceptors in intact brown adipocytes of the rat. Br J Pharmacol. 1995 Jan;114(2):275–282. doi: 10.1111/j.1476-5381.1995.tb13223.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Emorine L. J., Marullo S., Briend-Sutren M. M., Patey G., Tate K., Delavier-Klutchko C., Strosberg A. D. Molecular characterization of the human beta 3-adrenergic receptor. Science. 1989 Sep 8;245(4922):1118–1121. doi: 10.1126/science.2570461. [DOI] [PubMed] [Google Scholar]
- Engfeldt P., Hellmér J., Wahrenberg H., Arner P. Effects of insulin on adrenoceptor binding and the rate of catecholamine-induced lipolysis in isolated human fat cells. J Biol Chem. 1988 Oct 25;263(30):15553–15560. [PubMed] [Google Scholar]
- Fève B., Elhadri K., Quignard-Boulangé A., Pairault J. Transcriptional down-regulation by insulin of the beta 3-adrenergic receptor expression in 3T3-F442A adipocytes: a mechanism for repressing the cAMP signaling pathway. Proc Natl Acad Sci U S A. 1994 Jun 7;91(12):5677–5681. doi: 10.1073/pnas.91.12.5677. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fève B., Emorine L. J., Briend-Sutren M. M., Lasnier F., Strosberg A. D., Pairault J. Differential regulation of beta 1- and beta 2-adrenergic receptor protein and mRNA levels by glucocorticoids during 3T3-F442A adipose differentiation. J Biol Chem. 1990 Sep 25;265(27):16343–16349. [PubMed] [Google Scholar]
- Fève B., Emorine L. J., Lasnier F., Blin N., Baude B., Nahmias C., Strosberg A. D., Pairault J. Atypical beta-adrenergic receptor in 3T3-F442A adipocytes. Pharmacological and molecular relationship with the human beta 3-adrenergic receptor. J Biol Chem. 1991 Oct 25;266(30):20329–20336. [PubMed] [Google Scholar]
- Giacobino J. P. Subcellular fractionation of brown adipose tissue. J Supramol Struct. 1979;11(4):445–449. doi: 10.1002/jss.400110403. [DOI] [PubMed] [Google Scholar]
- Gilman A. G. G proteins: transducers of receptor-generated signals. Annu Rev Biochem. 1987;56:615–649. doi: 10.1146/annurev.bi.56.070187.003151. [DOI] [PubMed] [Google Scholar]
- Granneman J. G., Lahners K. N. Differential adrenergic regulation of beta 1- and beta 3-adrenoreceptor messenger ribonucleic acids in adipose tissues. Endocrinology. 1992 Jan;130(1):109–114. doi: 10.1210/endo.130.1.1309320. [DOI] [PubMed] [Google Scholar]
- Houslay M. D., Gawler D. J., Milligan G., Wilson A. Multiple defects occur in the guanine nucleotide regulatory protein system in liver plasma membranes of obese (fa/fa) but not lean (Fa/Fa) Zucker rats: loss of functional Gi and abnormal Gs function. Cell Signal. 1989;1(1):9–22. doi: 10.1016/0898-6568(89)90016-8. [DOI] [PubMed] [Google Scholar]
- Houslay M. D. Gi-2 is at the centre of an active phosphorylation/dephosphorylation cycle in hepatocytes: the fine-tuning of stimulatory and inhibitory inputs into adenylate cyclase in normal and diabetic states. Cell Signal. 1991;3(1):1–9. doi: 10.1016/0898-6568(91)90002-c. [DOI] [PubMed] [Google Scholar]
- Krief S., Bazin R., Dupuy F., Lavau M. Role of brown adipose tissue in glucose utilization in conscious pre-obese Zucker rats. Biochem J. 1989 Oct 1;263(1):305–308. doi: 10.1042/bj2630305. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Krief S., Bazin R. Genetic obesity: is the defect in the sympathetic nervous system? A review through developmental studies in the preobese Zucker rat. Proc Soc Exp Biol Med. 1991 Oct;198(1):528–538. doi: 10.3181/00379727-198-43286c. [DOI] [PubMed] [Google Scholar]
- Krief S., Fève B., Baude B., Zilberfarb V., Strosberg A. D., Pairault J., Emorine L. J. Transcriptional modulation by n-butyric acid of beta 1-, beta 2-, and beta 3-adrenergic receptor balance in 3T3-F442A adipocytes. J Biol Chem. 1994 Mar 4;269(9):6664–6670. [PubMed] [Google Scholar]
- Körtner G., Petrova O., Vogt S., Schmidt I. Sympathetically and nonsympathetically mediated onset of excess fat deposition in Zucker rats. Am J Physiol. 1994 Dec;267(6 Pt 1):E947–E953. doi: 10.1152/ajpendo.1994.267.6.E947. [DOI] [PubMed] [Google Scholar]
- Lafontan M., Berlan M. Fat cell adrenergic receptors and the control of white and brown fat cell function. J Lipid Res. 1993 Jul;34(7):1057–1091. [PubMed] [Google Scholar]
- Lavau M., Bazin R. Inguinal fat pad weight plotted versus body weight as a method of genotype identification in 16-day-old Zucker rats. J Lipid Res. 1982 Aug;23(6):941–943. [PubMed] [Google Scholar]
- Levitzki A. From epinephrine to cyclic AMP. Science. 1988 Aug 12;241(4867):800–806. doi: 10.1126/science.2841758. [DOI] [PubMed] [Google Scholar]
- Marie V., Dupuy F., Bazin R. Decreased T4-to-T3 conversion in brown adipose tissue of Zucker fa/fa pups before the onset of obesity. Am J Physiol. 1992 Jul;263(1 Pt 1):E115–E120. doi: 10.1152/ajpendo.1992.263.1.E115. [DOI] [PubMed] [Google Scholar]
- Mitchell F. M., Griffiths S. L., Saggerson E. D., Houslay M. D., Knowler J. T., Milligan G. Guanine-nucleotide-binding proteins expressed in rat white adipose tissue. Identification of both mRNAs and proteins corresponding to Gi1, Gi2 and Gi3. Biochem J. 1989 Sep 1;262(2):403–408. doi: 10.1042/bj2620403. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Muzzin P., Revelli J. P., Fraser C. M., Giacobino J. P. Radioligand binding studies of the atypical beta 3-adrenergic receptor in rat brown adipose tissue using [3H]CGP 12177. FEBS Lett. 1992 Feb 24;298(2-3):162–164. doi: 10.1016/0014-5793(92)80046-j. [DOI] [PubMed] [Google Scholar]
- Muzzin P., Revelli J. P., Kuhne F., Gocayne J. D., McCombie W. R., Venter J. C., Giacobino J. P., Fraser C. M. An adipose tissue-specific beta-adrenergic receptor. Molecular cloning and down-regulation in obesity. J Biol Chem. 1991 Dec 15;266(35):24053–24058. [PubMed] [Google Scholar]
- Nahmias C., Blin N., Elalouf J. M., Mattei M. G., Strosberg A. D., Emorine L. J. Molecular characterization of the mouse beta 3-adrenergic receptor: relationship with the atypical receptor of adipocytes. EMBO J. 1991 Dec;10(12):3721–3727. doi: 10.1002/j.1460-2075.1991.tb04940.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Planche E., Joliff M., Bazin R. Energy expenditure and adipose tissue development in 2- to 8-day-old Zucker rats. Int J Obes. 1988;12(4):353–360. [PubMed] [Google Scholar]
- Ros M., Northup J. K., Malbon C. C. Adipocyte G-proteins and adenylate cyclase. Effects of adrenalectomy. Biochem J. 1989 Feb 1;257(3):737–744. doi: 10.1042/bj2570737. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ros M., Northup J. K., Malbon C. C. Steady-state levels of G-proteins and beta-adrenergic receptors in rat fat cells. Permissive effects of thyroid hormones. J Biol Chem. 1988 Mar 25;263(9):4362–4368. [PubMed] [Google Scholar]
- Strassheim D., Palmer T., Milligan G., Houslay M. D. Alterations in G-protein expression and the hormonal regulation of adenylate cyclase in the adipocytes of obese (fa/fa) Zucker rats. Biochem J. 1991 May 15;276(Pt 1):197–202. doi: 10.1042/bj2760197. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Truett G. E., Bahary N., Friedman J. M., Leibel R. L. Rat obesity gene fatty (fa) maps to chromosome 5: evidence for homology with the mouse gene diabetes (db). Proc Natl Acad Sci U S A. 1991 Sep 1;88(17):7806–7809. doi: 10.1073/pnas.88.17.7806. [DOI] [PMC free article] [PubMed] [Google Scholar]
- YONETANI T., RAY G. S. STUDIES ON CYTOCHROME OXIDASE. VI. KINETICS OF THE AEROBIC OXIDATION OF FERROCYTOCHROME C BY CYTOCHROME OXIDASE. J Biol Chem. 1965 Aug;240:3392–3398. [PubMed] [Google Scholar]
- Zhang Y., Proenca R., Maffei M., Barone M., Leopold L., Friedman J. M. Positional cloning of the mouse obese gene and its human homologue. Nature. 1994 Dec 1;372(6505):425–432. doi: 10.1038/372425a0. [DOI] [PubMed] [Google Scholar]