**8. References**


atypical PKCζ isoform has been reported to modulate vascular responses (Damron *et al*., 1998, De Witt *et al*., 2001, Cogolludo *et al*., 2003) and neuronal NO release (Blanco-Rivero *et al*., 2005), we also tested the possible involvement of this isoform in endothelial NO release. The fact that PKCζ-PI decreased the basal and ACh-induced NO release showed the participation of this isoform. Moreover, since the three PKC inhibitors that we used, calphostin C, Gö6976 and PKCζ-PI, diminished both basal and ACh-induced NO release, it seems that eNOS, like nNOS (Blanco-Rivero *et al*., 2005), would have already been activated

These results show that PKC activity is enhanced in mesenteric arteries from orchidectomized rats, and this increase would be responsible for the higher nNOS and

Orchidectomy alters different cell signalling pathways that are involved in vascular tone regulation. Orchidectomy increases: (i) the formation of superoxide anion and peroxynitrite; (ii) the activity of PKC; and (iii) the expression of COX-2, the production of prostanoids derived from COX-2, as well as their vasoconstrictor effect. These aspects seem to be physiologically relevant, since the balance between vasodilator/vasoconstrictor prostanoids is lost in favour of vasoconstrictor substances in arteries from orchidectomized rats. This situation could indicate a disadvantage in cardiovascular function in the absence of male sex hormones, thereby suggesting that testosterone has a beneficial influence on the vasculature. However, in the animals used in our study (6 months old) several compensatory mechanisms are working: reactive oxygen species are able to induce relaxation; PKC positively regulates nNOS and eNOS activity ensuring the maintenance of NO release; the activity and expression of SOD are increased in an attempt to compensate for the increased superoxide anion production. This intriguing information makes it essential to perform studies in vascular function taking into account different cell signalling pathways that are working simultaneously. Future studies in the research field of androgens on cell signaling pathways are needed, since they will be of important interest to implement therapeutic

This work was supported by grant from Fondo de Investigaciones Sanitarias (PI08831).

generation of second messengers. *Pharmacol Rev* 38: 227-272.

cardiovascular system. *J Cell Physiol* 226:21-28.

adrenergic mechanisms. *Arch Int Pharmacodyn Ther* 250: 212-220.

Abdel-Latif A.A. (1986). Calcium mobilizing receptors, polyphosphoinositides, and the

Agostini M.C., Borda E.S., Gimeno M.F. *et al*. (1981). Differences in the effects of

Axelband F., Dias J., Ferrão F.M. *et al*. (2011). M. Nongenomic signaling pathways triggered

acetylcholine on the vas deferens from normal and castrated rats. A participation of

by thyroid hormones and their metabolite 3-iodothyronamine on the

by PKC in arteries from orchidectomized rats.

strategies that could improve vascular function.

**7. Acknowledgements** 

**8. References** 

eNOS activity.

**6. Conclusions** 


Androgens and Vascular Function 109

Félétou M. & Vanhoutte P.M. (2006). Endothelial dysfunction: a multifaceted disorder. *Am J* 

Ferrer M., Alonso M.J., Salaices M. *et al*. (2000). Increase in neurogenic nitric oxide

Ferrer M., Alonso M.J., Salaices M. *et al*. (2001). Angiotensin II increases neurogenic nitric

Ferrer M., Encabo A., Conde M.V. et al. (1995). Heterogeneity of endothelium-dependent

Ferrer M., Marín J. & Balfagón G. (2000). Diabetes alters neuronal nitric oxide release from

FitzGerald G.A. (1991). Mechanisms of platelet activation: thromboxane A2 as an amplifying

FitzGerald G.A., Healy C. & Daugherty J. (1987). Thromboxane A2 biosynthesis in human

Fleming I., Fisslthaler B., Dimmeler S. *et al*. (2001). Phosphorylation of Thr(495) regulates

Förstermann U., Pollock J.S., Schmint H.H.H.W. *et al.* (1991). Calmodulin-dependent

Frein D., Schildknecht S., Bachschmid M. *et al*. (2005). Redox regulation: a new challenge for

Furchgott R.F. & Zawadzki J.V. (1980). The obligatory role of endothelial cells in the relaxation of arterial smooth muscle by acetylcholine. *Nature* 288: 373-376. Gluais P., Lonchampt M., Morrow J.D. *et al*. (2005). Acetylcholine-induced endothelium-

Gonzales R.J., Ghaffari A.A., Duckles S.P. *et al*. (2005). Testosterone treatment increases

Gonzales R.J., Krause D.N. & Duckles S.P. (2004). Testosterone suppresses endotheliumdependent dilation of rat middle cerebral arteries. *Am J Physiol* 286: H552-H560. Greenberg S., George W.R., Kadowitz P.J. *et al*. (1974). Androgen-induced enhancement of

Gryglewski R.J., Palmer R.M.J. & Moncada S. (1986). Superoxide anion is involved in the breakdown of endothelium-derived vascular relaxing factor. *Nature* 320: 454-456. Guan X.B. & Dluzen D. (1991). Castration reduces potassium-stimulated norepinephrine release from superfused olfactory bulbs of male rats. *Brain Res* 568: 147-151.

rat mesenteric arteries. Role of protein kinase C. *Life Sci.* 66:337-345. Ferrer M., Tejera N., Marín J. *et al*. (1999). Androgen deprivation facilitates acetylcholineinduced relaxation by superoxide anion generation. *Clin Sci* 140: 1861-1868. Ferrer M., Salaices M. & Balfagón G. (2004). Endogenous prostacyclin increases neuronal

mechanisms in different rabbit arteries. *J Vasc Res* 32: 339-46.

signal for other agonists. *Am J Cardiol* 68: 11-15.

pharmacology. *Biochem Pharmacol* 70:811-823.

vascular reactivity. *Can J Physiol Pharmacol* 52: 14-22.

metabolism by endothelin-1 in mesenteric arteries from hypertensive rats. *J* 

oxide metabolism in mesenteric arteries from hypertensive rats. *Life Sci* 68: 1169-

nitric oxide release in mesenteric artery from spontaneously hypertensive rats. *Eur J* 

Ca(2+)/calmodulin-dependent endothelial nitric oxide synthase activity. *Circ Res*

endothelium-derivaded relaxing factor/nitric oxide synthase activity is present in the particulate and cytosolic fractions of bovine aortic endothelium cells. *Proc Nat* 

dependent contractions in the SHR aorta: the Janus face of prostacyclin. *Br J* 

thromboxane function in rat cerebral arteries. *Am J Physiol Heart Circ Physiol* 289:

*Physiol Heart Circ Physiol* 291: 985-1002.

*Cardiovasc Pharmacol* 36: 541-547.

*Pharmacol* 506: 151-156.

disease. *Fed Proc* 46:154-8.

*Acad Sci* 88: 1788-1792.

*Pharmacol* 146: 834-45.

578-85.

88: E68-75.

1179.


Braga-Basaria M., Dobs A.S., Muller D.C. *et al*. (2006). Metabolic syndrome in men with

Bredt D.S., Ferris C.D. & Snyder S.H. (1992). Nitric oxide synthase regulatory sites.

Calderone V., Baragatti B., Breschi M.C. *et al*. (2002). Hormonal influence on the release of

Caughey G.E., Cleland L.G., Gamble J.R. & James M.J. (2001) Up-regulation of endothelial

Ceballos G., Figueroa L., Rubio I. *et al*. (1999). Acute and nongenomic effect of testosterone

Chatrath R., Ronningen K.L., Severson S.R. *et al*. (2003). Endothelium-dependent responses

Chen D.C., Duckles S.P. & Krause D.N. (1999). Postjunctional α2-adrenoceptors in the rat tail

Chen G.X. (2003). Selective protein kinase C inhibitors and their applications. *Curr Drug* 

Cheng Y., Austin S.C., Rocca B. *et al*. (2002). Role of prostacyclin in the cardiovascular

Chodak G.W., Keane T. & Klotz L. (2002) Critical evaluation of hormonal therapy for

Cogolludo A., Moreno L., Bosca L. *et al*. (2003). Thromboxane α2-induced inhibition of

Damron D.S., Nadim H.S., Hong S.J. *et al*. (1998). Intracellular translocation of PKC isoforms

Davies S.P., Reddy H., Caivano M. & Cohen P. (2000). Specificity and mechanism of action of some commonly used protein kinase inhibitors. *Biochem J* 351:95-105. Dawson T.M., Steiner J.P., Dawson V.L. *et al*. (1993). Inmunosuppressant FK506 enhances

De Witt B.J., Kaye A., Ibrahim I.N. *et al*. (2001). Effects of PKC isozyme inhibitors on

Duckles S.P. & Miller V.M. (2010). Hormonal modulation of endothelial NO production. *Eur* 

Félétou M., Köhler R. & Vanhoutte P.M. (2010). Endothelium-derived vasoactive factors and

voltage-gated K+ channels and pulmonary vasoconstriction: role of protein kinase

in canine pulmonary artery smooth muscle cells by ANG II. *Am J Physiol* 274: L278-

phosphorylation of nitric oxide synthase and protects against glutamate

constrictor responses in the feline pulmonary vascular bed. *Am J Physiol* 280: L50-

hypertension: possible roles in pathogenesis and as treatment targets. *Curr* 

on isolate and perfused rat heart. *J Cardiovasc Pharmacol* 33: 691-697.

artery: effect of sex and castration. *Eur J Pharmacol* 372: 247-252.

24: 3979-3983.

H1168-1176.

288.

57.

sites. *J Biol Chem* 267: 10976-10981.

*Biol Chem* 276: 37839-37845.

Czeta. *Circ Res* 93: 656-63.

*J Physiol* 459: 841-851.

*Hypertens Rep* 12: 267-275.

noradrenaline. *J Pharm Pharmacol* 54: 523-528.

*Targets Cardiovasc Haematol Disord* 3: 301-307.

carcinoma of the prostate. *Urology* 60: 201-208.

neurotoxicity. *Proc Natl Acad Sci* 90: 9808-9812.

response to thromboxane A2. Science 296 539-541.

prostate cancer undergoing long-term androgen-deprivation therapy. *J Clin Oncol* 

Phosphorylation by cyclic AMP-dependent protein kinase, protein kinase C and calcium/calmodulin protein kinase; identification of flavin and calmodulin binding

endothelial nitric oxide: gender related dimorphic sensitivity of rat aorta for

cyclooxygenase-2 and prostanoid synthesis by platelets. Role of thromboxane A2. *J* 

in coronary arteries are changed with puberty in male pigs. *Am J Physiol* 285:


Androgens and Vascular Function 111

Liu D. & Dillon J.S. (2002). Dehydroepiandrosterone activates endothelial cell nitric-oxide

Martín M.C., Balfagón G., Minoves N. & Ferrer M. (2005). Androgen deprivation increases

Martiny-Baron G., Kazanietz M.G., Mischak H. *et al*. (1993). Selective inhibition of protein kinase C isozymes by the indolocarbazole Gö6976. *J Biol Chem* 268:9194-7. McNeill A.M., Kim N., Duckles S.P. *et al*. (1999). Chronic estrogen treatment increases levels

Minoves N., Balfagón G. & Ferrer M. (2002). Role of female sex hormones in neuronal nitric oxide release and metabolism in rat mesenteric arteries. *Clin Sci* 103: 239-247. Mukherjee S., Coaxum S.D., Maleque M. *et al*. (2001). Effects of oxidized low density

Munzel T., Heitzer T. & Harrison D.G. (1997). The physiology and pathophysiology of the

Murad F. (1997). What are the molecular mechanisms for the antiproliferative effects of nitric oxide and cGMP in vascular smooth muscle? *Circulation* 95: 1101-1103. Muzykantov V.R. (2001). Targeting of superoxide dismutase and catalase to vascular

Miyamoto A., Hashiguchi. Y, Obi T. *et al*. (2007). Ibuprofen or ozagrel increases NO release

Nakane M., Mitchell J., Forstermann U. & Murad F. (1991). Phosphorylation by calcium

Newton AC. (1995). Protein kinase C: structure, function and regulation. *J Biol Chem* 270:

Nielsen K.C. & Owman C. (1971). Contractile response and amine receptor mechanism in

Nishihara M., Yokotani K., Inoue S. & Osumi Y. (2000). U-46619, a selective thromboxane A2

Nishizuka Y. (1992). Intracellular signaling by hydrolysis of phospholipids and activation of

Nishizuka Y. (1984). The role of protein kinase C in cell surface signal transduction and

Nguyen Dinh Cat A & Touyz RM. (2011) Cell Signaling of Angiotensin II on Vascular Tone:

mimetic, inhibits the release of endogenous noradrenaline from the rat

isolated middle cerebral artery of the cat. *Brain Res* 27: 25-32.

hippocampus in vitro. *Jpn J Pharmacol* 82: 226-231.

Novel Mechanisms. *Curr Hypertens Rep* 13:122-128.

and l-nitro arginine induces TXA(2) release from cultured porcine basilar arterial

calmodulin-dependent protein kinase II and protein kinase C modulates the activity of nitric oxide synthase. *Biochem Biophys Res Commun* 180: 1396-1402. Namgaladze D., Shcherbyna I., Kienhofer J. *et al*. (2005). Superoxide targets calcineurin signaling in vascular endothelium. *Biochem BiophysRes Commun* 334: 1061-1067. Narumiya S., Sugimoto Y. & Ushikubi F. (1999). Prostanoid receptors: structures, properties,

arteries. *Nitric Oxide: Biology and Chemistry* 12: 163-176.

endothelial cells. *Cell Mol Biol* 47: 1051-1058.

endothelium. *J Controlled Release* 71: 1-21.

endothelial cells. *Vasc Pharmacol* 46. 85-90.

and functions. *Physiol Rev* 79:1193-226.

tumour promotion. *Nature* 308: 693-698.

28495-28498.

PKC. *Science* 258: 607-614.

nitric oxide/superoxide system. *Herz* 22:158-172.

*Chem* 277 :21379-21388.

2186-2190.

synthase by a specific plasma membrane receptor coupled to G alpha (i2,3), *J Biol* 

neuronal nitric oxide metabolism and its vasodilator effect in rat mesenteric

of endothelial nitric oxide synthase protein in rat cerebral microvessels. *Stroke* 30:

lipoprotein on nitric oxide synthetase and protein kinase C activities in bovine

Harrison D.G. (1994). Endothelial dysfunction in atherosclerosis. *Basic Res Cardiol* 89: 87-102.


Harrison D.G. (1994). Endothelial dysfunction in atherosclerosis. *Basic Res Cardiol* 89: 87-102. Henrion D., Dechaux E., Dowell F.J. *et al*. (1994). Alteration of flow-induced dilatation in

Holmquist F., Persson K., Bodker A. *et al*. (1994). Some pre- and postjunctional effects of castration in rabbit isolated corpus cavernosum and urethra. *J Urol* 152: 1011-1016. Hutchison S.J., Sudhir K., Chou T.M. *et al*. (1997). Testosterone worsens endothelial

Ishikawa M. & Quock R.M. (2003). Role of nitric-oxide synthase isoforms in nitrous oxide

Jones R.D., Jones H.T. & Channer K.S. (2004). The influence of testosterone upon vascular

Jones T.H. (2010). Testosterone deficiency: a risk factor for cardiovascular disease? *Trends* 

Jones T.H. & Saad F. (2009). The effects of testorene on risk factors for, and the mediators of,

Kapoor D., Malkin C.J. Channer K.S. *et al*. (2005). Androgens, insulin resistance and vascular

Kanashiro C.A. & Khalil R.A. (2001). Gender-related distinctions in protein kinase C activity

Kawasaki H., Takasaki K., Saito A. *et al*. (1988). Calcitonin gene-related peptide acts as a

Keating N.L., O'Malley A.J. & Smith M.R. (2006). Diabetes and cardiovascular disease

Khalil R.A. & van Breemen C. (1988). Sustained contraction of vascular smooth muscle: calcium influx or C-kinase activation?. *J Pharmacol Exp Ther* 244: 537-542. Kim E.J., Raval A.P. & Perez-Pinzon M.A. (2008). Preconditioning mediated by sublethal

Klein T., Eltze M., Grebe T. *et al*. (2007). Celecoxib dilates guinea-pig coronaries and aortic

Kobayashi E., Nakano H., Morimoto & Tamaoki T. (1989). Calphostin C (UCN-1028C), a

Kobayashi S., Inoue N., Azumi H. *et al*. (2002). Expressional change of the vascular

Li Y.J. Duckles& S.P. (1992). Effect of endothelium on the actions of sympathetic and sensory

Lincoln T.M., Dey N. & Sellak H. (2001). cGMP-dependent protein kinase signaling

nerves in the perfused rat mesentery. *Eur J Pharmacol* 210: 23-40.

novel vasodilator neurotransmitter in mesenteric resistance vessels of the rat.

during androgen deprivation therapy for prostate cancer. *J Clin Oncol* 24: 4448-4456.

oxygen-glucose deprivation-induced cyclooxygenase-2 expression via the signal transducers and activators of transcription 3 phosphorylation. *J Cereb Blood Flow* 

rings and amplifies NO/cGMP signaling by PDE5 inhibition. *Cardiovasc Res* 75: 390-

novel microbial compound is a highly potent and specific inhibitor of protein

antioxidant system in atherosclerotic coronary arteries. *Arterioscler Thromb Vasc Biol*

mechanisms in smooth muscle: from the regulation of tone to gene expression. *J* 

with induction of cyclo-oxygenase-2. *Br J Pharmacol* 121:83-90

smoke exposure in male rabbit aorta. *J Am Coll Cardiol* 29: 800-807.

antinociception in mice. *J Pharmacol Exp Ther* 306: 484-489.

the atherosclerotic process. *Atherosclerosis* 207: 318-327.

in rat vascular smooth muscle. *Am J Physiol* 280: C34-C45.

kinase C. *Biochem Biophys Res Commun* 159: 548-553.

reactivity. *Eur J Endocrinol* 151: 29-37.

disease in men. *Clin Endocrinol* 63: 239-250.

*Endocrinol Metab* 21: 496-503.

*Nature* 335: 164-167.

*Metab* 28: 1329-1340.

397.

9: 184-190.

*Appl Physiol* 91: 1421-1430.

mesenteric resistance arteries of L-NAME treated rats and its partial association

dysfunction associated with hypercholesterolemia and environmental tobacco


Androgens and Vascular Function 113

Simoncini T., Mannella P., Fornari L. *et al*. (2003). Dehydroepiandrosterone modulates

Singh .R, Pervin S., Shryne J. *et al*. (2000). Castration increases and androgens decrease nitric

Smith M.R., Finkelstein J.S., McGovern F.J. *et al*. (2002). Changes in body composition during

Spitaler M. & Cantrell D.A. (2004). Protein kinase C and beyond. *Nature Immunol* 5:785-790. Strehlow K., Rotter S., Wassmann S. *et al*. (2003). Modulation of antioxidant enzyme

Sun C., Chen M., Mao J. *et al*. (2001). Biphasic effects of orchidectomy on calcitonin gene-

Szmydynger-Chodobska J., Zink B.J. & Chodobski A. (2011) Multiple sites of vasopressin

Tanaka M., Umemoto S., Kawahara S. *et al*. (2005). Angiotensin II type 1 receptor antagonist

Teoh H., Quan A. & Man R.Y. (2000). Acute impairment of relaxation by low levels of testosterone in porcine coronary arteries. *CardiovascRes* 45: 1010-1018. Tep-areenan P., Kendall D.A. & Randal M.D. (2003). Mechanisms of vasorelaxation to

Tesauro M., Schinzari F., Caramanti M. *et al*. (2010). Cardiovascular and metabolic effects of

Toda N. & Okamura T. (2003). The pharmacology of nitric oxide in the peripheral nervous

Tracey W.R., Nakane M., Basha F. *et al*. (1995). In vivo pharmacological evaluation of two

Traish A.M. & Kypreos K.E. (2011). Testosterone and cardiovascular disease: an old idea

Vanhoutte P.M. (1996). Endothelium-dependent responses in congestive heart failure. *J Mol* 

Villablanca A.C., Jayachandran M. & Banka C. (2010). Atherosclerosis and sex hormones:

Ward J.P.T., Knock G.A., Snetkov V.A. & Aaronson P.I. (2004). Protein kinases in vascular

Wei E.P., Kontos H.A. & Beckman J.S. (1996). Mechanisms of cerebral vasodilation by

Weiner I., Lizasoain S.A., Baylis R.G. *et al*. (1994). Induction of calcium-dependent nitric

Wolin M.S. (2002). Interaction of oxidants with vascular signaling system. *Arterioscler* 

oxide synthases by sex hormones. *Proc Natl Acad Sci* 91: 5212-5216.

smooth muscle tone -role in the pulmonary vasculature and hypoxic pulmonary

superoxide, hydrogen peroxide, and peroxynitrite. *Am J. Physiol* 271: H1262-H1266.

with modern clinical implications. *Atherosclerosis* 214:244-248.

novel type II (inducible) nitric oxide synthase inhibitors. *Can J Physiol Pharmacol* 73:

and angiotensin-converting enzyme inhibitor altered the activation of Cu/Zncontaining superoxide dismutase in the heart of stroke-prone spontaneously

expression and function by estrogen. *Circ Res* 93: 170-177.

testosterone in the rat aorta. *Eur J Pharmacol* 465: 125-132.

system of blood vessels. *Pharmacol Rev* 55:271-324.

hypertensive rats. *Hypertens Res* 28: 67-77.

ghrelin. *Curr Diabetes Rev* 6:228-35.

*Cell Cardiol* 28: 2233-2240.

current concepts. *Clin Sci* 119:493-513.

*Thromb Vasc Biol* 20: 1430-1442.

vasoconstriction. *Pharmacol Ther* 104: 207-231.

related peptide synthesis and release. *Neuroreport* 12: 3497-3502.

synthesis in the injured brain. *J Cereb Blood Flow Metab* 31:47-51.

*Endocrinology* 144: 3449-55.

3672-7.

603.

665-669.

endotelial nitric oxide synthesis via direct genomic and nongenomic mechanisms.

oxide synthase activity in the brain: physiologic implications. *Proc Natl Acad Sci* 97:

androgen deprivation therapy for prostate cancer. *J Clin Endocrinol Metab* 87: 599-


Noll G. & Luscher T.F. (1998). The endothelium in acute coronary syndromes. *Eur Heart J* 19:

Oeckler R.A. & Wolin M.S. (2000). New concepts in vascular nitric oxide signalling. *Curr* 

Okada D. (1992). Two pathways of cyclic GMP production through glutamate receptor-

Okada D. (1995). Protein kinase C modulates calcium sensitivity of nitric oxide synthase in

Onoue S., Endo K., Yajima T. *et al*. (2002). Pituitary adenylate cyclase activating polypeptide regulates the basal production of nitric oxide in PC12 cells. *Life Sci* 71: 205-214. Orshal J.M. & Khalil R.A. (2004). Gender, sex hormones and vascular tone. *Am J Physiol* 286:

Oury T.D., Day B.J. & Crapo J.D. (1996). Extracellular superoxide dismutase: a regulator of

Polytarchou C. & Papadimitriou E. (2005). Antioxidans inhibit human endothelial cell

Price D.T., Vita J.A. & Keaney J.F.Jr. (2000). Redox control of vascular nitric oxide

Rapoport R.M. & Williams S.P. (1996). Role of prostaglandins in acetylcholine-induced

Reynoso R., Mohn C., Retory V. *et al*. (2002). Changes in the effect of testosterone on

Rubanyi G.M. & Vanhoutte P.M. (1986). Oxygen-derived free radicals, endothelium, and responsiveness of vascular smooth muscle. *Am J Physiol* 120: H815-H821. Rump L.C. & Schollmeyer P. (1989). Effects of endogenous and synthetic prostanoids, the

Saad F., Gooren L.J., Haider A. *et al*. (2008). A dose-response study of testosterone on sexual

Scordalakes E.M., Imwalle D.B. & Rissman E.F. (2002). Oestrogen's masculine side: medition

Shang Y. & Dluzen D.E. (2002). Castration increases nisoxetine-evoked norepinephrine levels in vivo within the olfactory bulb of male rats. *Neurosci Lett* 328: 81-84. Shanmugam N., Gaw-Gonzalo I.T. & Natarajam R. (2004). Molecular mechanisms of high glucose-induced cyclooxygenase-2 expression in monocytes. *Diabetes* 53: 795-802. Siddiqui A. & Shah B.H. (1997). Neonatal androgen manipulation differentially affects the

Simon D., Charles M.A., Nahoul K. *et al*., (1997). Association between plasma testosterone

functions through down-regulation of endothelial nitric oxide synthase activity.

contraction of aorta from spontaneously hypertensive and Wistar-Kyoto rats.

hypothalamic nitric oxide synthetase during sexual maturation. Its relationship

thromboxane A2 receptor agonist U-46619 and arachidonic acid on [3H] noradrenaline release and vascular tone in rat isolated kidney. *Br J Pharmacol* 97:

dysfunction and features of the metabolic syndrome using testosterone gel and

development of monoamine systems in rat cerebral cortex, amygdale and

and cardiovascular risk factors in healthy adult men: the telecom study. *J Clin* 

mediated nitric oxide synthesis. *J Neurochem* 59: 1203-1210.

nitric oxide bioavailability. *Laboratory Investigation* 75: 617-36.

bioavailability. *Antioxidants & Redox Signaling* 2: 919-935.

parenteral testosterone undecanoate. *J Androl* 29: 102-105.

of mating in male mice. *Reproduction* 124: 331-338.

hypothalamus. *Dev Brain Res* 98: 247-252.

*Endocrinol Metab* 82: 682-689.

with GnRH release. *Neuroendocrinol Lett* 23: 101-4.

cerebellar slices. *J Neurochem* 64: 1298-1304.

C30-C38.

R233-R249.

*Atheroscler* 2: 437-444.

*Eur J Pharmacol* 510: 1-38.

*Hypertension* 28: 64-75.

819-828.


**7** 

*France* 

**Orchidectomy Upregulates While Testosterone** 

Ornithine aminotransferase (L-ornithine: 2-oxoacid aminotransferase, OAT, EC 2.6.1.13) plays crucial physiological roles in amino acid metabolism because this enzyme is at the crossroad of several pathways including those of L-arginine, L-ornithine, L-glutamate, Lglutamine, and L-proline. Specifically, OAT catalyzes the transamination of L-ornithine in the presence of α-ketoglutarate to produce one molecule of L-glutamate and the unstable compound glutamate-γ-semialdehyde that is spontaneously converted into Δ1-pyrroline-5 carboxylate. This latter molecule is further metabolized by the enzyme pyrroline-5 carboxylate dehydrogenase into a second molecule of L-glutamate (Wakabayashi, 2004). The enzyme is expressed in many mammalian tissues including the liver, the kidney, and the intestine which exhibit the highest OAT activities (Peraino & Pitot, 1963; Herzfeld & Knox, 1968; Sanada et al., 1970; Kasahara et al., 1986; Alonso & Rubio, 1989; Levillain et al., 2007; Ventura et al., 2009). These enzymes may not only display diverse tissue-specific physiological roles, but demonstrate marked sexual differences in expression and activity. In rat kidneys, estrogen dramatically increased the expression of OAT and is responsible for the higher levels of OAT in female than in male rat kidney (Herzfeld & Knox, 1968; Lyons & Pitot, 1977; Mueckler & Pitot, 1983; Mueckler et al., 1984; Levillain et al., 2004). The presence of thyroid hormone is required for estrogen induction. These hormones exert a synergistic effect on the expression of OAT gene (Mueckler & Pitot, 1983). The expression of OAT gene during the rat postnatal development strongly supports the sexual dimorphism of OAT in kidney, but not in liver (Herzfeld & Knox, 1968; Herzfeld & Greengard, 1969). Taken together, the expression of OAT gene in the female rat kidney is naturally upregulated in

The expression of OAT gene in the mouse kidney has been reported by different authors who independently measured OAT mRNA and protein levels or OAT activity (Alonso & Rubio, 1989; Natesan & Reddy, 2001; Yu et al., 2003; Levillain et al., 2005; Manteuffel-Cymborowska et al., 2005; Levillain et al., 2007; Ventura et al., 2009). Strong evidences

**1. Introduction** 

the presence of estrogen.

**Treatment Downregulates the Expression of** 

**Ornithine Aminotransferase Gene** 

**in the Mouse Kidney** 

Olivier Levillain, Cyril Dégletagne,

Dominique Letexier and Henri Déchaud1 *University Claude Bernard Lyon 1, UMR 5123 CNRS 1University Claude Bernard Lyon 1, U1060 INSERM* 

