Muscle Expressions of MGF, IGF-IEa, and Myostatin in Intact and Hypophysectomized Rats: Effects of rhGH and Testosterone Alone or Combined

A. E. Rigamonti; L. Locatelli; S. G. Cella; S. M. Bonomo; M. Giunta; F. Molinari; A. Sartorio; E. E. Müller

doi:10.1055/s-0028-1087205

Hormone and Metabolic Research, Table of Contents

Horm Metab Res 2009; 41(1): 23-29
DOI: 10.1055/s-0028-1087205

Original Basic

Muscle Expressions of MGF, IGF-IEa, and Myostatin in Intact and Hypophysectomized Rats: Effects of rhGH and Testosterone Alone or Combined

A. E. Rigamonti¹ , L. Locatelli¹ , S. G. Cella¹ , S. M. Bonomo¹ , M. Giunta¹ , F. Molinari¹ , A. Sartorio² , E. E. Müller¹

¹Department of Medical Pharmacology, University of Milan, Milan, Italy
²Laboratorio Sperimentale Ricerche Endocrinologiche (LSRE) e Divisione Malattie Metaboliche III, Istituto Auxologico Italiano, IRCCS, Milano e Piancavallo (VB), Italy

Abstract

Myostatin and mechano-growth factor (MGF), an isoform of insulin-like growth factor-I (IGF-I), are two important regulators of muscle hypertrophy. The aim of the present study was to investigate the effects of recombinant human growth hormone (rhGH) and/or testosterone on muscle MGF/IGF-IEa/myostatin expression in intact and hypophysectomized rats treated for 15 d with 1) saline or rhGH, 2) sesame oil or testosterone, 3) saline+sesame oil, or rhGH+testosterone (first experiment) or for 7 d with saline or rhGH (second experiment). Animals were killed by decapitation 24 h or 4 d after the last injection (first or second experiment, respectively). Muscle expressions of MGF, IGF-IEa, and myostatin were determined by RT-PCR. A significant increase in the weight of gastrocnemius muscle was observed only in hypophysectomized rats treated with rhGH alone or in combination with testosterone. Administration of rhGH to hypophysectomized rats caused a marked increase in both MGF and IGF-IEa muscle mRNA levels (without any change in the muscle expression of myostatin), an effect that was abolished when testosterone was combined with rhGH. Conversely, in intact rats rhGH increased myostatin muscle mRNA levels without affecting those of MGF and IGF-IEa. Testosterone, alone or combined with rhGH, induced an inhibition of myostatin expression in the muscle of intact rats, but did not change muscle paradigms of hypophysectomized rats. In conclusion, rhGH and/or testosterone anabolic effects in the muscle are mediated by a different expression of MGF/IGF-IEa/myostatin, which is related to the pituitary function.

Key words

MGF - IGF-IEa - myostatin - muscle - rhGH - testosterone

Full Text

References

1 Kraemer WJ, Ratamess NA. Hormonal responses and adaptations to resistance exercise and training. Sports Med. 2005; 35 339-361
2 Solomon AM, Bouloux PM. Modifying muscle mass – the endocrine perspective. J Endocrinol. 2006; 191 349-360
3 Lee SJ. Regulation of muscle mass by myostatin. Annu Rev Cell Dev Biol. 2004; 20 61-86
4 Goldspink G. Mechanical signals, IGF-I gene splicing, and muscle adaptation. Physiology (Bethesda). 2005; 20 232-238
5 Matsakas A, Diel P. The growth factor myostatin, a key regulator in skeletal muscle growth and homeostasis. Int J Sports Med. 2005; 26 83-89
6 MacPherron AC, Lawler AM, Lee SJ. Regulation of skeletal muscle mass in mice by a new TGF-beta superfamily member. Nature. 1997; 387 83-90
7 Grobet L, Martin LJ, Poncelet D, Pirottin D, Brouwers B, Riquet J, Schoeberlein A, Dunner S, Ménissier F, Massabanda J, Fries R, Hanset R, Georges M. A deletion in the bovine myostatin gene causes the double-muscled phenotype in cattle. Nat Genet. 1997; 17 71-74
8 Lin J, Arnold HB, Della-Fera MA, Azain MJ, Hartzell DL, Baile CA. Myostatin knockout in mice increases myogenesis and decreases adipogenesis. Biochem Biophys Res Commun. 2002; 291 701-706
9 Schuelke M, Wagner KR, Stolz LE, Hübner C, Riebel T, Kömen W, Braun T, Tobin JF, Lee SJ. Myostatin mutation associated with gross muscle hypertrophy in a child. N Engl J Med. 2004; 350 2682-2688
10 Tsuchida K, Sunada Y, Noji S, Murakami T, Uezumi A, Nakatani M. Inhibitors of the TGF-beta superfamily and their clinical applications. Mini Rev Med Chem. 2006; 6 1255-1261
11 Azzazy HM, Mansour MM, Christenson RH. Doping in the recombinant era: strategies and counterstrategies. Clin Biochem. 2005; 38 959-965
12 Philippou A, Maridaki M, Halapas A, Koutsilieris M. The role of the insulin-like growth factor 1 (IGF-1) in skeletal muscle physiology. In Vivo. 2007; 21 45-54
13 Olesen JL, Heinemeier KM, Haddad F, Langberg H, Flyvbjerg A, Kjaer M, Baldwin KM. Expression of insulin-like growth factor I, insulin-like growth factor binding proteins, and collagen mRNA in mechanically loaded plantaris tendon. J Appl Physiol. 2006; 101 183-188
14 Goldspink G. Gene expression in skeletal muscle. Biochem Soc Trans. 2002; 30 285-290
15 Hill M, Goldspink G. Expression and splicing of the insulin-like growth factor gene in rodent muscle is associated with muscle satellite (stem) cell activation following local tissue damage. J Physiol. 2003; 549 409-418
16 Cheema U, Brown R, Mudera V, Yang SY, MacGrouther G, Goldspink G. Mechanical signals and IGF-I gene splicing in vitro in relation to development of skeletal muscle. J Cell Physiol. 2005; 202 67-75
17 Goldspink G. Gene expression in muscle in response to exercise. J Muscle Res Cell Motil. 2003; 24 121-126
18 Diel P, Friedel A, Geyer H, Kamber M, Laudenbach-Leschowsky U, Schänzer W, Thevis M, Vollmer G, Zierau O. Characterisation of the pharmacological profile of desoxymethyltestosterone (Madol), a steroid misused for doping. Toxicol Lett. 2007; 169 64-71
19 Haisma HJ, Hon O de. Gene doping. Int J Sports Med. 2006; 27 257-266
20 Marcell TJ, Harman SM, Urban RJ, Metz DD, Rodgers BD, Blackman MR. Comparison of GH, IGF-I, and testosterone with mRNA of receptors and myostatin in skeletal muscle in older men. A J Physiol Endocrinol Metab. 2001; 281 E1159-E1164
21 Awede BL, Thissen JP, Lebacq J. Role of IGF-I and IGFBPs in the changes of mass and phenotype induced in rat soleus muscle by clenbuterol. A J Physiol Endocrinol Metab. 2002; 282 E31-E37
22 Brill KT, Weltman AL, Gentili A, Patrie JT, Fryburg DA, Hanks JB, Urban RJ, Veldhuis JD. Single and combined effects of growth hormone and testosterone administration on measures of body composition, physical performance, mood, sexual function, bone turnover, and muscle gene expression in healthy older men. J Clin Endocrinol Metab. 2002; 87 5649-5657
23 Liu W, Thomas SG, Asa SL, Gonzalez-Cadavid N, Bhasin S, Ezzat S. Myostatin is a skeletal muscle target of growth hormone anabolic action. J Clin Endocrinol Metab. 2003; 88 5490-5496
24 Scow RO, Hagan SN. Effect of testosterone propionate and growth hormone on growth and chemical composition of muscle and other tissues in hypophysectomized male rats. Endocrinology. 1965; 77 852-858
25 Rigamonti AE, Cella SG, Giordani C, Bonomo SM, Giunta M, Sartorio A, Muller E. Testosterone inhibition of growth hormone release stimulated by a growth hormone secretagogue: studies in the rat and dog. Neuroendocrinology. 2006; 84 115-122
26 Falconi G, Rossi GL. Transauricular hypophysectomy in rats and mice. Endocrinol. 1964; 74 301-303
27 Armstrong RB, Phelps RO. Muscle fiber type composition of the rat hindlimb. Am J Ana. 1984; 171 259-272
28 Mendler L, Zador E, Ver Heyen M, Dux L, Wuytack F. Myostatin levels in regenerating rat muscles and in myogenic cell cultures. J Muscle Res Cell Motil. 2000; 21 551-563
29 Torsello A, Bresciani E, Rossoni G, Avallone R, Tulipano G, Cocchi D, Bulgarelli I, Deghenghi R, Berti F, Locatelli V. Ghrelin plays a minor role in the physiological control of cardiac function in the rat. Endocrinology. 2003; 144 1787-1792
30 Iida K, Itoh E, Kim DS, del Rincon JP, Coschigano KT, Kopchick JJ, Thorner MO. Muscle mechano growth factor is preferentially induced by growth hormone in growth hormone-deficient lit/lit mice. J Physiol. 2004; 560 341-349
31 Nogami H, Watanabe T, Takeuchi T. Effect of growth hormone (GH) on the promotion of body weight gain in the spontaneous dwarf rat: a novel experimental model for isolated GH deficiency. Horm Metab Res. 1992; 24 300-301
32 Ferrante E, Giavoli C, Porretti S, Vassallo E, Ronchi CL, Lania AG, Beck-Peccoz P, Spada A. Evaluation of the components of the insulin-like growth factors system in GH-deficient adults: effects of twelve-month rhGH treatment. Horm Metab Res. 2006; 38 352-355
33 Hameed M, Lange KH, Andersen JL, Schjerling P, Kjaer M, Harridge SD, Goldspink G. The effect of recombinant human growth hormone and resistance training on IGF-I mRNA expression in the muscles of elderly men. J Physiol. 2004; 555 231-240
34 Frisch H. Growth hormone and body composition in athletes. J Endocrinol Invest. 1999; 22 ((5Suppl)) 106-109
35 Weber MM. Effects of growth hormone on skeletal muscle. Horm Res. 2002; 58 ((Suppl 3)) 43-48
36 Rennie MJ. Claims for the anabolic effects of growth hormone: a case of the emperor's new clothes?. Br J Sports Med. 2003; 37 100-105
37 Ehrnborg C, Ellegard L, Bosaeus I, Bengtsson BA, Rosen T. Supraphysiological growth hormone: less fat, more extracellular fluid but uncertain effects on muscles in healthy, active young adults. Clin Endocrinol (Oxf). 2005; 62 449-457
38 Rutherford OM, Jones DA, Round JM, Buchanan CR, Preece MA. Changes in skeletal muscle and body composition after discontinuation of growth hormone treatment in growth hormone deficient young adults. Clin Endocrinol (Oxf). 1991; 34 469-475
39 Kehely A, Bates PC, Frewer P, Birkett M, Blum WF, Mamessier P, Ezzat S, Ho KK, Lombardi G, Luger A, Marek J, Russell-Jones D, Sönksen P, Attanasio AF. Short-term safety and efficacy of human GH replacement therapy in 595 adults with GH deficiency: a comparison of two dosage algorithms. J Clin Endocrinol Metab. 2002; 87 1974-1979
40 Hill JJ, Davies MV, Pearson AA, Wang JH, Hewick RM, Wolfman NM, Qiu Y. The myostatin propeptide and the follistatin-related gene are inhibitory binding proteins of myostatin in normal serum. J Biol Chem. 2002; 277 40735-40741
41 Rigamonti AE, Cella SG, Marazzi N, Luigi L Di, Sartorio A, Muller EE. Growth hormone abuse: methods of detection. Trends Endocrinol Metab. 2005; 16 160-166
42 Hartgens F, Kuipers H. Effects of androgenic-anabolic steroids in athletes. Sports Med. 2004; 34 513-554
43 Handelsman DJ. Testosterone: use, misuse and abuse. Med J Aust. 2006; 185 436-439
44 Ma K, Mallidis C, Artaza J, Taylor W, Gonzalez-Cadavid N, Bhasin S. Characterization of 5′-regulatory region of human myostatin gene: regulation by dexamethasone in vitro. Am J Physiol Endocrinol Metab. 2001; 281 E1128-E1136
45 Mendler L, Baka Z, Kovacs-Simon A, Dux L. Androgens negatively regulate myostatin expression in an androgen-dependent skeletal muscle. Biochem Biophys Res Commun. 2007 14; 361 237-242
46 Rosen T. Supraphysiological doses of growth hormone: effects on muscles and collagen in healthy active young adults. Horm Res. 2006; 66 ((Suppl 1)) 98-104
47 Karila T, Koistinen H, Seppala M, Koistinen R, Seppala T. Growth hormone induced increase in serum IGFBP-3 level is reversed by anabolic steroids in substance abusing power athletes. Clin Endocrinol (Oxf). 1998; 49 459-463

Correspondence

Prof. E. E. Müller

Department of Medical Pharmacology

University of Milan

via Vanvitelli 32

20129 Milan

Italy

Phone: +39/02/503 170 10–170 12

Fax: +39/02/503 170 11

Email: eugenio.muller@unimi.it