Journal of Applied Physiology, Vol 73, Issue 3 801-805, Copyright © 1992 by American Physiological Society

ARTICLES

Effects of growth hormone on diaphragmatic recovery from malnutrition

J. K. Lanz Jr, M. Donahoe, R. M. Rogers and M. Ontell
Division of Pulmonary and Critical Care Medicine, University of Pittsburgh School of Medicine, Pennsylvania 15261.

A 25% weight loss was induced in adult Fisher 344 rats by nutritional deprivation. Subsequently, normal feeding was resumed. Refed animals were divided into three groups and received recombinant human growth hormone (rhGH) injections during 5 wk of refeeding, saline injections during 5 wk of refeeding, or 9 wk of refeeding without injections. The effects of nutritional deprivation and the various refeeding protocols on the cross-sectional areas (CSA) of each of the four types of myofibers [typed immunohistochemically with antibodies against four myosin heavy chain (MHC) isoforms known to be present in the rat diaphragm] were determined. Malnutrition decreased the CSA of myofibers containing MHC2X, MHC2B, and MHC2A (i.e., fast myofibers), with the greatest effect on muscle mass being due to the atrophy of fibers containing MHC2X. Fibers containing MHC beta/slow failed to undergo malnutrition-induced atrophy. Whereas refeeding for 5 wk in the absence of rhGH allowed the recovery of CSA of fibers containing MHC2A, fibers containing MHC2B and MHC2X remained smaller than fibers of similar type in control animals. In contrast, 5 wk of refeeding supplemented with rhGH returned all fiber CSAs to control values. Even when refeeding alone was extended to 9 wk to allow for weight stabilization, the CSA of the fibers containing MHC2B and MHC2X remained smaller than similar fibers in control muscle. Serum insulin-like growth factor, a marker of malnutrition (R. Reeves and J. Elders, J. Nutr. 109: 613-620, 1979), was significantly decreased after nutritional deprivation and returned to normal after 5 wk of refeeding and GH supplementation.

This article has been cited by other articles:

				B Polla, G D'Antona, R Bottinelli, and C Reggiani Respiratory muscle fibres: specialisation and plasticity Thorax, September 1, 2004; 59(9): 808 - 817. [Abstract] [Full Text] [PDF]

				F. Laghi and M. J. Tobin Disorders of the Respiratory Muscles Am. J. Respir. Crit. Care Med., July 1, 2003; 168(1): 10 - 48. [Abstract] [Full Text] [PDF]

				L. Yang, J. Luo, J. Bourdon, M.-C. Lin, S. B. Gottfried, and B. J. Petrof Controlled Mechanical Ventilation Leads to Remodeling of the Rat Diaphragm Am. J. Respir. Crit. Care Med., October 15, 2002; 166(8): 1135 - 1140. [Abstract] [Full Text] [PDF]

				B. T. Ameredes, J. F. Watchko, M. J. Daood, J. F. Rosas, M. P. Donahoe, and R. M. Rogers Growth Hormone Improves Body Mass Recovery with Refeeding after Chronic Undernutrition-Induced Muscle Atrophy in Aging Male Rats J. Nutr., December 1, 1999; 129(12): 2264 - 2270. [Abstract] [Full Text]

				B. T. Ameredes, J. F. Watchko, M. J. Daood, J. F. Rosas, M. P. Donahoe, and R. M. Rogers Growth hormone restores aged diaphragm myosin composition and performance after chronic undernutrition J Appl Physiol, October 1, 1999; 87(4): 1253 - 1259. [Abstract] [Full Text] [PDF]

				G. GAYAN-RAMIREZ, F. VANDERHOYDONC, G. VERHOEVEN, and M. DECRAMER Acute Treatment with Corticosteroids Decreases IGF-1 and IGF-2 Expression in the Rat Diaphragm and Gastrocnemius Am. J. Respir. Crit. Care Med., January 1, 1999; 159(1): 283 - 289. [Abstract] [Full Text]

				R. Bottinelli, M. Narici, M. A. Pellegrino, B. Kayser, M. Canepari, G. Faglia, and A. Sartorio Contractile Properties and Fiber Type Distribution of Quadriceps Muscles in Adults with Childhood-Onset Growth Hormone Deficiency J. Clin. Endocrinol. Metab., December 1, 1997; 82(12): 4133 - 4138. [Abstract] [Full Text] [PDF]

				M. I. Lewis, T. J. Lorusso, and M. Fournier Anabolic influences of insulin-like growth factor I and/or growth hormone on the diaphragm of young rats J Appl Physiol, June 1, 1997; 82(6): 1972 - 1978. [Abstract] [Full Text] [PDF]