Paulo Henrique Aleixo; Robson Chacon Castoldi; Henrique Izaias Marcelo; Francis Lopes Pacagnelli; Luiz Carlos Marques Vanderlei; José Carlos Silva Amargo Filho; Ines Cristina Giometti Ceda & William Dias Belangero

The objective of this study was to investigate the effects of growth hormone (GH) associated with a strength training (ST) protocol on body composition and muscle tissue in aged rats. Forty aged animals of the Wistar lineage were used, divided into 4 groups: Control (C) [n=10], GH Control (GHC) [n=10], Strength Training (T) [n=10], and Strength Training (n=10) with Growth Hormone (GHT) [n=10]. The intervention period was 4 weeks and consisted of 4 x 10 water jumps, performed 3 times a week, on non-consecutive days, with an overload of 50% of body mass. The GHC and GHT groups received 0.2 IU per kilogram of body mass (0.067 mg/kg) at the start of each training session. After the end of the experiment, the animals were euthanized with a combination of anesthetics and exsanguination. The variables Body Mass, Body Mass Index (BMI), and the Lee Index (Lee) were measured and visceral adipose tissue was collected. Furthermore, the medial gastrocnemius muscle was removed to measure the cross-sectional area. The Shapiro-Wilk normality test was performed. For the “body mass” variable, repeated measures ANOVA analysis of variance was used, with the Bonferroni post-test. For the BMI, Lee index, and visceral adipose tissue variables, analysis of variance ANOVA with Tukey's post-test was used. To analyze the “cross-sectional area”, the Kruskal-Wallis test with Dunn’s post-test was used. All procedures adopted a significance value of 5% (p<0.05). There were no statistically significant differences for the variables body mass, visceral adipose weight, BMI, and Lee index (p>0.05). Increases in muscle were observed in all experimental groups (p<0.05). It is concluded that GH caused hypertrophy in the muscle, with or without training, however, there were no differences in the body composition of aged animals.

KEY WORDS: Aging; Growth Hormone; Strength training; Skeletal muscle; Wistar Rats.

ALEIXO, P. H.; CHACON CASTOLDI, R.; MARCELO, H. I.; LOPES PACAGNELLI, F.; MARQUES VANDERLEI, L. C.; SILVA AMARGO FILHO, J. C.; GIOMETTI CEDA, I. C. & BELANGERO,W. D. Growth hormone (GH) and strength training: Effects on morphology of aged rats. Int. J. Morphol., 43(4):1133-1139, 2025.