Gene expression of IGF-1 in the ovaries of female Wistar rats submitted to growth hormone and exercises

Some people who seek a better physical performance often use the growth hormone (GH) indiscriminately. Studies have provided better knowledge about the effects of GH in reproduction. The GH acts directly or indirectly on the folliculogenesis and corpus luteum formation. However, until now, has not been investigated the frequent use of GH combined with physical exercises in the expression of genes that respond to GH in the gonads, as the insulin-like growth factor (IGF-1). The objective of this study was to verify the gene expression of IGF-1 in ovaries of female rats that were subjected to the use of GH associated or not to exercises, as an experimental model of human. For this aim, 40 rats were divided into 4 groups: CT (control group), GH (group with administration of 0.2 IU/kg of GH), Ex (group which was submitted to physical exercises for 4 sets of 10 vertical jumps in water with a weight of 50% of the animal's weight) and ExGH (group which was submitted to physical exercises and was administered GH). Vaginal cytology was performed daily and after 30 days all rats were anesthetized and induced to death by exsanguination in diestrus phase of estrous cycle. The RNA extraction of the ovaries was performed, followed by reverse transcription and quantitative analysis of gene expression of IGF-1. The analysis of IGF-1 was by real time PCR, using RPS-18 and HPRT-1 endogenous genes as a normalizing of reaction. The statistical analysis of the data of gene expression was performed by ANOVA and the comparisons of means by Tukey test (P 0.05). Despite the IGF-1 is synthesized by the liver, and the majority of organic cells, when stimulated by GH and physical exercise to stimulate an increase in the release of GH (GOMES et al, R Bras Ci Mov, 11:57-62, 2003), in the present study no difference was found in the gene expression of IGF-1 in the ovaries between the groups. We conclude that the GH and physical exercise under the conditions of this experiment do not alter the gene expression of IGF-1 in ovaries of female rats.