Strength training does not alter the effects of testosterone propionate injections on high-density lipoprotein cholesterol concentrations.

Abstract

The purpose of the study was to examine the long-term effects of a high-volume strength training program (vertical ladder climbing) and testosterone propionate injections (intraperitoneal) on serum lipid and lipoprotein concentrations in male Sprague-Dawley rats. The animals were randomly divided into a testosterone (T)-treated group (dose per injection, 2.5 mg/kg testosterone propionate solubilized in 1 mL safflower oil) and a control (C) group (injected with an isovolumic amount of safflower oil alone). Animals were further divided into a strength-trained group (E) and a sedentary group (S). The 10-week resistance training program consisted of weights (100% of body mass) appended to the tail as the animal climbed an 85-cm ladder to volitional fatigue. Following 10 weeks of strength training and testosterone injections, body weight was not significantly different between the main effects of strength training exercise (TE + CE v TS + CS) and testosterone injections (TE + TS v CE + CS) or between groups. Testicular mass (mean +/- SE) was measured as a relative indicator of testosterone effects. Both TE and TS had significantly reduced testicular mass (2.56 +/- 0.04 and 2.38 +/- 0.03 g, respectively) compared with CE and CS (3.49 +/- 0.03 and 3.49 +/- 0.04 g, respectively). No significant differences were observed between groups for total serum cholesterol, serum triglycerides, or serum low-density lipoprotein cholesterol (LDL-C). In contrast, significant decreases in high-density lipoprotein cholesterol (HDL-C) were observed for both TE (26.7 +/- 1.6 mg/dL) and TS (27.5 +/- 1.3 mg/dL) compared with CE (48.7 +/- 2.9 mg/dL) and CS (43.5 +/- 2.6 mg/dL). As a result, the total cholesterol to HDL-C ratio was significantly greater for TS + TE (4.7 +/- 0.1) compared with CS + CE (2.9 +/- 0.2). These observations suggest that in animals, a 10-week program of high-volume strength training does not elicit any beneficial effect on the lipid or lipoprotein status, nor does it attenuate the altered lipoprotein profile induced by testosterone propionate injections.