Differential Effect of Testosterone Supplements on Body Composition in Young and Old Male Spontaneously Hypertensive Rats

• Published in: The FASEB journal Vol. 31; no. S1
• Main Authors: Maranon, Rodrigo Oscar, Dalmasso, Carolina, Patil, Chetal N, Cardozo, Licy L Yanes, Juncos, Luis A, Reckelhoff, Jane F
• Format: Journal Article
• Language: English
• Published: 01-04-2017
• ISSN: 0892-6638; 1530-6860
• DOI: 10.1096/fasebj.31.1_supplement.850.1

Abstract only The use of testosterone supplements (T) is increasing in the US and is mainly used for conditions such as treatment of hypogonadism, to increase libido, strength, and physical resistance, and to prevent osteoporosis. While clinical and experimental evidence shows that T could improve metabolic parameters in obese men with hypogonadism, T could impair the cardiovascular system leading, for example, to elevated blood pressure. However, these data are controversial. Previously in our lab, we found that T increased blood pressure (BP) in young male spontaneously hypertensive rats (SHR), whereas in old male SHR, T had the opposite effect causing a decrease in BP. We had previously found that T improved metabolic syndrome and caused weight loss with an increase in activity in male obese Zucker rats. Whether T has an effect on body composition in young or old male SHR is unknown. In the present study, we tested the hypothesis that T in young (YSHR) and old (OSHR) male SHR changes body composition mainly by decreasing food intake and body weight. YSHR and OSHR were given testosterone propionate (22 mg/10 mm silastic pellet, sc) or placebo (empty pellets, sc), beginning at 16 weeks and 18 months of age for 6 weeks, respectively. T increased the plasma testosterone (RIA) by +2.5 fold in YSHR and +4 fold in OSHR (p<0.05). T increased plasma estradiol (RIA) by +2 fold in YSHR and 1 fold in OSHR (p<0.05). Tibia lengths were not affected by T in YSHR or OSHR. T reduced food intake in YSHR by 21% compared to YSHR+P (p<0.05), body weight by 8% (p<0.05), total water content by 19% (106±4 vs 87±6, p<0.05), and fat mass by 49% (4.9±0.6 vs 2.5±0.4 % BW, p<0.05), but had no effect on lean mass (p=NS) (all measured by ECHO MRI). Contrary to our hypothesis, while T modestly reduced FI by 12% in OSHR (26±1 vs 23±1 gr, p<0.05), there was no effect on BW, fat mass, total water content, or lean mass after 6 weeks of T supplementation. These data suggest that T supplements in young individuals can modulate body weight and FI and may contribute to an improvement in metabolic parameters. While not addressed in this study, the data also suggest that T supplementation needs to be reevaluated considering the risk for cardiovascular events in aging men who are overweight or obese.
Support or Funding Information
Supported by NIH‐R01HL66072, PO1HL51971 (JFR), 14POST18640015 (ROM), EFF Endocrine Res Grant (LLY).