Frank Frisch

Temporal effects of testosterone propionate injections on serum lipoprotein concentrations in rats.

UNLABELLED The chronic abuse of androgenic anabolic steroids, a group of synthetic derivatives of testosterone, to improve athletic performance have demonstrated compromised serum lipoprotein concentrations reflecting an elevated risk for cardiovascular disease. While the detrimental alterations in the lipoprotein profile have been reported consistently for orally administered androgenic anabolic steroids, the reports examining the effects of parenteral administration of testosterone upon the lipid profile remain equivocal. PURPOSE The purpose of this study was to determine whether compromised serum lipoprotein concentrations would be manifest in rats receiving testosterone injections (twice per week) over the time course of 7 wk. METHODS Male rats were randomly assigned to either an experimental group (dose per injection, 3 mg x kg(-1) testosterone propionate solubilized in 1 mL of safflower oil) or a control group (injected with an isovolumic amount of safflower oil alone). The effects of the steroid regimen on the serum lipoprotein profiles were followed after 1, 3, 5, and 7 wk of injections. To assess the relative effects of testosterone propionate, testicular mass was determined at the time of sacrifice. RESULTS Testicular mass (mean +/- SE) was significantly lower (P<0.01) in the experimental group, 3.08+/-0.03 g, compared with that in controls, 3.82+/-0.05 g, by week 3 and continued to decline for the remainder of the steroid regimen, reaching a nadir of 2.70+/-0.01 g at week 5. No significant differences were observed between groups for total serum cholesterol, serum triacylglycerols, or serum low density lipoprotein (LDL)-C at any time point. However, at week 7, serum high density lipoprotein (HDL)-C (mean +/- SE) was significantly lower (P<0.02) in the testosterone treated animals, 32+/-2 mg x dL(-1), compared with that in controls, 47+/-2 mg x dL(-1). As a result, the ratio of total cholesterol to HDL-C (mean +/- SE) significantly increased (P<0.02) by the seventh week in the testosterone treated group, 3.5+/-0.2, versus controls, 2.5+/-0.2. CONCLUSIONS The results suggest that while testosterone propionate injections elicit a reduction in testicular mass within 3 wk, the lipoprotein profile is not altered until week 7. Further, the only compromised parameter under the conditions of this study is the decrease in serum HDL-C.

Zumba® Fitness workouts: are they an appropriate alternative to running or cycling?

A sedentary lifestyle (i.e., physically inactive) has been associated with a variety of diseases such as: obesity, type II diabetes, and heart disease. Chronic aerobic exercise can be used as a prophylactic against these diseases. However, the challenges for individuals, prior to engaging in a training program for disease prevention, include the selection of an appropriate aerobic exercise as well as longterm compliance. Running or cycling is the traditional modes of aerobic exercise used to minimize the risk of disease and maintain a healthy body weight. In this regard, the American College of Sports Medicine recommends a caloric expenditure of 300 kcal per exercise session [1]. Numerous studies examining running and cycling have reported caloric expenditures well above 300 kcal per exercise session [4– 8]. Running and cycling have also been reported to elicit increases in plasma beta (b) endorphin levels [4–8, 12, 13]. b endorphin can be released by the pituitary gland in response to exercise of sufficient intensity and duration and has been associated with euphoria and exercise addiction in what has been referred to by the fitness community as ‘‘runner’s high’’ [2, 10]. An exercise-induced elevation in b endorphin would provide additional support for the efficacy of the aerobic activity (in the prevention of disease) by increasing the likelihood of long-term compliance. While running and cycling have been the traditional activities to engage in aerobic activity, fitness classes and home exercise DVDs have become an attractive alternative. In this regard, dance fitness DVDs, as employed by Zumba Fitness, have become extremely popular. Originating in Columbia, South America, Zumba Fitness was created as a Latin-inspired dance fitness program that combines various types of dance elements (e.g. hip-hop, samba, etc.) to music as a method to engage in aerobic exercise as an alternative to running or cycling. To date, only one study has specifically examined the efficacy of Zumba Fitness as an appropriate workout for health benefits. Luettgen et al. [9] used exercise heart rates to predict the oxygen consumption expended during a Zumba class that lasted an average of 39 min. Specifically, with use of an incremental treadmill test, they employed a linear regression equation between heart rate and oxygen consumption (VO2). Based upon a subject’s heart rate during a Zumba class, they estimated the oxygen consumption to determine caloric expenditure [9]. They reported an average exercise heart rate of 154 bpm (79 % of HR max) and an average caloric expenditure of 370 kcal per class [9] suggesting that a Zumba Fitness workout may be an appropriate alternative to running or cycling. Estimates of VO2 via exercise heart rates and the subsequent determination of caloric expenditure, as employed by Luettgen et al. [9], would seem appropriate given the difficulty in measuring VO2 during aerobic dance exercises. Given the differences in movements between running on a treadmill and dance, there may be limitations with the use of treadmill heart rates to predict VO2 during a dance workout. Currently, no one has actually measured oxygen consumption during dance exercises to substantiate the E. Sternlicht Department of Kinesiology, Occidental College, Los Angeles, CA 90041, USA

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

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.

Training suppresses hepatic lactate dehydrogenase activity without altering the isoenzyme profile

A decrease in hepatic lactate dehydrogenase (LDH) activity following endurance training has been a consistent observation. In the present study, we sought to determine whether the training-induced decrease in hepatic LDH activity (pyruvate = substrate) was associated with a shift in the isoenzyme profile and/or alteration in other kinetic parameters. Animals (rats) were randomly assigned to either an endurance trained group (running 90 min at 30 m.min-1, 10% grade) or sedentary control group. Eight weeks of endurance training resulted in a significant decrease in maximal hepatic LDH activity for the forward reaction (pyruvate-->lactate), 107.3 +/- 5.5 mumol.min-1.g-1, when compared with control animals, 147.3 +/- 5.6 mumol.min-1.g-1. A similar decrease was observed for maximal LDH activity in the reverse reaction (lactate-->pyruvate), 49.8 +/- 2.1 vs 66.7 +/- 2.9 mumol.min-1.g-1, trained and controls, respectively. Training was also observed to decrease the Km for the reverse reaction, 5.18 +/- 0.78 mM vs 6.94 +/- 0.55 mM, for trained and controls, respectively. Km for the forward reaction was unaffected by training. Gel electrophoresis with densitometric evaluation revealed no shift in the isoenzyme pattern following endurance training. LDH5 accounted for 89% +/- 2%, whereas 6% +/- 0.5% was observed in LDH4, and 4% +/- 0.3% was observed in LDH3 for both groups. The densitometric area was approximately 34% lower from trained liver homogenates, a fractional decrease similar to that observed for maximal LDH activity. The decrease in hepatic LDH activity with endurance training appears attributable to a down regulation of enzyme content, with no significant alteration in isoenzyme distribution.