The metabolic and endocrine effects of anabolic compounds, viz., Zeranol, diethylstilbestrol (DES) and Synovex-S were investigated in growing steers in order to understand their biochemical mechanisms of action. The growth promoting properties of certain anabolic compounds were established. A marked reduction in the plasma concentration of urea nitrogen, alpha amino nitrogen and amino acids was found in steers implanted with anabolic compounds. The results suggested that anabolic compounds significantly alter the nitrogen metabolism of steers by increasing the efficiency of utilization of absorbed nitrogenous compounds. Implantations of DES and Synovex-S were more effective than Zeranol in enhancing the growth rate and altering the nitrogen metabolism of the animals. The usefulness of measuring NT-methylhistidine in urine as a non-destructive, in vivo index of myofibrillar protein degradation and the developmental aspects of muscle protein metabolism in cattle were demonstrated. The implantation of anabolic compounds, in general, increased the efficiency of muscle protein synthesized and protein deposited by the steers. Implantations of DES and Synovex-S were more effective than Zeranol due to a reduction in the muscle protein degradation per unit synthesized. Hydroxyproline excretion in the urine was used as an in vivo indicator of collagen turnover in steers. As the animals gained weight and advanced in maturity, its excretion in the urine decreased indicating a reduction in collagen turnover. Implantation of DES increased the hydroxyproline excreted by steers, while, Zeranol and Synovex-S had very little effect. These results indicate that DES implantation increases the amount of collagen and its turnover in steers. DES and Synovex-S exerted a significant influence on the activity of the thyroid gland and caused an elevation in the circulating concentrations of free and total thyroxine. On the other hand, the implantation of Zeranol resulted in plasma thyroxine concentrations similar to or lower than in the controls. Plasma triiodothyronine concentrations were not influenced by any of the compounds studied. Increased plasma thyroxine concentration observed in the DES or Synovex-S implanted steers was shown to be due to an increase in the secretion and a decrease in the metabolic clearance rates of thyroxine. The implantation of Zeranol appeared to increase the secretion rate of thyroxine, and resulted in slightly depressed plasma thyroxine concentration due to a higher metabolic clearance rate. Implantations of anabolic compounds resulted in an increase in the circulating concentration of growth hormone. Implantations of DES and Synovex-S were more effective than Zeranol in increasing the plasma growth hormone concentration. The kinetic parameters of growth hormone metabolism in growing steers were determined. The anabolic compounds increased the secretion rate of growth hormone from the pituitary gland suggesting that these compounds evoke growth promotion in steers through changes in the endogenous growth hormone status. These changes involved an increased secretion rate of growth hormone with very little alteration in the metabolic clearance rate. The metabolism of insulin was influenced to a significant extent in steers implanted with anabolic compounds. Zeranol increased the insulin secretion rate to a greater extent than Synovex-S or DES. The data indicated that the implantation of anabolic compounds altered the metabolism of steers significantly and enhanced the secretion rate of thyroxine, growth hormone and insulin. They altered the metabolism of the steers in such a way that there was an efficient utilization of absorbed nutrients. The mechanisms of action of anabolic compounds have been discussed in detail and the directions for future research suggested. / Land and Food Systems, Faculty of / Graduate

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.

Thesis (M.S. in psychology)--Washington State University, May 2010. / Title from PDF title page (viewed on May 3, 2010). "Department of Psychology." Includes bibliographical references (p. 32-43).

A series of six experiments was conducted on female cattle and guinea-pigs to investigate the effects of some anabolic compounds on both growth and reproductive functions in the two species. The results indicate that trenbolone acetate increased significantly, the live-weight gains of heifers and improved the efficiency of food conversion. Zeranol and oestradiol-17 treatments had no effect on growth performance. Trenbolone acetate inhibited or delayed ovulation and resulted in elevation of plasma oestradiol-17 concentrations. Zeranol and oestradiol-17 had no effect on estrous cycle occurrence nor ovulation as determined by plasma progesterone concentrations. It is concluded from studies investigating the response to gonadotrophin releasing hormone (Gn-RH), oestradiol benzoate (OE2-B) and pregnant mares' serum gonadotrophins (PMSG) that trenbolone acetate acts (1) on the pituitary gland to decrease the sensitivity to Gn-RH, (2) on the ovary to decrease the sensitivity of the ovarian follicles to gonadotrophins and (3) acts on the pituitary gland and/or the hypothalamus to block the positive feedback effect of oestrogen to release the LH-surge. In the guinea-pig, trenbolone acetate at dose levels of 2 and 10 mg/kg body-weight inhibited ovulation. At a dose level of 0.4 mg/kg body weight, trenbolone acetate prolonged the length of the oestrous cycle. When trenbolone and testosterone, at dose levels of 3.1 and 15.7 mmol/l each, were compared, trenbolone was shown to have more general promoting activity than testosterone. The high dose of both hormones inhibited ovulation and increased the rate of occurrence of atretic follicles. However, only testosterone at the higher dose decreased the weight of the ovaries and lowered the number of follicles. From studies measuring the response to follicles stimulating hormone (FSH) and human chorionic gonadotrophin (HCG), it is concluded that, in the female guinea-pig, trenbolone acetate had no effect on LH-surge mechanism, but it may act on the pituitary gland to block the release of FSH.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2005. / Härtill 5 uppsatser.

Thesis (Ph. D.)--Louisiana State University, Baton Rouge, 2008. / Title from document title page.

No description available.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 57-62). Also available via the Internet.

My diploma thesis deals with doping and is specially focused on anabolic steroids. It was written in response to § 288 Criminal code, which newly describes production and other handling with hormonal effect as a delict in order to reduce the number of users, both among proffesional and among recreational sportsmen. It shows that sport federations have enough instruments to be able to face doping and that the newly adopted legal ragulation has a negative impact on human health, which is inconsistent with the reasons for which it was adopted.

<p> Resistance exercise and amino acids independently and synergistically stimulate muscle protein synthesis. Unloading of skeletal muscle depresses fasted state muscle protein synthesis, but the effect on the fed state response is unknown. Elucidation of the signaling pathways underlying the regulation of these processes in humans is in its infancy. Therefore, the purpose of this thesis was to determine how resistance exercise, feeding, and unloading interact to affect muscle protein turnover and its markers. In study 1 young men (N=9) underwent an acute bout of unilateral leg resistance exercise with or without feeding, with biopsies 6 h post exercise. Exercise dephosphorylated eiF2Bε and together with feeding potentiated the increase in phosphorylation of p70s6k and rps6. In study 2, 12 young people received primed constant infusions of 13C6-Phe in the fasted state and at one of two i.v. AA infusion rates (low, 42.5 mg/kg/h AA; high: 261 mg/kg/h AA) after 14 d of knee-brace mediated immobilization. Immobilization decreased fasted and fed state myofibrillar protein synthesis at both doses without obviously affecting translational signaling proteins. In study 3, two markers of muscle protein breakdown and oxidative damage were measured in 21 subjects (men, N=13, women, N=8) after 2 d and 14 d of knee-brace mediated immobilization. Protein ubiquitination was elevated after 2 d of immobilization but there was no sustained elevation in ubiquination at 14 d or increases in the 14kDa actin fragment or protein carbonyls and 4-hydroxy-2-nonenal. These studies support the concept that the responses of human muscle to changes in loading are primarily at the level of protein synthesis, and the p70 pathway appears to play a role in mediating the hypertrophic response. The currently known static markers of translational signaling and protein breakdown, however, are not very informative when attempting to account for an underlying molecular mechanism for disuse atrophy. </p> / Thesis / Doctor of Philosophy (PhD)