Influence of anabolic combinations of an androgen plus an estrogen on biochemical pathways in bovine uterine endometrium and ovary.

The application of anabolic steroids in food producing animals is forbidden in the EU since 1988, but the abuse of such drugs is a potential problem. The existing test systems are based on known compounds and can be eluded by newly emerging substances. The examination of physiological effects of anabolic hormones on different tissues to indirectly detect misuse might overcome this problem. Two studies were conducted with post-pubertal 24-months old Nguni heifers and pre-pubertal female 2-4 weeks old Holstein Friesian calves, respectively. The animals of the accordant treatment groups were administered combinations of estrogenic and androgenic compounds. The measurement of the gene expression pattern was undertaken with RT-qPCR. Target genes of different functional groups (receptors, angiogenesis, steroid synthesis, proliferation, apoptosis, nutrient metabolism and others) have been quantified. Several biochemical pathways were shown to be influenced by anabolic treatment. Both studies identified significant regulations in steroid and growth factor receptors (AR, ERß, LHR, FSHR, Flt-1, PR, IGF-1R, Alk-6), angiogenic and tissue remodeling factors (VEGFs, FGFs, BMPs, ANGPT-2, MMPs, TIMP-2, CTSB), steroid synthesis (S5A1, HSD17, CYP19A1), proliferation (TNFα, IGF-1, IGFBPs, p53, c-fos; CEBPD, c-kit), apoptosis (CASP3, FasL, p53) and others (C7, INHA, STAR). Several genes were regulated to opposite directions in post-pubertal compared to pre-pubertal animals. PCA for Nguni heifers demonstrated a distinct separation between the control and the treatment group. In conclusion, anabolics modify hormone sensitivity and steroid synthesis, and they induce proliferative effects in the whole reproductive tract (uterus and ovary) as well as anti-angiogenic effects in the ovary. However, the extent will depend on the developmental stage of the animals.

The potential of bovine vaginal smear for biomarker development to trace the misuse of anabolic agents.

In the European Union the use of anabolic hormones in meat production is forbidden since 1988 and this ban of anabolic agents in animal production is strictly controlled. New hormone cocktails passing the detection systems are attractive for the practice and so new approaches to discover their illegal use have to be developed steadily. Verifying physiological effects caused by anabolic steroids will be a new way to develop potential monitoring systems. One promising matrix in female animals will be vaginal smear containing vaginal epithelial cells, because the vaginal epithelium is a primary steroid hormone responsive organ. In this study we quantified the gene expression in vaginal smear of sexually mature cattle in order to observe physiological effects. Further we aimed to establish a new screening method by testing the effect of a combination of certain anabolic steroid hormones on physiological regulations of mRNA expression of selected genes. In an animal trial Nguni heifers were treated with the anabolic combination trenbolone acetate plus estradiol. Vaginal smear samples were taken at 4 different time points. Gene expression of 27 candidate genes, selected by screening the actual literature for steroidal effects on vaginal epithelial cells, were estimated using quantitative real-time RT-PCR. There were different expression changes observed at different time points. It could be shown that the applied anabolic combination significantly influenced the expression of the steroid receptor ERα, the keratinization factor CK8, the proinflammatory interleukins IL-1α and IL-1ß, the growth factors FGF7, EGF, EGFR, IGF-1R, TGFα and LTF, the oncogen c-jun and other factors like actinß and ubiquitin 3. Using biostatistical tools like principal components analysis or hierarchical cluster analysis, the potential to develop a gene expression pattern for targeting the illegal use of growth promoters could be demonstrated.

mRNA and microRNA quality control for RT-qPCR analysis.

The importance of high quality sample material, i.e. non-degraded or fragmented RNA, for classical gene expression profiling is well documented. Hence, the analysis of RNA quality is a valuable tool in the preparation of methods like RT-qPCR and microarray analysis. For verification of RNA integrity, today the use of automated capillary electrophoresis is state of the art. Following the recently published MIQE guidelines, these pre-PCR evaluations have to be clearly documented in scientific publication to increase experimental transparency. RNA quality control may also be integrated in the routine analysis of new applications like the investigation of microRNA (miRNA) expression, as there is little known yet about factors compromising the miRNA analysis. Agilent Technologies is offering a new lab-on-chip application for the 2100 Bioanalyzer making it possible to quantify miRNA in absolute amounts [pg] and as a percentage of small RNA [%]. Recent results showed that this analysis method is strongly influenced by total RNA integrity. Ongoing RNA degradation is accompanied by the formation of small RNA fragments leading to an overestimation of miRNA amount on the chip. Total RNA integrity is known to affect the performance of RT-qPCR as well as the quantitative results in mRNA expression profiling. The actual study identified a comparable effect for miRNA gene expression profiling. Using a suitable normalization method could partly reduce the impairing effect of total RNA integrity.

Detectability of testosterone esters and estradiol benzoate in bovine hair and plasma following pour-on treatment.

The abuse of synthetic esters of natural steroids such as testosterone and estradiol in cattle fattening and sports is hard to detect via routine urine testing. The esters are rapidly hydrolysed in vivo into substances which are also endogenously present in urine. An interesting alternative can be provided by the analysis of the administered synthetic steroids themselves, i.e., the analysis of intact steroid esters in hair by liquid chromatography tandem mass spectrometry (LC/MS/MS). However, retrospective estimation of the application date following a non-compliant finding is hindered by the complexity of the kinetics of the incorporation of steroid esters in hair. In this study, the incorporation of intact steroid esters in hair following pour-on treatment has been studied and critically compared with results from intramuscular treatment. To this end animals were pour-on treated with a hormone cocktail containing testosterone cypionate, testosterone decanoate and estradiol benzoate in different carriers. The animals were either treated using injection and pour-on application once or three times having 1 week between treatments using injection and pour-on application. Animals were slaughtered from 10-12 weeks after the last treatment. Both hair and blood plasma samples were collected and analysed by LC/MS/MS. From the results, it is concluded that after single treatment the levels of steroid esters in hair drop to CCbeta levels (5-20 microg/kg) after 5-7 weeks. When treatment is repeated two times, the CCbeta levels are reached after 9-11 weeks. Furthermore, in plasma, no steroid esters were detected; not even at the low microgramme per litre level but--in contrast with the pour-on application--after i.m. injection, significant increase of 17beta-testosterone and 17beta-estradiol were observed. These observations suggest that transport of steroid esters after pour-on application is not only performed by blood but also by alternative fluids in the animal so probably the steroid esters are already hydrolysed and epimerized before entering the blood.