Eugenia Dumitrescu

The Impact of Exogenic Testosterone and Nortestosterone-Decanoate Toxicological Evaluation Using a Rat Model

The impact of exogenic testosterone (T): 1.5 and 3.0 mg/kg.bw) and 19-nortestosterone 17-decanoate (ND): 1.5 and 7.5 mg/kg.bw) in castrated male rats was evaluated based on: (a) weight increase of the androgen target tissues, respecting the Hershberger methodology; (b) the 17α and β-testosterone, 17 α and β-estradiol and 17 α and β-nortestosterone levels using the GC-MS/MS technique; and (c) observation of the serum free thyroxine levels (T4). Results revealed that T and ND significantly increased the weight of androgen target tissues as follows: ND was more influential on seminal vesicles, levator ani-bulbocavernosus muscle (LABC) and Cowpers glands and T (at a dose of 3.0 mg/kg.bw) influenced the weight of the ventral prostate and glans penis. Serum samples analyzed for steroid hormone levels showed the presence of 17β-testosterone, 17β-estradiol and 17β-nor-testosterone, in castrated male rats injected with testosterone and nortestosterone, but no significant differences were found between thyroid responses and thyroid hormone levels. The results of this research proved the disrupting activity of T and ND when administered in high doses and the useful application of the Hershberger bioassay in the case of ND.

The consequences of aluminium intake on reproductive function in male rats: a three-generation study

BACKGROUND/AIM The effects of aluminium exposure on reproductive biomarkers in male rats were followed in a three-generation study. MATERIALS AND METHODS Forty Wistar male rats (F0) were divided into the following groups: control (C), receiving only tap water, and three experimental (E) groups, receiving aluminium sulphate (AS) (E1: 200 ppb, E2: 400 ppb, and E3: 1000 ppb) in drinking water for a 6-month exposure period. To obtain F1, three males from each group were mated with previously unexposed females (1:2 sex ratios) that during gestation and lactation were exposed to the same AS levels as males. The F1 generation male offspring were divided as described and exposed to the same AS levels. The protocol to obtain F2 was similar to that described for F1. RESULTS Significantly lower testosterone levels in rats exposed to AS and in generations F1 and F2 compared to the parental one, luteinising hormone (LH) fluctuations in F0 and a significant LH decrease in F2 and F3 generations, testis weight decrease, increased immobile and abnormal sperm, and histoarchitecture alterations in the testes were observed. Moreover, interval between deliveries increased. CONCLUSION Chronic exposure to AS was significantly deleterious, producing a pronounced decrease in the sperm count and testosterone levels in all experimental groups.

Application of QuEChERS - High PerformanceLiquid Chromatography with PostcolumnFluorescence Derivatization (HPLC-FLD) methodto analyze Eprinomectin B1a residues froma pour-on conditioning in bovine edible tissues

Abstract A QuEChERS in house method for determining the marker residue of eprinomectin (eprinomectin B1a) by HPLC-FLD in bovine tissues and milk provided from treated animals was developed and applied. Briefly: all samples were extracted with acetonitrile using a dispersive SPE purification stage. The ascertained detection limits were 1 μg kg-1 and the quantification limits 2 μg kg-1. Recoveries on tissue samples fortified in the range of 10 μg kg-1 to 200 μg kg-1 were from 80.0% to 87.2%, with variation coefficients between 2.7% to 10.6%. The confirmation of residues in the purified extracts was made by LC-MS/MS after separation on an XTerra MS C18 (10 cm × 2.1 mm, 3.5 μm) column with a mobile phase of acetonitrile / formic acid 0.1% (97:3, v/v) at a flow rate of 0.2 mL min-1 and MRM monitoring of three characteristic ions (m/z 896.1, m/z 467.9 and m/z 329.9), resulting from the fragmentation of molecular ions [M-H]+ (m/z 914.6) of eprinomectin and the comparison of the abundance ratio of fragmented ions was obtained in the booth, sample and standard at comparative concentrations. In conclusion, this method has proven its advantage and versatility as a routine drug residues analysis method. Graphical Abstract