Similarities and differences between effects of testosterone and 19-nortestosterone in rats, with particular reference to hypertensogenic potency

Monoclonal antibody-based ELISA and colloidal gold immunoassay for detecting 19-nortestosterone residue in animal tissues

This article presents the generation of monoclonal antibodies (mAbs) with high specificity against 19-nortestosterone (NT) through cell fusion techniques and the development of a mAb-based indirect competitive ELISA (icELISA) method and colloidal gold-based immuno-chromatographic assay to detect NT residues in beef and pork samples. A modified carbodiimide method was employed to synthesize the artificial antigen, and BALB/c mice were used to produce anti-NT mAbs. On the basis of the checkerboard titration, an indirect competitive ELISA standard curve was established. This assay was sensitive and had a linear range from 0.03 to 38 ng/mL in phosphate buffered saline (PBS), with IC(50) and LOD values of 0.52 ng/mL and 0.01 ng/mL, respectively. Of all the competitive analogues, the produced mAb exhibited a high cross-reactivity to 17α-nortestosterone (83.6%), the main metabolite of NT in animal tissues. Except for moderate cross-reactivities with trenbolone (22.6%) and β-boldenone (13.8%), the other interference to the assay was negligible (<0.05%). In contrast, the strip test had a visual detection limit of 1 ng/mL in PBS, 2 μg/kg in beef, and 2 μg/kg in pork, respectively, and the results can be judged within 10 min. The ELISA and GC-MS results showed close correlation in beef (R2=0.9945) and in pork (R2=0.9977). Therefore, the combination of two immunoassays provides a useful screening method for quantitative or qualitative detection of NT residues in animal-origin products.

The inhibition of rat adrenal cytochrome P-45011 beta gene expression by androgens

The synthetic androgen methylandrostenediol (MAD) and the naturally occurring one, testosterone, both bring about hypertensive cardiovascular disease when chronically administered to rats. The pathogenesis of this form of experimental hypertension is thought to result from inhibition of steroid 11 beta-hydroxylase activity. In contrast to the above androgens, 19-nortestosterone, androstenedione and dehydroepiandrosterone (DHEA) have been reported to be without effect in elevating blood pressure. To examine the mechanism(s) involved, we have in this study compared the effects of a number of androgens on adrenal cytochrome P- 45011 beta enzyme and mRNA steady state levels. These parameters were also correlated with the ability of adrenal mitochondria isolated from these groups to hydroxylate 11-deoxycorticosterone (DOC) to corticosterone and 18-hydroxy-11-deoxycorticosterone (18-hydroxy-DOC). Rats treated for seven days with 10 mg per day of dihydrotestosterone, testosterone, 19-nortestosterone or MAD showed a profound decrease in cytochrome P-45011 beta mRNA levels (to less than 20% of controls). This was accompanied by similar changes in both the level and activity of the enzyme. Androstenedione and DHEA were less potent in effecting these changes. In addition, for MAD and testosterone we tested the dose dependence of these changes and found that increasing doses (0.1 mg to 10 mg per day) of either androgen caused progressive decreases in the parameters measured. To assess selectivity we also determined the steady state level of cytochrome P-450scc mRNA in rats treated with the various androgens. In contrast to what was found with cytochrome P-45011 beta, the mRNA transcript for cytochrome P-450scc was equal to or above control levels. We conclude that, in general, the extent of inhibition of cytochrome P-45011 beta enzyme and mRNA level by a given androgen correlates with its reported facility in producing hypertension in rats. Increased secretion of DOC continues to be a likely mechanism for the development of this hypertension but with some androgens extra-adrenal effects may be involved.

Risks of blood volume changes in hypogonadal men treated with testosterone enanthate for erectile impotence

Administration of anabolic steroids carries many risks. We present a series of 15 patients with primary hypogonadism who as a group had statistically significant increases in whole body hematocrit and red blood cell volume while on testosterone therapy of 300 mg. intramuscularly every 3 weeks. A small decrease in plasma volume over-all was not significant. Subsequent analyses compared subgroups whose whole body hematocrit during testosterone therapy was either 48% or greater (9) or less than 48% (6). Interaction effects indicated that the subgroups were similar when off testosterone but when on testosterone the former group exhibited an increase in red blood cell volume and a decrease in plasma volume, while the latter group had little change in either measurement. Subsequent to stopping testosterone therapy 2 patients in the whole body hematocrit 48% or greater group suffered strokes and 1 had transient ischemic attacks while on therapy. No one in the whole body hematocrit less than 48% group has had any cerebrovascular symptoms. Clinical implications, as well as cost-effective and practical suggestions for detecting possible dangerous hemoconcentration are discussed.

Neuronal sensitivities in preoptic tissue slices: interactions among homeostatic systems

The preoptic area participates in many homeostatic systems, which include the regulation of body temperature, fluid and metabolite balance, and reproduction. Some preoptic neurons have been shown to be sensitive to either temperature, osmotic pressure, glucose, testosterone or estradiol. While previous studies have treated these as separate and distinct neuronal populations, this paper reviews recent experiments which show that many neurons have multiple sensitivities to these endogenous factors. Neurons in preoptic tissue slices were tested for their responses to changes in temperature, as well as various perfusion media containing 30 pg/ml testosterone or estradiol, low glucose (1.0 mM) or increased osmotic pressure (309 mosmol/kg). The steroid-sensitive, osmosensitive and glucosensitive neurons were not confined to the temperature insensitive neurons; but instead nearly half of the thermosensitive neurons responded to these nonthermal stimuli. In addition, many osmosensitive neurons showed glucosensitivity and steroid-sensitivity. This suggests that, even at the neuronal level, there is a basis for interactions between homeostatic systems.

Clinical trial of 19-nortestosterone-hexoxyphenylpropionate (Anadur) for male fertility regulation

To test the effectiveness of 19-nortestosterone (19NT) as an antifertility agent, 12 normal men (age, 24.0 +/- 2.2 years) received 19NT-hexoxyphenylpropionate (19NT-HPP), 200 mg/week intramuscularly for 7 weeks. After this initial phase, two groups were formed that received injections at different intervals. Except for the 19NT serum levels, there was no difference in treatment effects between both groups. 19NT-HPP administration in general suppressed gonadotropins below detection limits, accompanied by testosterone levels well in the castrate range. At the end of the treatment phase, azoospermia or severe oligozoospermia (total sperm count less than 5 X 10(6)) was present in ten volunteers. No loss of libido or potency was reported. Administration of 19NT-HPP did not affect liver enzymes, creatinine, uric acid, serum electrolytes, or serum lipids. The presented data demonstrate that 19NT-HPP as a single entity given every 3 weeks can suppress sperm output in a high proportion of men and simultaneously maintain virility.