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F Neumann

Publications and source records attributed to F Neumann.

At least 91 records · Page 5Linked to original sources
PubMed1976

Pharmacological and endocrinological studies on anabolic agents.

When used in connection with animal production the term "anabolic agents" covers a wide range. Ther steroidal male and female sex hormones are included in this list, as are the nonsteroidal estrogens. For the clinician and for the endocrinologist, anabolics are only steroids chemically related to testosterone and 19-nortestosterone. Estrogens, though possessing anabolic properties, too, do not belong to this class. This paper will deal with anabolic agents in in the stricter sense of which mainly trenbolone acetate combined with hexestrol has been recommended for bull and heifer fattening. To consider possible consumer injury from ingestion of meat from anabolic agent treated animals, it is necessary to know the pharmacological properties of the agents, the doses producing certain effects or might produce, and the levels of residues in the meat. Trenbolone acetate will be compared with the following anabolic agents: methenolone acetate, methandrostenolone, nandrone, androstanazole, and 19-nortestosterone. The activity spectrum of trenbolone acetate is similar to that of 19-nortestosterone or those anabolics that are derived from 19-nortestosterone. The compound has about three times stronger androgenic effect than testosterone propionate. Its index of dissociation between anabolic/androgenic activity is 2--3. This index is 3--10 for the other anabolic agents. As regards the virilizing potency, trenbolone acetate is also on the top of the list. It seems that androgenicity and degree of virilization run paralle. The antigonadotropic activity (inhibition of ovulation and testicular growth) of trenbolone acetate exceeds that of testosterone propionate by the factor 3. The compound is not estrogenic and seemingly not or only weakly progestationally active. In principle, the androgenic activity (symptoms of virilization) as well as the antigonadotropic effect (disturbances of the menstrual cycle in women, inhibition of spermiogenesis in men) of trenbolone acetate might be noted. This risk, however, can be excluded by mere calculation. In rats, 0.1 mg/kg trenbolone acetate have an antigonadotropic effect. This corresponds to a daily dose of 5--7 mg in humans. By the same extrapolation, a daily human dose of 100 mg can be calculated for androgenic activity. Such factors of conversion are, of course, not precise because rats are much less sensitive to androgens and anabolics than humans. Thus, testosterone propionate is active only in daily doses of 10--20 mg. If in humans trenbolone acetate also has three times the activity of testosterone propionate, effects in man had to be counted with not less than a daily intake of 3--5 mg trenbolone acetate. The dose which is recommended for livestock fattening is 300 mg. IT can, therefore, be excluded almost with certainty that the meat would contain such large amounts of hormone residues.

Anabolic Agents↗
PubMed1975

Partial feminization of hepatic steroid metabolism in male rats after neonatal administration of cyproterone acetate.

The metabolism of (4-14C)4-androstene-3,17-dione, (4-14C)5alpha-androstane-3alpha, 17beta-diol and (1,2-3H)5alpha-androstane-3alpha, 17beta-diol 3,17-disulphate was studied using the microsomal fraction and the metabolism of (4-14C)4-androstene-3,17-dione was studied using the 105 000 g supernatant fraction of liver from male and female rats aged 5 months that had been treated with cyproterone acetate before (from day 13 of pregnancy) and after birth (until 3 weeks of age). Nearly all sex-dependent enzyme activities in the treated male rats were changes in a direction characteristic of female rats: 5alpha-reductase active on 4-androstene-3,17-dione increased in activity whereas 3beta- and 17alpha-hydroxysteroid reductases and 6beta- and 16alpha-hydroxylases active on 4-androstene-3,17-dione and 2alpha-, 2beta- and 18-hydroxylases active on 5alpha-androstane-3alpha,17beta-diol decreased in activity. Enzyme activities not under gonadal control, i.e. 3alpha- and 17beta-hydroxysteroid reductases active on 4-androstene-3,17-dione and 7alpha-hydroxylase active on both 4-androstene-3,17-dione and 5alpha-androstane-3alpha, 17beta-diol, were not affected by cyproterone acetate. The liver enzyme activities in treated female rate were generally not affected although significant effects were noted in two cases; in one of these (17alpha-hydroxysteroid reductase) a testosterone-like effect was observed. The results obtained are probably best explained in the following way: treatment with theanti-androgen during the neonatal period results in less efficient imprinting of the hypothalamo-hypophysial system leading to less pronounced masculine setting of sex-dependent enzyme levels and also to a relative androgen unresponsiveness. It is suggested that the biochemical methods used in the degree of neonatal sexual differentiation of the hypothalamo-hypophysial system than biological and psychological methods previously available.

Androstanes↗