http://www.inchem.org/documents/jecf...no/v23je03.htm
Male calves that were 11 weeks of age received by s.c.
implantation 20 mg estradiol-17ß alone or 20 mg estradiol-17ß in
combination with 140 mg TBA. Urinary secretion of total steroid
estrogens was high in the animals given estradiol-17ß alone during the
first 12 days after application. After 3 weeks normal values were
reached. In the estradiol-17ß/TBA combination group, gradual and
prolonged excretion of steroid estrogens for up to 42 days after
implantation occurred; after 56 days normal values were reached.
Qualitative determinations of estradiol-17ß and estradiol-17ß in urine
showed that the alpha epimer was present in almost all urine samples;
estradiol-17ß was found in the urine of those calves administered
estradiol-17ß alone. In the combination group, estradiol-17ß was found
in urine at day 21 only. Histological examination of prostates
revealed squamous metaplasia of gland epithelium after both treatments
(Kroes et al., 1976b).
Heifers (aged 15 months, number not given) were given daily oral
doses of 0.4 or 8 mg TBA per animal for 9 weeks. After 1 and 2 weeks
TBA was detected in the urine. Two weeks after drug withdrawal the
compound was detected in some urine samples, whereas after 3 weeks no
TBA was detected (Stephany et al., 1976).
Groups of 3 - 4 bull calves were given s.c. implantations of
20 mg 3H-estradiol-17ß or 20 mg 3H-estradiol-17ß + 140 mg TBOH.
TBOH caused a marked delay in estradiol excretion. In calves receiving
estradiol only, the maximum plasma estradiol-17ß level was 3 nmole/l,
and 95% of the applied radioactivity was excreted in the urine and
faeces within 20 days; after more than 31 days radioactivity was no
longer detectable in the urine or faeces. Calves treated with TBOH
showed a maximum plasma estradiol-17ß level of 0.33 nmole/l and
excretion of radioactivity was observed up to 107 days after
administration; at that time faecal and urinary radioactivity levels
were still 1.4 - 3 nCi/g (Riis & Suresh, 1976).
In two barren cows after s.c. implantation of 300 mg 3H-TBA per
animal at the base of the ear, slow resorption from the implant
occurred; the half-life of disappearance from the implant was 68 - 84
days. About 33% of the radioactivity was extracted in the blood plasma
over the 3-month period after implantation, 70% of which was accounted
for by TBOH. The main routes of excretion were via the bile and urine.
Tissue levels after 3 months were about 1 ppb, except in the liver
(6.5 ppb) and kidneys (4.5 ppb). Twenty-five percent of the tissue
radioactivity was extractable, 40% of which was TBOH. In the liver and
kidneys, however, only 10% was extractable, while in perirenal fat up
to 88% of the radioactivity was extractable. In perirenal fat 50% of
the radioactivity was TBA. Radioactivity levels in the implantation
zone were 8 - 21% of the implanted quantity (Pottier et al., 1973;
Pottier et al., 1975).
Pigs (males, females, and castrated males) were given s.c.
implantations with either 20 mg estradiol-17ß or 20 mg estradiol-17ß
in combination with 140 mg TBA. At 5 weeks after implantation, steroid
estrogens were hardly detectable in the faeces, and serum values for
estradiol-17ß were very low in both groups. Urine estradiol-17ß levels
were 6 - 82 µg/l in the estradiol-17ß group and 16 - 135 µg/l in the
combination group (Kroes et al., 1976a).
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Originally Posted by odrorir
