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Residues from anabolic preparations after _good veterinary practice *
Author(s) -
HENRICKS D. M.,
GRAY S. L.,
OWENBY J. J.,
LACKEY B. R.
Publication year - 2001
Publication title -
apmis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0903-4641
DOI - 10.1111/j.1600-0463.2001.tb05786.x
Subject(s) - implant , anabolism , radioimmunoassay , estrone , endocrinology , medicine , adipose tissue , gestation , skeletal muscle , endogeny , chemistry , zoology , biology , hormone , surgery , pregnancy , genetics
The purpose of this study was to determine the endogenous concentrations of estrogens, particularly estradiol‐17β (E 2 β), in edible tissues of beef cattle (females and intact and neutered males) and the concentrations of E 2 β, and trenbolone beta and alpha (βTb, αTb) after an E 2 β and/or trenbolone acetate (TA) ear implant. Radioimmunoassays were validated for quantitation of E 2 β (active isomer), E 2 α, estrone (E 1 ), βTb and αTb for bovine muscle, liver, kidney and fat tissues. The criteria of accuracy, precision, specificity and sensitivity were applied according to the standards of the U.S. Food & Drug Administration. In steer tissues, endogenous E 2 β was <15 ppt, as was heifer muscle; but heifer liver and kidney were 3‐fold greater. An E 2 β implant in steers had no effect on muscle E 2 β concentration, but increased E 2 β in liver and fat 4‐ and 3‐fold, respectively, but by 24 h post‐implant removal, E 2 β had fallen by half. Tissue E 1 concentrations in cyclic females were similar to E 2 β, but rose many fold greater than did E 2 β during gestation; E 2 β rose 3‐fold during gestation. After E 2 β/TA implant, steer tissues had E 2 β concentrations equal to (for muscle and fat) and one‐half (for liver) the E 2 β measured in E 2 β implant only steers; βTb was in a low range (250–380 ppt) in muscle, liver and fat and αTb was even lower, except in liver (800–1500 ppt). An implant of TA only (no E 2 β) resulted in βTb and αTb concentrations 2–3‐fold greater in liver, kidney and fat, but no greater in muscle than βTb in tissues of E 2 β/TA implant steers. In conclusion, anabolic implants in steers resulted in tissue E 2 β concentrations less than the FDA allowable increment and βTb in the lowest quartile (0.25) of a part per billion 30 days after implant.