ABSTRACT
The maintenance of activity of hormonal preparations is determined by continued availability from the implant and by retention in tissues in the active form. These, along with metabolized and variably inactivated forms, contribute to
Horm ones-
Lam b
the presence of residues in meat postmortem. Metabolic inactivation is effected predominantly by liver CYP450 systems with elimination, for example, following hydroxylation or sulphation in urine or if more lipophilic via bile, with the additional possibility of reabsorption.[4] An issue of increasing contemporary importance is persistence in the environment of excreted compounds, including the nonabsorbed fraction for MGA, and subsequent re-entry to the water or food chain.[8]
Assessment of Risk to Human Consumers
For human beings, consumption of meat containing hormones and their residues involves absorption from digested products, systemic transport in blood (usually proteinbound), metabolism, and excretion in urine and feces with retention in some body tissues.[4] Important issues include the physiological status of human consumers, concentrations and production rates of endogenous sex hormones, sensitivity of prepubertal children, and short-and longterm effects of embryonic and fetal exposure in utero. Xenobiotic hormones that do not occur naturally in animals require consideration in the context of absolute quantities.
