Sulfate pathways

In general, phase I reactions, such as oxidation and ra-demethylation are delayed in the neonate but are fully operational at or above adult levels by 4-6 months of age in the full-term neonate [27a-30]. Conjugation pathways, such as glucuronidation, do not approach adult values until 3 or 4 years of age. Sulfation activity does appear to reach adult levels in early infancy. For drugs that are subject to metabolism by both pathways, such as acetaminophen, the efficient activity of the sulfation pathway allows infants and children to compensate for low glucuronidation ability... 

Coughtrie, M. W. H., S. Sharp, K. Maxwell, and N. P. Innes. Biology and function of the reversible sulfation pathway catalyzed by human suIfotransferases and sulfatases. Chemico-Biol. Inter. 109 3-27, 1998. 

Coughtrie, M.H., Sharp, S., Maxwell, K., and Innes, N.P., Biology and function of the reversible sulfation pathway catalysed by human sulfotransferases and sulfatases, Chem. Biol. Interact., 109, 3, 1998. 

If the dose of drug is high, the sulfate pathway can become saturated and other conjugation reactions (such as glucuronide formation) can take over. This is because the reservoir of inorganic sulfate in the body is finite and is easily overloaded. 

It was thus established that the enzymes involved in the biosynthesis of adrenal androgens could have sulfo conjugated compounds as substrates, but one had yet to discover whether cholesterol sulfate was the initial precursor and what was the quantitative importance of this sulfate pathway. 

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