To the Editor.—
The old adage mice are not men seems again to have been demonstrated by Child et al in their article "Vasoconstrictor and Systemic Activities of Topical Steroids" in the April issue of the Archives. We are in complete agreement that, in the rodent fibroblast assay, thymolytic assay, and granuloma assay, betamethasone 17-valerate ranks considerably below the parent compound betamethasone in these measures of systemic activity. Unfortunately, they neglect to state that its activity topically, as measured by several other assays in rats, is also substantially below betamethasone. Thus, one must conclude that rats lack the ability to utilize this compound efficiently. Therefore, any inference based on these studies that betamethasone 17-valerate is systemically inactive in man is completely unsupported by the data in their article.Our vasoconstrictor studies1 in over 14,000 sites utilizing crystalline compounds in alcohol in randomized double-blind assay show betamethasone 17-valerate in man