rat unit


Also found in: Acronyms.

rat unit

An obsolete, semi-quantitative unit corresponding to the minimum amount of an oestrogenic substance required to produce characteristic desquamation of vaginal epithelium in ovarectomised rats.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

rat unit

,

R.U.

The greatest dilution of estrogen that will cause desquamation and cornification of the vaginal epithelium if given to a mature spayed rat in three injections, one every 4 hr.
Medical Dictionary, © 2009 Farlex and Partners