[A_D_E_P_T]

> oxygen utilization, caloric expenditure, basal metabolism, blood volume, circulating plasma proteins, and renal function

The equation is from here: https://pubmed.ncbi.nlm.nih.gov/17942826/

For what it's worth, the rat equation is (X mg * (6/37))

Keep in mind that it's a loose/general guideline. Basically a starting point. But usually a quite accurate one.