A 2.6 kg rat needs to be dosed w / insulin. dosage is 10mg insulin/kg body weight. Given that concentration is 90mg/ml, how many microliters needed to dose rat?

You need 290 µL of insulin to dose the rat.

Mass of insulin = 2.6 kg rat * (10 mg insulin/1 kg rat) = 26.0 mg insulin

Millilitres of insulin = 26.0 mg insulin * (1 mL insulin/90 mg insulin)

= 0.289 mL insulin

Microlitres of insulin = 0.289 mL insulin * (1000 µL insulin/1 mL insulin)

= 290 µL insulin