The influence of dexamethasone on the regrowth of surgically removed fat.

We investigated the interaction between long-term dexamethasone administration and lipectomy on regional fat deposits in the rat. Seven-week-old Sprague-Dawley rats (N = 24) were divided into 3 test groups. Group 1 (control) received 0.5 ml/kg of saline intramuscularly daily; group 2, 1 microgram dexamethasone intramuscularly; group 3, 5 micrograms dexamethasone intramuscularly. At week 9 a lipectomy of 4 regional fat deposits on the right side of the animal was done: inguinal, epididymal, interscapular, and perirenal. Injections continued for an additional 27 weeks, at which time a lipectomy was done removing left-sided depots in addition to any "regrown fat" on the previously dissected right side. Several conclusions can be made. First, rats receiving 5 micrograms/kg reaccumulated more fat than the controls in the inguinal, perirenal, and interscapular depots. Second, fat cell size in this model greatly influenced the ultimate size of each depot. Third, fat depots vary in their response to steroids and lipectomy because of local and systemic factors.