RECOMBINANT HUMAN GROWTH-HORMONE MODIFIES THE INHERENT PARTITION OF NUTRIENTS IN GROWING FEMALE AND MALE BALB C MICE/

BALB/c mice weaned at 21 days were used to investigate the effects of exogenous recombinant human growth hormone (rhGH) administration on th e growth performance and carcass composition in females and males allo wed to consume feed ad libitum. Forty mice were assigned within each s ex (female [F] and male [M]) to treatment of either 20 mu L g(-1) sali ne (Fs and Ms groups) or 74 ng rhGH g(-1) body weight (BW) in 20 mu L saline (FGH and MGH groups). At 50 d of age the mice were weighed and then killed by cervical dislocation. Treatment with rhGH improved feed conversion only in growing female mice by enhancing weight gain relat ive to feed and protein intake and weight growth rate without modifica tion of feed consumption, according to a multiple comparison test (LSD ). Ms mice showed less carcass fat gain (162%), less far accretion rat e (129%), higher carcass water gain (12%) and higher water accretion r ate (28%) than Fs mice. The administration of rhGH modified this distr ibution inducing an increase in gain and accretion rates of protein (3 4%), water (41%) and ash (33%) and a reduction in gain and accretion r ate of fat (50%) in FGH mice, and only an increase of gain (91%) and a ccretion rate of fat (67%) in MGH mice compared to saline mice. As res ult, a decrease in protein gain:fat gain ratio of MGH mice compared to FGH (34%) and Ms (63%) mice was elicited by rhGH, inverting the inher ent sexual propensity for fat and protein deposition in growing male m ice, due to GH, sex, and to GH x sex interaction influence. Copyright (C) 1996 Elsevier Science Inc.