The objective of this study was to compare the responsiveness of human subjects to the anabolic effects of human growth hormone (HGH) administered at 8 a.m. or at 11 p.m. Three doses of HGH were used: A, 0.0168 U/kg body weight (BW)3/4 per day; B, 0.0532 U/kg BW3/4 per day; C, 0.168 U/kg BW3/4 per day. The effect of each dose on daily balances of N, P, Na, and K and on BW was measured. The subjects were of two groups: (a) seven GH-deficient children, of whom three were deficient in ACTH; and (b) three patients with limb-girdle dystrophy. ACTH-deficient patients in group (a) received exogenous cortisol at 7 a.m. In all 10 subjects, the anabolic effects of dose C, and sometimes of B and A, administered at 11 p.m. were significantly (P < 0.05) greater than when administered at 8 a.m. In these experiments plasma cortisol concentration averaged 3 times greater at 8 a.m. than at 11 p.m.
Daniel Rudman, David Freides, Joseph H. Patterson, Donna L. Gibbas