Effect of growth hormone-secreting tumors on body composition and feed intake in young female Wistar-Furth rats.

Growth hormone (GH) was elevated in young growing, intact female Wistar-Furth rats bearing growth hormone (GH1) or growth hormone and prolactin (GH3) secreting tumors. Animals were injected with GH1 or GH3 cells at 1 wk of age. Total feed intake was measured for the 8-wk period from weaning until killed at 11 wk of age. Animals were fed a commercial chow diet throughout the trial. Body composition and composition of the liver and tibialis anterior muscle were determined. Tumor-bearing rats were about 65% heavier than control rats at 11 wk of age: most of the difference in body weight gain was obtained during the last 4 wk of the trial. Total feed intake during the 8 wk after weaning was increased in both GH1 and GH3 tumor-bearing rats when compared with controls. Overall feed efficiency (grams feed consumed/gram body weight gain) was improved in tumor-bearing animals when compared with controls. The GH1 tumor-bearing rats were slightly hyperphagic during wk 8, 9 and 10 (grams feed consumed/gram body weight) when compared with controls. The total amount of body dry matter, protein and ash was increased in tumor-bearing rats when compared with controls. There was no effect on total body fat. Tumor-bearing rats had increased liver weight and increased fat, protein, RNA, DNA and dry matter content when compared with controls. Tumor induction increased the weight, total RNA and total fat content of the tibialis anterior muscle when compared with controls. There was no effect on muscle protein content.(ABSTRACT TRUNCATED AT 250 WORDS)