title: Differential effects of feeding on the ultradian variation of the growth hormone (GH) response to GH-releasing hormone in normal subjects and patients with obesity and anorexia nervosa.
abstract: Nutritional status and metabolic fuels are factors involved in the regulation of GH secretion and GH responses to GHRH. The effects of feeding on GHRH-induced GH release were studied in 13 normal women, 14 obese women, and 9 women with anorexia nervosa. GHRH-(1-44) (50 micrograms, iv) was administered at 0900 h after an overnight fast or at 1300 h after a normal meal at 0800 h, and at the same times 45 min after a 800-Cal meal on different days. The mean peak plasma GH responses to GHRH administered before a meal at 0900 h were 52.8 +/- 5.6 (+/- SE) micrograms/L in normal women, 8.2 +/- 1.3 micrograms/L in obese women, and 53.2 +/- 7.7 micrograms/L in anorexic women. When GHRH was administered before a meal at 1300 h, the mean peak plasma GH levels were lower than those at 0900 h; this reduction was -64.2% in normal women, -64.9% in obese women, and -55.8% in women with anorexia nervosa. After feeding, the plasma GH responses to GHRH were blunted in normal women at 0900 h (-60.9%) and 1300 h (-34.6%) compared with the fasting peak responses. In obese women the plasma GH response to GHRH after feeding was increased compared with that when these women had fasted (+60% at 0900 h and +406.9% at 1300 h). Finally, differential effects of feeding were present in anorexic women; the response was lower at 0900 h (-46.4%) and greater at 1300 h (+50.8%). We conclude that there is an ultradian variation in GHRH-stimulated GH secretion and that the responses differ according to nutritional status and body weight.
mesh_terms: D000328:Adult; D000856:Anorexia Nervosa / Q000097:blood / Q000503:physiopathology*; D001786:Blood Glucose / Q000378:metabolism; D002940:Circadian Rhythm; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D005502:Food; D013006:Growth Hormone / Q000097:blood*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D006801:Humans; D009752:Nutritional Status; D009765:Obesity / Q000097:blood / Q000503:physiopathology*
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone