Growth hormone pulsatility profile characteristics following acute heavy resistance exercise

• Published in: Journal of applied physiology (1985) 2001-07, Vol.91 (1), p.163-172
• Main Authors: Nindl, Bradley C, Hymer, Wesley C, Deaver, Daniel R, Kraemer, William J
• Format: Article
• Language: English
• Subjects: Adult; Biological and medical sciences; Exercise; Fundamental and applied biological sciences. Psychology; Hormones; Hormones and neuropeptides. Regulation; Human Growth Hormone - blood; Humans; Hypothalamus. Hypophysis. Epiphysis. Urophysis; Immunoassay; Immunoradiometric Assay; Male; Osmolar Concentration; Physical growth; Pulsatile Flow; Radioimmunoassay; Time Factors; Vertebrates: endocrinology; Weight Lifting - physiology
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.2001.91.1.163

1  Intercollege Graduate Program in Physiology, 2  General Clinical Research Center at Noll Laboratory, 3  Department of Kinesiology, 4  Department of Biochemistry and Molecular Biology, and 5  Department of Animal Sciences, The Pennsylvania State University, University Park, Pennsylvania 16801; and 6  The Human Performance Laboratory, Ball State University, Muncie, Indiana 47306 This investigation examined the hypothesis that acute heavy resistance exercise (AHRE) would increase overnight concentrations of circulating human growth hormone (hGH). Ten men (22 ± 1 yr, 177 ± 2 cm, 79 ± 3 kg, 11 ± 1% body fat) underwent two overnight blood draws sampled every 10 min from 1700 to 0600: a control and an AHRE condition. The AHRE was conducted from 1500 to 1700   and was a high-volume, multiset exercise bout. Three different immunoassays measured hGH concentrations: the Nichols immunoradiometric assay (Nichols IRMA), National Institute of Diabetes and Digestive and Kidney Diseases radioimmunoassay (NIDDK RIA), and the Diagnostic Systems Laboratory immunofunctional assay (DSL IFA). The Pulsar peak detection system was used to evaluate the pulsatility profile characteristics of hGH. Maximum hGH was lower in the exercise (10.7 µg/l) vs. the control (15.4 µg/l) condition. Mean pulse amplitude was lower in the exercise vs. control condition when measured by the Nichols IRMA and the DSL IFA. A differential pattern of release was also observed after exercise in which hGH was lower in the first half of sleep but higher in the second half. We conclude that AHRE does influence the temporal pattern of overnight hGH pulsatility. Additionally, because of the unique molecular basis of the DSL IFA, this influence does have biological relevance because functionally intact molecules are affected. immunofunctional assay; somatotropin; strength training