Endocrinology, Vol 113, 1319-1324, Copyright © 1983 by Endocrine Society

ARTICLES

Human growth hormone and somatomedin C suppress the spontaneous release of growth hormone in unanesthetized rats

H Abe, ME Molitch, JJ Van Wyk and LE Underwood

To investigate the feedback control of GH secretion, we examined the effects of human GH (hGH) and somatomedin C (SmC) on spontaneous GH secretory surges in unanesthetized, freely moving rats. Under pentobarbital anesthesia a right atrial catheter and an intracerebroventricular cannula were placed 7-10 days before the experimentation. For iv studies, hGH (0.3 U/ml.h) was infused for 6 h after an iv loading dose (0.3 U) at the beginning of the experiments. For intraventricular injections, hGH (0.1 U/10 microliter) or SmC (500 ng/10 microliter) were injected into the lateral ventricle 2 h before the experiments. The equivalent dose of crystalline BSA diluted in the same vehicle solutions was administered to the same rat as a control on a separate day. Venous blood samples were collected every 20 min for 6 h. Intravenous and intraventricular administration of crystalline BSA did not affect the typical rat GH (rGH) surges which appeared about every 3 h and reached peak values of more than 300 ng/ml. The iv infusion of hGH significantly inhibited the amplitude of rGH surges compared to controls (planimetric areas under the secretory profile 752 +/- 172 vs. 1921 +/- 183, P less than 0.01, n = 6). rGH secretion was similarly inhibited by intraventricular hGH (701 +/- 127 vs. 2208 + 225, P less than 0.01, n = 6) and by intraventricular SmC (537 +/- 70 vs. 1503 +/- 114, P less than 0.01, n = 6). These findings suggest that both GH and SmC are active in the feedback regulation of rGH secretion.

This article has been cited by other articles:

				J. J. Kopchick, C. Parkinson, E. C. Stevens, and P. J. Trainer Growth Hormone Receptor Antagonists: Discovery, Development, and Use in Patients with Acromegaly Endocr. Rev., October 1, 2002; 23(5): 623 - 646. [Abstract] [Full Text] [PDF]

				E. Richmond, A. D. Rogol, D. Basdemir, O. L. Veldhuis, W. Clarke, C. Y. Bowers, and J. D. Veldhuis Accelerated Escape from GH Autonegative Feedback in Midpuberty in Males: Evidence for Time-Delimited GH-Induced Somatostatinergic Outflow in Adolescent Boys J. Clin. Endocrinol. Metab., August 1, 2002; 87(8): 3837 - 3844. [Abstract] [Full Text] [PDF]

				K. Wallenius, K. Sjogren, X.-D. Peng, S. Park, V. Wallenius, J.-L. Liu, M. Umaerus, H. Wennbo, O. Isaksson, L. Frohman, et al. Liver-Derived IGF-I Regulates GH Secretion at the Pituitary Level in Mice Endocrinology, November 1, 2001; 142(11): 4762 - 4770. [Abstract] [Full Text] [PDF]

				M. Maccario, F. Tassone, L. Gianotti, F. Lanfranco, S. Grottoli, E. Arvat, E. E. Muller, and E. Ghigo Effects of Recombinant Human Insulin-Like Growth Factor I Administration on the Growth Hormone (GH) Response to GH-Releasing Hormone in Obesity J. Clin. Endocrinol. Metab., January 1, 2001; 86(1): 167 - 171. [Abstract] [Full Text]

				L. Gianotti, M. Maccario, F. Lanfranco, J. Ramunni, L. Di Vito, S. Grottoli, E. E. Muller, E. Ghigo, and E. Arvat Arginine Counteracts the Inhibitory Effect of Recombinant Human Insulin-Like Growth Factor I on the Somatotroph Responsiveness to Growth Hormone-Releasing Hormone in Humans J. Clin. Endocrinol. Metab., October 1, 2000; 85(10): 3604 - 3608. [Abstract] [Full Text]

				L. Gianotti, A. I. Pincelli, M. Scacchi, M. Rolla, D. Bellitti, E. Arvat, F. Lanfranco, A. Torsello, E. Ghigo, F. Cavagnini, et al. Effects of Recombinant Human Insulin-Like Growth Factor I Administration on Spontaneous and Growth Hormone (GH)-Releasing Hormone-Stimulated GH Secretion in Anorexia Nervosa J. Clin. Endocrinol. Metab., August 1, 2000; 85(8): 2805 - 2809. [Abstract] [Full Text]

				S. Fruchtman, L. Jackson, and R. Borski Insulin-Like Growth Factor I Disparately Regulates Prolactin and Growth Hormone Synthesis and Secretion: Studies Using the Teleost Pituitary Model Endocrinology, August 1, 2000; 141(8): 2886 - 2894. [Abstract] [Full Text] [PDF]

				M. O. Thorner, C. J. Strasburger, Z. Wu, M. Straume, M. Bidlingmaier, S. S. Pezzoli, K. Zib, J. C. Scarlett, and W. F. Bennett Growth Hormone (GH) Receptor Blockade with a PEG-Modified GH (B2036-PEG) Lowers Serum Insulin-Like Growth Factor-I but Does Not Acutely Stimulate Serum GH J. Clin. Endocrinol. Metab., June 1, 1999; 84(6): 2098 - 2103. [Abstract] [Full Text]

				E. Ghigo, L. Gianotti, E. Arvat, J. Ramunni, M. R. Valetto, F. Broglio, M. Rolla, F. Cavagnini, and E. E. Müller Effects of Recombinant Human Insulin-Like Growth Factor I Administration on Growth Hormone (GH) Secretion, Both Spontaneous and Stimulated by GH-Releasing Hormone or Hexarelin, a Peptidyl GH Secretagogue, in Humans J. Clin. Endocrinol. Metab., January 1, 1999; 84(1): 285 - 290. [Abstract] [Full Text]

				A. Niiori-Onishi, Y. Iwasaki, N. Mutsuga, Y. Oiso, K. Inoue, and H. Saito Molecular Mechanisms of the Negative Effect of Insulin-Like Growth Factor-I on Growth Hormone Gene Expression in MtT/S Somatotroph Cells Endocrinology, January 1, 1999; 140(1): 344 - 349. [Abstract] [Full Text]

				R. G. Smith, L. H. T. Van der Ploeg, A. D. Howard, S. D. Feighner, K. Cheng, G. J. Hickey, M. J. Wyvratt Jr., M. H. Fisher, R. P. Nargund, and A. A. Patchett Peptidomimetic Regulation of Growth Hormone Secretion Endocr. Rev., October 1, 1997; 18(5): 621 - 645. [Abstract] [Full Text]

				J. Escalada, F. Sanchez-Franco, B. Velasco, and L. Cacicedo Regulation of Growth Hormone (GH) Gene Expression and Secretion During Pregnancy and Lactation in the Rat: Role of Insulin-Like Growth Factor-I, Somatostatin, and GH-Releasing Hormone Endocrinology, August 1, 1997; 138(8): 3435 - 3443. [Abstract] [Full Text] [PDF]

				D. Ray and S. Melmed Pituitary Cytokine and Growth Factor Expression and Action Endocr. Rev., April 1, 1997; 18(2): 206 - 228. [Abstract] [Full Text]

				E. Pellegrini, M. T. Bluet-Pajot, F. Mounier, P. Bennett, C. Kordon, and J. Epelbaum Central Administration of a Growth Hormone (GH) Receptor mRNA Antisense Increases GH Pulsatility and Decreases Hypothalamic Somatostatin Expression in Rats J. Neurosci., December 15, 1996; 16(24): 8140 - 8148. [Abstract] [Full Text] [PDF]