The interrelationship of growth hormone (GH)-releasing factor and somatostatin in generation of the ultradian rhythm of GH secretion
- PMID: 6149116
- DOI: 10.1210/endo-115-5-1952
The interrelationship of growth hormone (GH)-releasing factor and somatostatin in generation of the ultradian rhythm of GH secretion
Abstract
To further delineate the relationship between GH-releasing factor (GRF) and somatostatin (SRIF) in generation of the ultradian rhythm of GH secretion, we used two GRF peptides, human pancreas (hp) GRF-44 and rat hypothalamic (rh) GRF, and studied their interaction with SRIF by passive immunization with a specific antiserum (AS) to SRIF. Freely moving, chronically cannulated male rats were given 10 micrograms of either hpGRF-44 or rhGRF, iv, during peak (1100 h) and trough (1300 h) periods of the GH rhythm. Six-hour plasma GH profiles were obtained after pretreatment with either SRIF AS or normal sheep serum (NSS) as a control. In NSS-treated rats, the plasma GH responses to both hpGRF-44 and rhGRF were significantly greater when the peptides were administered during peak than during trough periods. Immunoneutralization with SRIF AS eliminated these differences and permitted marked GH release in response to both peptides at 1300 h. In addition, SRIF AS augmented the GRF-induced GH response at 1100 h compared with that in NSS controls. The rhGRF peptide caused significantly more GH release than hpGRF under both conditions. These results demonstrate that 1) the GH-releasing abilities of the GRF peptides vary markedly according to the time of injection; 2) the weak GRF-induced GH response observed during trough periods of the GH rhythm is due to antagonization by endogenous circulating SRIF; and 3) the rat-derived GRF may be a more potent GH secretagogue than the human-derived peptide in the rat. The findings reported here together with the available evidence provide support for the hypothesis that GRF and SRIF are secreted tonically from the hypothalamus into the hypophyseal portal blood, and that superimposed upon this steady state release is an additional 3- to 4-h rhythmic surge of each peptide, providing for integration of the ultradian rhythm of GH secretion, as observed in peripheral blood.
Similar articles
-
Sexual dimorphism of somatostatin and growth hormone-releasing factor signaling in the control of pulsatile growth hormone secretion in the rat.Endocrinology. 1991 Jun;128(6):2858-66. doi: 10.1210/endo-128-6-2858. Endocrinology. 1991. PMID: 1674685
-
Time-dependent reduction and potentiation of growth hormone (GH) responsiveness to GH-releasing factor induced by exogenous GH: role for somatostatin.Endocrinology. 1992 Apr;130(4):1822-8. doi: 10.1210/endo.130.4.1347739. Endocrinology. 1992. PMID: 1347739
-
Mechanisms of impaired growth hormone secretion in genetically obese Zucker rats: roles of growth hormone-releasing factor and somatostatin.Endocrinology. 1990 Dec;127(6):3087-95. doi: 10.1210/endo-127-6-3087. Endocrinology. 1990. PMID: 1979030
-
Somatostatin as a physiological regulator of pulsatile growth hormone secretion.Horm Res. 1988;29(2-3):70-4. doi: 10.1159/000180971. Horm Res. 1988. PMID: 2900199 Review.
-
Sexual dimorphism in the control of growth hormone secretion.Endocr Rev. 1985 Spring;6(2):128-50. doi: 10.1210/edrv-6-2-128. Endocr Rev. 1985. PMID: 2861084 Review.
Cited by
-
Ghrelin- and GH-induced insulin resistance: no association with retinol-binding protein-4.Endocr Connect. 2013 May 21;2(2):96-103. doi: 10.1530/EC-13-0019. Print 2013 Jun 1. Endocr Connect. 2013. PMID: 23781325 Free PMC article.
-
Circulating somatomedin-C levels and the effect of growth hormone-releasing factor on plasma levels of growth hormone and somatostatin-like immunoreactivity in obese children.Eur J Pediatr. 1987 Jan;146(1):48-50. doi: 10.1007/BF00647283. Eur J Pediatr. 1987. PMID: 2884108
-
Regulated resurfacing of a somatostatin receptor storage compartment fine-tunes pituitary secretion.J Cell Biol. 2020 Jan 6;219(1):e201904054. doi: 10.1083/jcb.201904054. J Cell Biol. 2020. PMID: 31825461 Free PMC article.
-
Growth hormone releasing hormone or growth hormone treatment in growth hormone insufficiency?Arch Dis Child. 1988 Jun;63(6):629-34. doi: 10.1136/adc.63.6.629. Arch Dis Child. 1988. PMID: 2898924 Free PMC article.
-
Measurement of growth hormone-releasing hormone and somatostatin in hypothalamic-portal plasma of unanesthetized sheep. Spontaneous secretion and response to insulin-induced hypoglycemia.J Clin Invest. 1990 Jul;86(1):17-24. doi: 10.1172/JCI114681. J Clin Invest. 1990. PMID: 1973173 Free PMC article.
Publication types
MeSH terms
Substances
Grants and funding
LinkOut - more resources
Full Text Sources
Other Literature Sources
Research Materials
Miscellaneous