Document Detail


Altered release of growth hormone from dispersed adenohypophysial cells of streptozotocin diabetic rats. I. Effects of growth hormone releasing factor and somatostatin.
MedLine Citation:
PMID:  2575447     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
As growth hormone has been implicated in the "dawn phenomenon," an early morning rise in serum glucose, we have studied the control of growth hormone release in diabetes using an acutely dispersed system of adenohypophysial cells from normal or diabetic rats (65 mg/kg streptozotocin, 8 days before sacrifice; serum glucose, 490 +/- 17 mg/dL). Growth hormone release is normally controlled by the two hypothalamic hormones, growth hormone releasing factor and somatostatin. We have found cells of the diabetic rats exhibit changes in sensitivity that result in increased growth hormone release in static incubation. In normal cells, rat growth hormone releasing factor increases growth hormone release three- to four-fold with an EC50 of 151 +/- 27 pM (n = 7). In contrast, in cells from diabetic rats, there was a significant (twofold) increase in sensitivity to growth hormone releasing factor (EC50 = 75 +/- 15 pM, n = 7) which resulted in increased growth hormone release with lower but not maximal (10 nM) growth hormone releasing factor. Basal nonstimulated release was unchanged. Somatostatin inhibition of stimulated growth hormone release was reduced (n = 7); half-maximal inhibition occurred with 0.21 +/- 0.03 nM (normal) and 0.76 +/- 0.17 nM somatostatin (diabetic). In perifusion the peak secretion rate was significantly lower for diabetic cells stimulated by a maximal dose of growth hormone releasing factor. These studies suggest somatotrophs of diabetic rats have altered sensitivity in vitro to the controlling hormones growth hormone releasing factor and somatostatin.
Authors:
M S Sheppard; B A Eatock; R M Bala
Related Documents :
2575447 - Altered release of growth hormone from dispersed adenohypophysial cells of streptozotoc...
17785697 - Metabolic implications of gh treatment in small for gestational age.
19303977 - Serum levels of angiopoietin-related growth factor in diabetes mellitus and chronic hem...
3813637 - Growth and growth factors in diabetes mellitus.
24747137 - The detrimental effects of acute hyperglycemia on myocardial glucose uptake.
21780897 - Current understanding of insulin resistance in hepatitis c.
Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Canadian journal of physiology and pharmacology     Volume:  67     ISSN:  0008-4212     ISO Abbreviation:  Can. J. Physiol. Pharmacol.     Publication Date:  1989 Oct 
Date Detail:
Created Date:  1990-03-09     Completed Date:  1990-03-09     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372712     Medline TA:  Can J Physiol Pharmacol     Country:  CANADA    
Other Details:
Languages:  eng     Pagination:  1315-20     Citation Subset:  IM    
Affiliation:
Department of Medicine, University of Saskatchewan, Saskatoon, Canada.
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Descriptor/Qualifier:
Animals
Diabetes Mellitus, Experimental / metabolism*
Growth Hormone / secretion*
Growth Hormone-Releasing Hormone / pharmacology*
Male
Pituitary Gland, Anterior / cytology,  drug effects,  secretion*
Rats
Rats, Inbred Strains
Somatostatin / pharmacology*
Chemical
Reg. No./Substance:
51110-01-1/Somatostatin; 9002-72-6/Growth Hormone; 9034-39-3/Growth Hormone-Releasing Hormone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


Previous Document:  Effect of ganglionic stimulating and blocking agents on the fast components of colonic myoelectrical...
Next Document:  Hypersexuality with antiparkinsonian therapy.