Document Detail

Plasma glucagon and insulin in rat pregnancy. Roles in glucose homeostasis.
MedLine Citation:
PMID:  1109177     Owner:  NLM     Status:  MEDLINE    
To determine if pancreatic glucoregulatory hormones can be implicated in the glucose fall of pregnancy, we have measured plasma immunoreactive insulin and glucagon (IRI and IRG) in rats. Fed rats in midgestation show a rise in IRI without a corresponding increase in IRG. In late gestation, IRG rises significantly, but only enough to keep pace with a further rise in IRI. On a molar basis, IRI remains the predominant hormone despite a marked fall in blood glucose. After a 48-h fast IRI falls to comparably low levels in pregnant and virgin rats. A small rise in IRG is seen in virgin but not in pregnant rats despite frank hypoglycemia in the latter. Thus, IRG secretion in pregnancy is diminished relative to IRI in the fed state and fails to increase in the fasted state despite the stimulus of a lower glucose in both instances. To evaluate IRG secretory reserve, the IRG response to i.v. alanine was assessed in late gestation. In fed rats a greater IRG increase is seen in pregnancy; after fasting no difference is seen between pregnant and virgin rats. These results preclude an absolute deficiency in glucagon secretion. Pancreas hormone stores were alos measured in an effort to explain the altered secretory state. We find reciprocal changes in IRI and IRG content favoring IRG in midgestation and IRI in late gestation. Thus, pancreas hormone storage is altered in pregnancy but does not account for the changes in hormone secretion. Rather, pregnancy exerts an effect on the islet secretory process itself. Release of IRI is enhanced relative to IRG regardless of the blood sugar level. These observations suggest that in the pregnant rat circulating levels of insulin and glucagon may act to limit hepatic glucose output. Available evidence from the literature supports the concept of restrained glucose production. It is proposed that a lower blood glucose production. It is proposed that a lower blood glucose in rat pregnancy may be a lesser liability teleologically than would be the obligate nitrogen wasting which accompanies gluconeogenesis.
C D Saudek; M Finkowski; R H Knopp
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  The Journal of clinical investigation     Volume:  55     ISSN:  0021-9738     ISO Abbreviation:  J. Clin. Invest.     Publication Date:  1975 Jan 
Date Detail:
Created Date:  1975-02-18     Completed Date:  1975-02-18     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7802877     Medline TA:  J Clin Invest     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  180-7     Citation Subset:  AIM; IM    
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MeSH Terms
Alanine / diagnostic use
Antigens / analysis
Blood Glucose / analysis
Glucagon / blood*,  immunology,  physiology
Glucose / metabolism*
Insulin / blood*,  immunology,  physiology
Pancreas / metabolism
Pentobarbital / pharmacology
Pregnancy Trimester, Second
Pregnancy Trimester, Third
Reg. No./Substance:
0/Antigens; 0/Blood Glucose; 11061-68-0/Insulin; 50-99-7/Glucose; 56-41-7/Alanine; 76-74-4/Pentobarbital; 9007-92-5/Glucagon

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

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