Implications for the offspring of circulating factors involved in beta cell adaptation in pregnancy. (16th October 2014)

• Record Type: Journal Article
• Authors: Nalla, Amarnadh; Ringholm, Lene; Søstrup, Brigitte; Højrup, Peter; Thim, Lars; Levery, Steven B.; Vakhrushev, Sergey Y.; Billestrup, Nils; Mathiesen, Elisabeth R.; Damm, Peter; Nielsen, Jens H.
• Is Part Of: Acta obstetricia et gynecologica Scandinavica. Volume 93:Number 11(2014)
• Page Start: 1181
• Page End: 1189
• Publication Date: 2014-10-16
• Subjects: Gynecology -- Periodicals; Pregnancy -- Periodicals; Obstetrics -- Periodicals; 618.05
• DOI: 10.1111/aogs.12505
• Languages: English
• ISSNs: 0001-6349

Abstract

<abstract abstract-type="main" id="aogs12505-abs-0001"> <title>Abstract</title> <sec id="aogs12505-sec-0001" sec-type="section"> <title>Objective</title> <p>Several studies have shown an increase in beta cell mass during pregnancy. Somatolactogenic hormones are known to stimulate the proliferation of existing beta cells in rodents whereas the mechanism in humans is still unclear. We hypothesize that in addition to somatolactogenic hormones there are other circulating factors involved in beta cell adaptation to pregnancy. This study aimed at screening for potential pregnancy‐associated circulating beta cell growth factors.</p> </sec> <sec id="aogs12505-sec-0002" sec-type="section"> <title>Samples</title> <p>Serum samples from nonpregnant and pregnant women.</p> </sec> <sec id="aogs12505-sec-0003" sec-type="section"> <title>Methods</title> <p>The effect of serum from pregnant women on the proliferation of rat beta cells was studied using [<sup>3</sup>H]thymidine incorporation and 5‐ethynyl‐2′‐deoxyuridine proliferation assays. In addition, serum from pregnant and nonpregnant women was fractionated by gel filtration and high performance liquid chromatography. The fractionated serum was screened for mitogenic activity in INS‐1E cells. Proteins and peptides in mitogenic active serum fractions were identified by amino acid sequencing and mass spectrometry.</p> </sec> <sec id="aogs12505-sec-0004" sec-type="section"> <title>Main outcome measures</title> <p>Presence of circulating beta cell proliferating factors.</p> </sec> <sec id="aogs12505-sec-0005" sec-type="section"> <title>Results</title> <p>Late gestational pregnancy serum significantly increased proliferation of rat beta cells compared with early pregnancy and nonpregnancy. The mitogenic active serum fractions contained proteins and peptides derived from kininogen‐1, fibrinogen‐α, α1‐antitrypsin, apolipoprotein‐A1, placental lactogen, angiotensinogen and serum albumin.</p> </sec> <sec id="aogs12505-sec-0006" sec-type="section"> <title>Conclusion</title> <p>Pregnancy serum is able to stimulate proliferation of rat beta cells. We have identified several circulating factors that may contribute to beta cell adaptation to pregnancy. Further studies are needed to elucidate their possible role in glucose homeostasis in the mother and her offspring.</p> </sec> </abstract>