Late but not early gestational maternal growth hormone treatment increases fetal adiposity in overnourished adolescent sheep.

Full Abstract

In the overnourished adolescent sheep, maternal tissue synthesis is promoted at the expense of placental growth and leads to a major decrease in lamb birth weight at term. Maternal growth hormone (GH) concentrations are attenuated in these pregnancies, and it was recently demonstrated that exogenous GH administration throughout the period of placental proliferation stimulates uteroplacental and fetal development by Day 81 of gestation. The present study aimed to determine whether these effects persist to term and to establish whether GH affects fetal growth and body composition by increasing placental size or by altering maternal metabolism. Adolescent recipient ewes were implanted with singleton embryos on Day 4 postestrus. Three groups of ewes offered a high dietary intake were injected twice daily with recombinant bovine GH from Days 35 to 65 of gestation (high intake plus early GH) or from Days 95 to 125 of gestation (high intake plus late GH) or remained untreated (high intake only). A fourth moderate-intake group acted as optimally nourished controls. Pregnancies were terminated at Day 130 of gestation (6 per group) or were allowed to progress to term (8-10 per group). GH administration elevated maternal plasma concentrations of GH, insulin, glucose, and nonesterified fatty acids during the defined treatment windows, while urea concentrations were decreased. At Day 130, GH treatment had reduced the maternal adiposity score, percentage of fat in the carcass, and internal fat depots and leptin concentrations, predominantly in the high-intake plus late GH group. Placental weight was lower in high-intake vs. control dams but independent of GH treatment. In contrast, fetal weight was elevated by late GH treatment, and these fetuses had higher relative carcass fat content, perirenal fat mass, and liver glycogen concentrations than all other groups. Expression of leptin mRNA in fetal perirenal fat and fetal plasma leptin concentrations were not significantly altered by maternal nutritional intake or GH. In pregnancies proceeding to term, the duration of gestation, fetal placental mass, and lamb birth weight were reduced in high-intake compared with control dams but were not significantly affected by GH treatment. In conclusion, exogenous GH has profound effects on maternal endocrinology, metabolism, and body composition when administered during early and late pregnancy. Treatment during late pregnancy has a modest effect on fetal growth independent of placental size and a profound effect on fetal adiposity, which may have implications beyond the fetal period.

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Author information

Author/s: Wallace, Jacqueline M (JM); Matsuzaki, Masatoshi (M); Milne, John (J); Aitken, Raymond (R);

Affiliation: Rowett Research Institute, Bucksburn, Aberdeen AB21 9SB, United Kingdom. Jacqueline.Wallace(-atsign-)rri.sari.ac.uk

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't

Journal: Biology of reproduction (Biol Reprod), published in United States. (Language: eng)

Reference: 2006-Aug; vol 75 (issue 2) : pp 231-9

Dates: Created 2006/07/24; Completed 2006/12/04; Revised 2008/11/21;

PMID: 16687645, status: MEDLINE (last retrieval date: 12/26/2008)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

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MeSH headings (categories)

This article was linked to the MESH Headings shown below.

Adipose Tissue - drug effects; embryology
Animals
Body Composition
Body Weight - drug effects
Eating
Endocrine System - metabolism
Female
Fetal Development - drug effects
Gestational Age

Gestational Age
Growth Hormone - pharmacology
Leptin - metabolism
Maternal Age
Maternal Nutritional Physiological Phenomena
Placenta - drug effects; growth & development
Pregnancy
Pregnancy Outcome
Sheep

Associated Chemicals: Leptin (0) ; Growth Hormone (9002-72-6)

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