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Selection for growth rate or against back fat thickness in pigs is associated with changes in growth hormone axis plasma protein concentration and mRNA level.

Authors :
te Pas MF
Freriksen JW
van Bijnen AJ
Gerritsen CL
van den Bosch TJ
Harders FH
Verburg FJ
Visscher AH
de Greef KH
Source :
Domestic animal endocrinology [Domest Anim Endocrinol] 2001 Apr; Vol. 20 (3), pp. 165-84.
Publication Year :
2001

Abstract

Selection for increased growth rate or decreased back fat thickness results in concomitant changes in endocrine and metabolic status. Growth hormone (GH) changes in blood plasma concentration related to selection for growth rate and fat deposition were reported in pigs. The molecular mechanisms regulating selection-induced changes in GH plasma concentration remain largely unknown. We investigated selection-associated changes in GH axis parameters in 2 pig lines selected for increased growth rate (F-line), or decreased back fat thickness (L-line), respectively. First, we investigated selection-associated changes in GH pulse parameters. In both selection lines we found each generation a declining GH peak maximum concentration and area under the GH curve. GH pulse width was not associated with generation number. In both lines generation number was associated with a declined pulse interval, indicating that the number of pulses per day increased on average with 1 pulse per 24 h per generation. Second, plasma concentration of GH axis related Insulin-like growth factor-I (IGF-I) and insulin were investigated. Plasma IGF-I concentration was not associated with generation number in the F-line. Mean plasma insulin concentration declined each generation in both lines. Third, we investigated changes in GH and Pit-1 mRNA levels. In both selection lines GH and Pit-1 mRNA levels increased approximately 50% each generation. The high SD of the GH mRNA levels in both lines may suggest that the GH mRNA levels are pulsatile in vivo. We postulate a molecular mechanism that may explain how selection is associated with increased GH mRNA levels and GH pulse numbers, while lowering GH release per pulse.

Details

Language :
English
ISSN :
0739-7240
Volume :
20
Issue :
3
Database :
MEDLINE
Journal :
Domestic animal endocrinology
Publication Type :
Academic Journal
Accession number :
11438399
Full Text :
https://doi.org/10.1016/s0739-7240(01)00094-7