Effects of parachlorophenylalanine, quipazine and cyproheptadine on growth hormone and adrenocorticotropin secretion in steers

Title
Effects of parachlorophenylalanine, quipazine and cyproheptadine on growth hormone and adrenocorticotropin secretion in steers
Publication Date
1987
Author(s)
Sartin, JL
Kemppainen, RJ
Marple, DN
Carnes, R
Dieberg, Gudrun
( author )
OrcID: https://orcid.org/0000-0001-7191-182X
Email: gdieberg@une.edu.au
UNE Id une-id:gdieberg
Oliver, EH
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Elsevier Inc
Place of publication
United States of America
DOI
10.1016/0739-7240(87)90036-1
UNE publication id
une:10716
Abstract
Adrenergic and perhaps dopaminergic neurons provide inhibitory regulation of growth hormone (GH) secretion in ruminants. This suggests that either serotonergic or other neurons regulate the stimulatory release of GH. The nature of neurotransmitter control of adrenocorticotropin (ACTH) secretion in ruminants has not been determined. Parachlorophenylalanine (PCPA; serotonin synthesis inhibitor), quipazine (serotonin receptor agonist) and cyproheptadine (serotonin receptor antagonist) were utilized in Holstein steers to determine whether serotonin receptors mediate stimulatory actions on GH and ACTH secretion. PCPA (100 mg/kg BW) administered each day at 1900 hr for three successive days did not alter mean GH concentrations, amplitude of GH peaks, nor the number of GH peaks. Likewise, PCPA altered none of these parameters for ACTH. Quipazine injected iv at .1 or .5 mg/kg BW increased plasma GH (P<.05) and ACTH (P<.001) concentrations. There was a dose effect of quipazine on both GH (P<.05) and ACTH (P<.001) secretion. Pretreatment of steers with cyproheptadine (.06 and .6 mg/kg BW) reduced the stimulation of GH by quipazine (P<.0001) and decreased basal GH concentrations (P<.0004). Cyproheptadine at .06 mg/kg BW did not alter quipazineeffects on ACTH, however, the higher dose decreased the peak ACTH response (P<.02) to quipazine. Studies with quipazine and cyproheptadine indicated that serotonergic mechanisms are likely involved in the regulation of GH and ACTH secretion in steers.
Link
Citation
Domestic Animal Endocrinology, 4(1), p. 33-41
ISSN
1879-0054
0739-7240
Start page
33
End page
41

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