Plasma thyrotropin concentration in the male pig: profile from birth to puberty and the effect of season and social environment in the young adult.
Plasma thyrotropin (TSH) secretion was studied in crossbred (Landrace x Large White) immature and young adult Landrace male pigs. Levels of TSH were low over the first 9 wk post-natally and were maximal at 12 wk of age. Thereafter, hormone levels declined and by 16 wk returned to values similar to those at 7 wk. In addition, a transient increase in TSH was noted at 22 wk. A second experiment involved 2 groups of young adult boars housed either in a socially non-restrictive environment (adjacent to estrual females) or a socially restrictive environment (not in direct physical contact with females). TRH stimulated secretion of TSH and the magnitude of this response was affected by month; minimum and maximum responses were found in May and August respectively. There was an effect of social environment on TRH-induced TSH secretion; during February and August, the magnitude of the TSH response to TRH was lower in socially restricted than in socially non-restricted boars.
Trudeau
V L
VL
Department of Functional Morphology, University of Utrecht, The Netherlands.
Meijer
J C
JC
Vandalem
J L
JL
Sanford
L M
LM
D000375:Aging / Q000097:blood; D000818:Animals; D000831:Animals, Newborn / Q000097:blood*; D008297:Male; D012621:Seasons; D012741:Sexual Maturation / Q000502:physiology*; D012931:Social Environment; D013552:Swine / Q000097:blood* / Q000254:growth & development; D013972:Thyrotropin / Q000097:blood*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology
D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin