J. Gromadzka-ostrowska et al., Twenty-four hour changes in androgens, cortisol and prolactin concentrations in primitive Asiatic pigs, J ANIM FEED, 8(4), 1999, pp. 557-567
Twenty-four h changes in plasma concentrations of cortisol, prolactin and a
ndrogens in both sexes of primitive Asiatic pigs (Vietnamese - Sits scrofa
vittatus) were investigated. Blood samples were drawn from indwelling femor
al artery catheters and plasma concentrations of hormones were analysed by
radioimmunoassay.
All three investigated hormones showed statistically significant 24 h chang
es in boars with higher levels in the morning (cortisol, prolactin, and and
rogens) and in the early (prolactin) or late (cortisol) evening. Patterns o
f plasma cortisol and prolactin concentrations in gilts were the same as in
boars, whereas androgen concentrations in gilts were not changed. The boar
s' androgens showed 24 h changes but without a consistent circadian rhythm.
Only plasma cortisol concentrations in boars as well as in gills had a circ
adian rhythm with the following cosine curve characteristics for boars and
gills, respectively: acrophases (point of 24 h with maximal hormone value)
9.24+/-5.23 h, 7.37+/-3.06 h; amplitudes 1.70+/-1.07, 2.25+/-1.67 ng/ml and
24 h means 9.20+/-0.72 and 7.05+/-0.68 ng/ml.