Plasma relaxin immunoactivity in the pig at parturition and during nuzzling and suckling.
One sow bled at 30--60-min intervals for 48 h at 5 and 4 days before parturition had mean +/- s.e.m. relaxin levels of 5.0 +/- 0.48 ng/ml and 5.5 +/- 0.44 ng/ml for each 24-h period respectively. This sow and another were bled at frequent intervals during parturition; both showed considerable fluctuations in their relaxin levels but no consistent peaks in relation to each birth. Mean levels during parturition were 10.7 +/- 0.46 ng/ml and 13.4 +/- 0.81 ng/ml respectively, both significantly higher than the levels at 4 and 5 days before birth. Relaxin levels in two lactating sows rose acutely during nursing, showing a 3-fold rise in one animal and an 8-fold rise in the other. Results from a third sow during an extended period of nuzzling and sucking by the piglets showed multiple peaks of relaxin immunoactivity associated with each nuzzling/sucking stimulus.
D000818:Animals; D000833:Animals, Suckling; D005260:Female; D007743:Labor, Obstetric; D007774:Lactation; D049590:Postpartum Period; D011247:Pregnancy; D011863:Radioimmunoassay; D012065:Relaxin / Q000097:blood* / Q000378:metabolism; D013552:Swine / Q000097:blood*
D012065:Relaxin