Pituitary prolactin concentrations associated with daily prolactin surges in pseudopregnant rats.
During pseudopregnancy (PSP) two surges of prolactin (PRL) secretion from the pituitary are observed, the nocturnal surge at dawn and the diurnal surge in the evening. An attempt was made to clarify the correlation between changes in serum and pituitary PRL concentrations on day 5-6 of PSP. During the nocturnal surge, pituitary PRL concentration decreased significantly from 0000 hr to 0300-0600 hr. On the other hand, the high pituitary PRL concentration remained unchanged during the diurnal surge from 1200 hr to 1800 hr. These findings suggest that the nocturnal and diurnal PRL surges are regulated by separate controlling mechanisms.
Furudate
S
S
Department of Laboratory Animal Science, Kitasato University School of Medicine, Kanagawa, Japan.
D000818:Animals; D002940:Circadian Rhythm; D005260:Female; D010902:Pituitary Gland / Q000378:metabolism*; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D011555:Pseudopregnancy / Q000503:physiopathology / Q000662:veterinary*; D051381:Rats
D011388:Prolactin