title: Circadian variations of the response of plasma prolactin to brief exposure to ether in the male rat.
abstract: Male adult rats, supplied with an indwelling chronic intrajugular cannula, were exposed to ether for 1 min at various times of the day. Blood samples were taken before and at regular intervals during 1 h following the ether exposure. Basal plasma prolactin showed a circadian variation. The highest level occurred at 1.00 h, and the lowest values were measured at 10.00 and 13.00 h, while a significant increase was observed at 16.00 h compared to the level at 10.00 and 13.00 h. At all times of the day studied exposure for 1 min to ether increased plasma prolactin for at least 30 min and the magnitude of this response to ether varied with the time of day. At 1.00 h the greatest response was observed, while at 10.00 and 13.00 h the most moderate response was measured. The data indicate that there is either a circadian rhythm in basal prolactin, which may cause a significant circadian variation in the magnitude of the stress response, or there is over the 24 h period a significant variation in stress-sensitivity of the hormone, which may contribute to the circadian variation of 'basal' prolactin.
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D004986:Ether / Q000494:pharmacology*; D005019:Ethyl Ethers / Q000494:pharmacology*; D005260:Female; D008297:Male; D011388:Prolactin / Q000097:blood*; D051381:Rats; D013312:Stress, Physiological
chemical_list: D005019:Ethyl Ethers; D004986:Ether; D011388:Prolactin