Temporal and other effects of catechol estrogens on prolactin secretion in the rat.
Temporal alterations in plasma prolactin levels caused by the administration of 2-hydroxyestradiol and 2-hydroxyestrone (100 microgram/kg) into the right atrium of freely-moving conscious male rats were examined. The catechol estrogens were given in a single bolus via an indwelling cannula and plasma prolactin concentration was monitored by taking blood samples every 2 min. A pulsatile elevation of plasma prolactin occurred approximately 4 h after the injection of 2-hydroxyestradiol and a small increase was also observed when it was administered to rats bearing a Silastic capsule containing estradiol. 2-Hydroxyestrone had no effect in untreated male rats but produced a 5- to 6-fold elevation in plasma prolactin level 4 h after its administration to rats implanted with estradiol. It is proposed that 2-hydroxyestrone suppresses the action of estradiol on prolactin secretion from the pituitary and that the accumulated hormone is released when the concentration of this catechol estrogen falls below a critical level. A longer latent period was required to produce an elevation in plasma prolactin levels by 2-hydroxyestradiol than by estradiol.
D000818:Animals; D004343:Drug Implants; D004347:Drug Interactions; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology*; D002393:Estrogens, Catechol / Q000494:pharmacology*; D006894:Hydroxyestrones / Q000494:pharmacology; D007700:Kinetics; D008297:Male; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D004343:Drug Implants; D002393:Estrogens, Catechol; D006894:Hydroxyestrones; D004958:Estradiol; D011388:Prolactin; C001390:2-hydroxyestradiol; C024980:2-hydroxyestrone