Catecholamine content and adenylate cyclase activity in corpora lutea of different ages of the PMSG-treated immature rat.
The catecholamine content and adenylate cyclase response were studied in a well-characterized corpus luteum model, where ovulation was induced by treatment of prepubertal Sprague-Dawley rats with pregnant mare's serum gonadotropin. The luteal content of noradrenaline, determined with HPLC, was constant during the first 7 days of pseudopregnancy, followed by a 3-fold increase in older corpora lutea. No detectable amounts of dopamine were found, while trace amounts of adrenaline were found in a few cases. The increase in noradrenaline content was not associated with a changed sensitivity of luteal adenylate cyclase to catecholamines. The response to adrenaline was maximal in 3-day-old corpora lutea, whereafter a decrease was seen. The significance of the increased endogenous levels of noradrenaline at the end of pseudopregnancy is at present unknown. However, the fact that the increase in noradrenaline occurs a few days before spontaneous luteolysis is of special interest, since it has been suggested that an adrenergic innervation is a prerequisite for the antigonadotropic effect of prostaglandin F2 alpha in the human corpus luteum.
Selstam
G
G
Department of Physiology, University of Umeå, Sweden.
Norjavaara
E
E
Rosberg
S
S
Khan
I
I
Hamberger
B
B
Hamberger
L
L
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000375:Aging / Q000378:metabolism; D000818:Animals; D002395:Catecholamines / Q000378:metabolism*; D003338:Corpus Luteum / Q000187:drug effects / Q000378:metabolism*; D004837:Epinephrine / Q000378:metabolism; D005260:Female; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D002395:Catecholamines; D006064:Gonadotropins, Equine; D000262:Adenylyl Cyclases; D009638:Norepinephrine; D004837:Epinephrine