Serotonin involvement in the inhibition of luteinizing hormone (LH) release induced by prostaglandin D2 (PGD2) in castrated male rats.
p-Chlorophenylalanine (PCPA, 320 mg/kg i.p.), an inhibitor of serotonin (5-HT) synthesis, and 5,6-dihydroxy-tryptamine (5,6-DHT, 50 micrograms i.c.v.), a drug toxic to the indoleaminergic system were used to test the involvement of 5-HT in the mediation of the inhibitory effect of prostaglandin D2 (PGD2) on luteinizing hormone (LH) release in castrated male rats. The i.c.v. administration of PGD2 suppressed the episodic LH release characteristic of castrated rats and decreased mean plasma LH levels and mean LH pulse amplitude significantly. Pretreatment with PCPA or 5,6-DHT apparently eliminated the inhibitory effect of PGD2 on LH secretion. These results suggest the possible involvement of a serotonergic mechanism in the mediation of the suppression of LH secretion induced by PGD2 in castrated male rats.
Koh
T
T
Department of Medicine, Kyoto University School of Medicine, Japan.
Nakai
Y
Y
Kinoshita
F
F
Imura
H
H
D015115:5,6-Dihydroxytryptamine / Q000494:pharmacology; D000818:Animals; D010134:Fenclonine / Q000494:pharmacology; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D008297:Male; D009919:Orchiectomy; D015230:Prostaglandin D2; D011457:Prostaglandins D / Q000494:pharmacology*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000502:physiology*
D011457:Prostaglandins D; D012701:Serotonin; D007986:Luteinizing Hormone; D010134:Fenclonine; D015230:Prostaglandin D2; D015115:5,6-Dihydroxytryptamine