Effects of 2-buten-4-olide, an endogenous feeding suppressant, on the pulsatile secretion of luteinizing hormone in ovariectomized rats.
The effects of 2-buten-4-olide (2-B40), an endogenous feeding suppressant, on the secretion of luteinizing hormone (LH) were studied in ovariectomized rats. Intraperitoneal (ip) administration of 2-B40: adult female ovariectomized Wistar rats were given daily ip injections of solution containing 2-B40 at 0, 50 or 100 mg/kg body wt for 14 days. This ip treatment with 2-B40 significantly decreased the mean LH concentration and pulse frequency of LH. Intravenous (iv) administration of 2-B40: a solution of 2-B40 (50 or 100 mg/kg body wt) was slowly injected through an intra-atrium catheter and blood samples were taken every 6 min for 2 h. This iv treatment significantly suppressed the LH pulse frequency but had no significant effect on the LH amplitude or mean LH. Injection of 2-B40 into the third cerebroventricle: the injection of 2-B40 into the third cerebroventricle of freely moving rats decreased the mean LH concentration and the frequency and amplitude of LH pulses. Third cerebroventricle injection of a corticotropin-releasing factor (CRF) receptor antagonist before third cerebroventricle injection of 2-B40: the specific CRF receptor antagonist alpha-helical-CRF (9-41) was injected into the third cerebroventricle of ovariectomized rats before injection of 2-B40. Administration of 2-B40 into the third cerebroventricle significantly decreased the mean LH, concentration and pulse frequency. Third cerebroventricle injection of the CRF antagonist at 50 micrograms/rat and then 2-B40 also resulted in significant suppression of the mean LH concentration and pulse frequency.(ABSTRACT TRUNCATED AT 250 WORDS)
Saito
S
S
Department of Obstetrics and Gynecology, University of Tokushima, School of Medicine, Tokushima, Japan.
Shitsukawa
K
K
Irahara
M
M
Matsuzaki
T
T
Aono
T
T
D015107:4-Butyrolactone / Q000031:analogs & derivatives; D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000494:pharmacology / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005663:Furans / Q000008:administration & dosage / Q000494:pharmacology*; D007274:Injections, Intraperitoneal; D007275:Injections, Intravenous; D007276:Injections, Intraventricular; D007986:Luteinizing Hormone / Q000378:metabolism*; D010052:Ovariectomy; D010446:Peptide Fragments / Q000494:pharmacology; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D005663:Furans; D010446:Peptide Fragments; C004511:butenolide; D007986:Luteinizing Hormone; D003346:Corticotropin-Releasing Hormone; C045089:corticotropin releasing hormone (9-41); D015107:4-Butyrolactone