title: Delta sleep inducing peptide (DSIP) stimulates the release of LH but not FSH via a hypothalamic site of action in the rat.
abstract: Long term ovariectomized (OVX) Sprague-Dawley rats were injected intraventricularly (3rd ventricle) with 5 micrograms (2 microliter) of DSIP. This caused a significant elevation (p = 0.01) of LH levels within 30 min. The values remained elevated for 2 hr; however, FSH levels remained unchanged. The minimal effective dose of DSIP to evoke this effect was 1 microgram. If plasma PH was lowered by pretreatment of the animals with estradiol, the 5 micrograms dose evoked an even greater effect to elevate LH significantly at 30 and 60 min following its intraventricular injection. To determine the site of action of DSIP, dispersed, overnight cultured pituitary cells from OVX rats were incubated with varying concentrations (10(-7) to 10(-12) M) of DSIP in an in vitro system. There was no response to DSIP from the cells in the above system. To evaluate its possible action on the hypothalamus, median eminence (ME) fragments from male rats were incubated in vitro with DSIP in varying concentrations from 10(-7) to 10(-10) M. There was a significant (p less than 0.001) increase in LHRH released from the ME at a concentration of DSIP of 10(-7) M. A sleep-related increase in LH release is seen during puberty in man. It is possible that DSIP released within the hypothalamus may play a physiological role in sleep-related LH release.
mesh_terms: D000818:Animals; D003701:Delta Sleep-Inducing Peptide / Q000494:pharmacology*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D008297:Male; D008473:Median Eminence / Q000378:metabolism; D010052:Ovariectomy; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical
chemical_list: D007987:Gonadotropin-Releasing Hormone; D003701:Delta Sleep-Inducing Peptide; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone