A hypothalamic follicle-stimulating hormone-releasing decapeptide in the rat.
Previous studies indicated that there is a separate hypothalamic control of follicle-stimulating hormone (FSH) release distinct from that of luteinizing hormone (LH). An FSH-releasing factor (FSHRF) was purified from rat and sheep hypothalami, but has not been isolated. We hypothesized that FSHRF might be an analogue of mammalian luteinizing hormone-releasing hormone (m-LHRH) and evaluated the activity of many analogues of m-LHRH and of the known LHRHs found in lower forms. Here we demonstrate that lamprey (l) LHRH-III has a potent, dose-related FSH- but not LH-releasing action on incubated hemipituitaries of male rats. l-LHRH-I on the other hand, had little activity to release either FSH or LH. m-LHRH was equipotent to l-LHRH-III to release FSH, but also had a high potency to release LH in contrast to l-LHRH-III that selectively released FSH. Chicken LHRH-II had considerable potency to release both LH and FSH, but no selectivity in its action. Salmon LHRH had much less potency than the others tested, except for l-LHRH-I, and no selectivity in its action. Because ovariectomized, estrogen, progesterone-treated rats are a sensitive in vivo assay for FSH- and LH-releasing activity, we evaluated l-LHRH-III in this assay and found that it had a completely selective stimulatory effect on FSH release at the two doses tested (10 and 100 pmols). Therefore, l-LHRH-III is a highly potent and specific FSH-releasing peptide that may enhance fertility in animals and humans. It may be the long sought after m-FSHRF.
Yu
W H
WH
Pennington Biomedical Research Center, Louisiana State University, 6400 Perkins Road, Baton Rouge, LA 70808-4124, USA.
Karanth
S
S
Walczewska
A
A
Sower
S A
SA
McCann
S M
SM
D000818:Animals; D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism / Q000502:physiology*; D007987:Gonadotropin-Releasing Hormone / Q000502:physiology; D007031:Hypothalamus / Q000502:physiology*; D008297:Male; D009419:Nerve Tissue Proteins / Q000302:isolation & purification / Q000502:physiology; D010455:Peptides / Q000302:isolation & purification / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D009419:Nerve Tissue Proteins; D010455:Peptides; D007987:Gonadotropin-Releasing Hormone; D005640:Follicle Stimulating Hormone