Abstract:
:Although LHRH can stimulate the release of both LH and FSH from the pituitary, there are a number of instances in which the secretion of LH and FSH are divergent. Previous studies from our laboratory have indicated that pulsatile LH and FSH secretion are independently regulated by gonadal factors. We have, therefore, reexamined the role of LHRH in regulating pulsatile gonadotropin secretion by evaluating the effect of passive LHRH immunoneutralization on LH and FSH secretion in castrate adult male rats. Injection of 500 microliters ovine anti-LHRH serum no. 772 (LHRH-AS) into 2-week-castrate rats caused an 85% suppression of mean plasma LH levels by 2 h, which lasted through 48 h. Mean plasma FSH, however, was reduced by only 19% after 2 h and by only 59% after 48 h. When cannulated 2-week-castrate rats were bled every 10 min, both LH and FSH were secreted in a pulsatile manner. Injection of 500 microliters LHRH-AS caused an immediate abolishment of LH pulses and a rapid reduction in mean plasma LH through 24 h. Pulsatile FSH secretion, as characterized by the parameters of pulse frequency and amplitude, was unaffected by LHRH-AS, although mean plasma FSH levels were significantly reduced. Collectively, the results suggest that pulsatile FSH secretion is regulated by a separate factor(s) distinct from LHRH, but that LHRH is required for the maintenance of elevated FSH levels.
journal_name
Endocrinologyjournal_title
Endocrinologyauthors
Culler MD,Negro-Vilar Adoi
10.1210/endo-118-2-609subject
Has Abstractpub_date
1986-02-01 00:00:00pages
609-12issue
2eissn
0013-7227issn
1945-7170journal_volume
118pub_type
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