Evidence that changes in LH pulse frequency may regulate the seasonal modulation of LH secretion in ovariectomized mares

in Reproduction
Authors:
B. P. Fitzgerald
Search for other papers by B. P. Fitzgerald in
Current site
Google Scholar
PubMed
Close
,
Helen I'Anson
Search for other papers by Helen I'Anson in
Current site
Google Scholar
PubMed
Close
,
R. G. Loy
Search for other papers by R. G. Loy in
Current site
Google Scholar
PubMed
Close
, and
Sandra J. Legan
Search for other papers by Sandra J. Legan in
Current site
Google Scholar
PubMed
Close
Free access

Sign up for journal news

Summary. To determine whether tonic LH secretion in ovariectomized mares is characterized by pulsatile release, frequent blood samples (every 15 min) were collected from 5 ovariectomized horse mares in nine 8-h periods between February and May. Mean serum LH concentrations increased 9-fold and were associated with a 4-fold increase in mean LH pulse frequency. These results provide the first evidence of pulsatile LH release in ovariectomized mares and suggest that the increasing daylengths of the spring months may increase serum LH by increasing LH pulse frequency.

 

  • Collapse
  • Expand