Analysis of the ratio of biological to immunological LH secreted during the oestrogen-induced LH surge in the ewe

in Journal of Endocrinology
Authors:
I. J. Clarke
Search for other papers by I. J. Clarke in
Current site
Google Scholar
PubMed
Close
,
L. M. Foulds
Search for other papers by L. M. Foulds in
Current site
Google Scholar
PubMed
Close
,
S. Hayward
Search for other papers by S. Hayward in
Current site
Google Scholar
PubMed
Close
,
J. T. Cummins
Search for other papers by J. T. Cummins in
Current site
Google Scholar
PubMed
Close
, and
D. M. Robertson
Search for other papers by D. M. Robertson in
Current site
Google Scholar
PubMed
Close
Restricted access
Rent on DeepDyve

Sign up for journal news

ABSTRACT

Plasma concentrations of in-vitro biological and immunological LH were measured throughout the LH surge in cyclic ewes and in ovariectomized ewes treated i.m. with oestradiol benzoate. Both activities increased in parallel during the LH surge in both groups, although the ratio of biological to immunological activities (B/I ratio) was highest at the peak of the LH surge. The two activities were highly correlated (r = 0·86–0·92), with similar slopes from their regression analysis for the cyclic and ovariectomized groups (1·15 and 1·16 respectively). However, the intercepts of the regression lines did not pass through the origin, but intersected the y (radio-immunoassay) axis, suggesting that these serum samples contained immunoactivity not associated with LH bioactivity. In conclusion, an increase in the LH B/I ratio was observed during the LH surge in oestrogen-treated ovariectomized ewes and in cyclic ewes. This increase was not attributable to a change in the relationship between these two LH activities during the LH surge, but rather to the detection of bioinactive immunoactive material in plasma of unknown composition.

Journal of Endocrinology (1990) 127, 217–222

 

  • Collapse
  • Expand