Interactions between LH and T have been reported in mammals and birds. LH stimulates T secretion with a time delay of about 10-15 min, and T has a negative feedback on LH secretion. In the present study, concordance between LH and T pulses was 34%, 78%, and 71% at 13, 23, and 35 wk of age, respectively. Most pulses of T were preceded by LH pulses. Some pulses of T were detected without prior or post-pulses of LH, and vice versa. Pulse occurrences between LH and T in this study might reflect this negative feedback relationship: that is, LH stimulates secretion of T without T feedback effects, or the two might change independently, since some LH pulses were not followed by pulses of T or pulses of T were not associated with pulses of LH. ventolin 100 mcg
Concordance rate was higher at 23 wk of age and later, indicating that age rather than reproductive state is associated with concordance of pulses at 35 wk of age. It cannot be concluded that interactions between LH and T exist based on only secretory pattern analysis, because the results from statistical analysis might not really reflect physiological relationships between LH and T secretion. For example, few pulses of T were detected in the SL birds at 35 wk of age in comparison to the number of pulses of LH.