Pituitary and Plasma LH in Male Fetal Rats
Fetal pituitary LH was undetectable on E15.5, whereas it was 3.25 pg/gland on El6.5 and increased thereafter significantly with fetal age (Fig. 1). The fetal plasma concentration of LH was very low on E17.5 (0.005 ± 0.001 |xg/ L), and it increased marginally on El8.5 and El9.5. There was a significant increase in the LH concentration only between E19.5 and E20.5, from 0.010 ± 0.002 |xg/L to 0.043 ± 0.01 |xg/L (p < 0.001). The sex difference in plasma LH concentrations (females 1.8-fold higher than males) was statistically significant from E19.5 onward (data not shown).
FIG. 1. Pituitary and plasma (serum) concentrations of LH and testicular contents of testosterone (T) in male rat fetuses. The values are mean ± SEM of 7-10 samples. Individual samples were analyzed of all pituitary samples and plasma of Days E20.5 and E21.5. The plasma samples of E17.5-E19.5 were pooled from 2-4 fetuses. Each testicular testosterone content was measured from a pool of two pairs of testes. * Significant difference from the previous age group (*p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001).
LH(3 Subunit Gene Expression
In order to identify the exact onset of LH$ subunit gene expression, LH(3 mRNA in fetal pituitaries was measured by RT-PCR. To ascertain the specificity of the cDNA fragments, the RT-PCR products were transferred onto nylon membranes and subjected to Southern hybridization with a nested cDNA probe. The cDNA fragment with the expected 247-base pair (bp) size was not found on E15.5, but it was faintly detectable on E16.5, and a clear message was found from El7.5 onward, together with a smaller transcript (120 bp) (Fig. 2). The latter was possibly due to alternative splicing, but its exact sequence was not studied. ventolin inhaler
FIG. 2. Southern hybridization analysis of the RT-PCR products of LHfS-subunit transcripts in the fetal rat pituitary of El 5.5-El 8.5 and in adult pituitary. The migration of the expected cDNA products (247 and 120 bp) is depicted on the right of the panel.