Expression of sex hormone-binding globulin exon VII splicing variant mRNA in human uterine endometrium

We have demonstrated the expression of sex hormone-binding globulin (SHBG) exon VII splicing variant mRNA in human uterine endometrium, using the reverse transcription-polymerase chain reaction-Southern blot and DNA sequencing analyses. Analysis of the missing base pairs corresponded to the entire exon VII, which are considered to encode a portion of the steroid-binding site. Therefore, the steroid-binding affinity of this variant might be different from that of the SHBG wild type. In uterine endometria, the wild-type and variant mRNA levels tended to increase with the advance of the menstrual phase, but the ratio of the SHBG variant mRNA to SHBG wild-type mRNA levels showed no significant difference during the menstrual cycle. So far, there are no indications that the SHBG variant has any biological or clinical implications in human uterine endometrium.