Changes in testicular transferrin concentrations measured by enzyme immunoassay after FSH administration to beagle dogs

A sensitive enzyme immunoassay (EIA) was developed for transferrin (Tf) in the canine testis, as an effective marker of Sertoli cell function. Tf was purified from male dog serum by DEAE-Affi-Gel Blue chromatography and gel f iltration. Rabbits were immunized with the Tf, and anti-dog Tf antibody was purified from the rabbit serum by affinity chromatography as primary antib ody for EIA. Peroxidase-conjugated goat antidog Tf antibody was used as the secondary antibody for microtitre plate double-antibody EIA. The EIA was a pplied to measurement of testicular Tf concentrations in five normal beagle dogs. All of the dogs were given five injections of 2 mg porcine pituitary FSH at 12 h intervals, and testicular biopsy was performed. The testicular tissue was used for EIA of Tf. The optimum dilutions of the primary and se condary antibodies for the standard curves of canine Tf were 1:4000 and 1:1 000, respectively. The limits of sensitivity of our EIA were between 30 ng Tf/plate-well and 2500 ng/well. The intra- and inter-assay coefficients of variation, and the recovery rate were 8.6, 7.6 and 86.0%, respectively. Bef ore FSH administration, the mean +/-SEM Tf concentration in the testis of n ormal dogs was 357 +/- 31 ng/mL. At 12 h after the final FSH administration , Tf concentrations were significantly increased (p < 0.5) when compared wi th values before the start of treatment. Thus, Tf in the canine testis, mea sured by our EIA, appears capable of serving as a marker of Sertoli cell fu nction.