Oestradiol-17beta and
testosterone blood plasma concentrations were measured in dogs with Leydig-cell tumours (n=20), Sertoli-cell tumours (n=6),
seminomas (n=9), unilateral
inguinal cryptorchidism (n=7),
abdominal cryptorchidism (n=9, one bilateral), degenerate scrotal testicles (n=6, two bilateral), and animals with normal scrotal testicles (n=20). The
testosterone/
oestradiol ratio (
testosterone concentration [ng/mL]x100/
oestradiol concentration [pg/mL]) was calculated.A considerably higher
oestradiol concentration was found in dogs with Sertoli-cell tumours (29.0, 14.4-48.3 pg/mL; median, minimum-maximum; P=0.0256, Mann-Whitney test) and lower
oestradiol levels were found in animals with
seminomas (12.0, 3.4-17.6 pg/mL; P=0.0025) compared to the healthy control group (18.0, 8.6-31.5 pg/mL).
Testosterone concentration was decreased in dogs with Sertoli-cell tumours (0.08, 0.03-0.77 ng/mL) when compared to the control group (1.95, 0.05-3.70 ng/mL; P=0.0012).
Testosterone/
oestradiol ratios differed from the control (9.6, 0.58-35.8) only in dogs with Sertoli-cell tumours (0.32, 0.06-2.80; P=0.0005). Clinical signs of
feminization were observed in five dogs with Sertoli-cell tumour and one dog with a Leydig-cell tumour, and were more often associated with decreased
testosterone/
oestradiol ratios than with an increased oestradiol-17beta concentration.