Central (CSF) and Circulating (serum) Sex Hormones May İnfluence Ocular Surface Temperature in Bitches

This study investigated associations between serum and cerebrospinal fluid (CSF) estradiol (E2) and progesterone (P4) levels and body temperature regulation in thirty clinically healthy bitches. Right and left corneal temperatures (RCT

LCT)

perianal and perivulvar temperatures were measured by infrared thermography

while rectal (RT) and intravaginal temperatures were recorded digitally. Hormone concentrations were determined by enzyme-linked immunosorbent assay (ELISA)

and correlations were analyzed using Pearson’s test. CSF E2 and P4 levels were significantly higher than serum concentrations (p = 0.007 and p = 0.0001). CSF E2 showed a moderate positive correlation with LCT (r = 0.423

p = 0.041)

and CSF P4 was similarly correlated with LCT (r = 0.347

p = 0.035). In contrast

serum P4 was negatively correlated with LCT (r = −0.341

p = 0.039) and RT (r = −0.423

p = 0.009). Perianal temperature demonstrated the strongest association with corneal temperatures

particularly RCT (r = 0.621

p < 0.001). CSF E2 and P4 were strongly correlated (r = 0.640

p < 0.001). These findings suggest that central sex hormones may play a more prominent role than peripheral hormones in ocular surface and regional thermoregulation in bitches Keywords: Dog

estradiol

progesterone

cerebrospinal fluid

corneal surface temperature.