Denervation of the porcine ovaries performed during the early luteal phase influenced morphology and function of the gonad

We studied both morphology and steroidogenic activity of ovaries in gilts after bilateral surgical denervation performed on day 3 of the estrous cycle. Blood samples were collected from day 4 of the first estrous cycle to day 11 of the subsequent cycle. Denervation resulted in a dramatic reduction in the number or in the disappearance of tyrosine hydroxylase/dopamine-beta-hydroxylase- and/or neuropeptide Y-immunoreactive nerve fibres. On day 11 of the second cycle, the number of follicles (3-6 mm in diameter) was lower (p<0.001) in the denervated ovaries, while corpora lutea were not present. Neurectomy also led to a decrease in the concentrations of progesterone, androstendione and 17beta-estradiol in the follicular fluid originated from small (1-3 mm in diameter) as well as medium-sized follicles (3-6 mm in diameter). Similar to follicular fluid, concentration of androstendione in the follicular wall of medium-sized follicles decreased in experimental gilts in comparison to that of control animals. In addition, plasma concentrations of LH and steroid hormones were lower in the control than in the experimental group. Our results show that denervation of ovaries during the early luteal phase of the estrous cycle in gilts resulted in the changes in both morphology and steroidogenic activity. These results confirm the important role of the peripheral nerves in the function of ovaries.