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The local transfer of testosterone (T) and immunolocalization of cytochrome P450 aromatase (P450arom) in the spermatic cord vessels of ten male wild boar × domestic pig hybrids were examined in December (short-daylight period) and June (long-daylight period). Total T concentration was determined in the jugular vein (JV) and free T concentration was estimated in the common carotid artery (CA), branches of the testicular artery supplying the testis (TA) and epididymis (EA), as well as in testicular veins draining blood from the testis (TV) and spermatic cord (SV). P450arom was immunolocalized in the arterial and venous vessels of the spermatic cord. The concentrations of total T in the JV and free T in the CA did not differ between the examined periods. However, in December, free T concentrations in the TA and EA were higher (p < 0.01–0.001) than in the CA. In June, free T concentration was higher (p < 0.01) in EA than in CA and TA. The concentrations of free T in the TV and SV were higher (p < 0.001) than in the JV regardless of the period. Also, free T concentration in the SV was higher (p < 0.05) in June than in December. P450arom was expressed in all layers of the arterial and venous vessels of the spermatic cord. In June, the intensity of the P450arom staining was higher than in December. The results suggest that the local supply of the male reproductive organs with steroid hormones operate in the hybrids of wild boar × domestic pig. This supply includes the local transfer of testosterone and the P450arom action.

The distribution of androgen receptor (AR) and cytochrome P450 aromatase was investigated in paraffin sections of pregnant pig ovary. Ovarian follicles and corpora lutea were isolated from ovaries obtained on Days 10, 18, 32, 71 and 90 post coitum (p.c.). Androgen receptor was localized in the nuclei of granulosa cells of follicles of various sizes. In addition, some follicles demonstrated staining in the nuclei of theca interna cells. Stroma cells also exhibited a positive immunostaining. At early and mid pregnancy (up to Day 71) AR was expressed in the nuclei of luteal cells. Corpora lutea of Day 71 showed mainly cytoplasmic staining while on Day 90 almost all luteal cells showed staining exclusively in the cytoplasm. Immuno-staining for the presence of cytochrome P450 aromatase was very faint in all investigated ovarian structures. The results could suggest that the process of androgen aromatization plays a negligible role in the ovary of the pregnant pig.

a b s t r a c t In pigs, primordial to primary follicle transition occur in the late pregnancy. The interac- tions between Kit ligand (KL) and its receptor (c-Kit), as well as insulin-like growth factor 1 (IGF1) and cognate receptor (IGF1R) are crucial for the primordial follicle activation. It is well established that hormonal disruption induces abnormalities in the developing repro- ductive system. Hence, this study investigated the influence of antiandrogen, flutamide, on genes involved in the primordial to primary follicle transition. Pregnant gilts were injected with flutamide (50 mg/kg bw, seven times, every day) or corn oil (control groups) start- ing on gestation days 83 (GD90) or 101 (GD108). Fetal ovaries were excised on days 90 and 108 of gestation. The proportion of primordial and primary follicles was determined, and immunohistochemistry for c-Kit and IGF1R was conducted. To assess KL, c-Kit, IGF1 and IGF1R mRNA expression real-time PCR was performed. Ovaries from both GD90 and GD108 animals exhibited a greater proportion of primordial to primary follicles when compared to respective control groups. C-Kit and IGF1R were immunolocalized in the oocytes of pri- mordial and primary follicles. Both c-Kit mRNA and protein levels and KL mRNA expression were diminished in GD90 group. IGF1R expression decreased at mRNA and protein levels, whereas IGF1 mRNA expression was increased in GD90 and GD108 groups. In summary, our findings may indicate that the interactions between KL and c-Kit as well as IGF1 and IGF1R are relevant to the initiation of follicular transition from primordial into primary follicles and can be affected by AR signaling.