The boar testis secretes high amounts of oestrogens. In order to test for a likely local significance, we investigated the expression of oestrogen receptors (ER) in immature and mature boar testes using immunohistochemistry (IHC), in vitro and in situ reverse transcription-polymerase chain reaction (RT-PCR). Samples were from 25 boars castrated at ages of 50, 100, 150, 200 and 250 days. Mouse monoclonal primary antibodies against porcine ERalpha (clone HT227), human ERbeta1 (clone PPG5/10) and human P450 aromatase (clone SM1671P) were used. Expression of the mRNA was tested utilizing primers specific for the respective porcine mRNA sequences. ER immunoreactivity was exclusively localized to the nuclei. In immature boars, 90.6 +/- 1.2% of prespermatogonia and 71.0 +/- 2.6% of the Leydig cells showed a strong staining for ERalpha; 95.5 +/- 3.5% of the prespermatogonia but none of the Leydig and Sertoli cells were ERbeta-positive. In mature boars a strong staining for the ERbeta was observed in virtually all Sertoli, Leydig and germ cells, except for the elongating/ed spermatids, which were clearly negative; for the ERalpha, strong immunoreaction signals were restricted to spermatogonia and primary spermatocytes with 93.6 +/- 2.7% of these cells being positive; distinctly less intensive signals were observed in 51.4 +/- 0.27% of the secondary spermatocytes, round spermatids and Leydig cells. In vitro RT-PCR was positive for both receptors and results of in situ RT-PCR matched those obtained by IHC. P450 aromatase immunoreaction was restricted to the cytoplasm of Leydig cells. These findings suggest that testicular ER may be important factors contributing to onset and maintenance of spermatogenesis in the boar.

No abstract

The provision of biologically active estrogens to the testicular and epididymal compartment is controlled by a complex regulatory system, with the sulphatase pathway being an important component. P is a secretory product of the testis, E1 and E1S are not actively enriched in seminal plasma.

No abstract

Data relating to reproductive parameters of German shepherd bitches were collected from registered German shepherd dog (GSD) breeders with information kept over a 15-year period (1982-1997). The information obtained was verified using the East African Kennel Club records. A total of 594 bitches from 280 breeders were recorded. From these, 798 heats were observed, 594 of which were used for breeding, resulting in 3592 puppies. The mean age at puberty was 519.0 ± 41 days. Heats occurred throughout the year, although significantly (P < 0.05) higher and lower incidences were observed in October and April respectively. Pregnancy significantly (P < 0.01) increased interoestrous interval, which was 247.8 ± 99.6 and 183 ± 52 days among bred/pregnant and non-bred bitches respectively. Most bitches in oestrus (73.7 %) were bred, and breeding was carried out throughout the year, with a distribution closely related to that of heat incidence. Subsequently, whelping occurred throughout the year, and 95.5 %of the bitches that were mated whelped. A mean gestation period of 60.6 ± 5.1 days was observed. The mean litter size was 6.4 ± 0.4 puppies, and did not differ significantly between months. The preweaning losses were low, with 2.3 % stillbirths, 0.9 % culls and 11.4 % mortalities