New insight on the role of melatonin receptors in reproductive processes of seasonal breeders on the example of mature male European bison (Bison bonasus, Linnaeus 1758).

Melatonin receptors (MT1 and MT2) were shown to regulate proper functioning of reproductive system, especially in seasonally breeding animals. European bison is a unique endangered seasonal breeder and knowledge of the molecular mechanisms of its reproduction is crucial for the survival of the species. The aim of this study was to assess gene expression, protein synthesis and immunohistochemical localization of MT1 and MT2 receptors in testicular and spermatic cord vessels tissues collected in pre-rut (June) and post-rut (December) seasons from adult male European bisons in Bialowieza National Park.

Retinal venous blood carbon monoxide response to bright light in male pigs: A preliminary study.

The physical mechanism by which light is absorbed in the eye and has antidepressant and energizing effects in Seasonal Affective Disorder and other forms of psychiatric major depression is of scientific interest. This study was designed to explore one specific aspect of a proposed humoral phototransduction mechanism, namely that carbon monoxide (CO) levels increase in retinal venous blood in response to bright light. Eleven mature male pigs approximately six months of age were kept for 7days in darkness and fasted for 12h prior to surgery.

Retrograde and destination transfer of sex steroid hormones in the spermatic cord vessels of the mature boar (Sus scrofa) in short-daylight and long-daylight periods, as well as vernal and autumnal equinox.

The aim of this study was to examine the seasonal changes in concentration of steroid hormones in the spermatic cord vessels of the mature boar. Cytochrome P450 aromatase (P450arom) was also localized in the arteries and veins of the spermatic cord. Arterial blood was collected from the common carotid artery and from two branches of the testicular artery supplying the testis and epididymis to determine progesterone (P4), androstenedione (A2), testosterone (T2) and estradiol (E2) plasma concentrations.