Changes in intraovarian arterial blood flow were monitored by means of colour-coded and pulsed Doppler ultrasonography in Beagle bitches during the normal oestrous cycle (n = 11) and pregnancy (n = 3), and at PGF(2alpha)-induced luteolysis (n = 4). The ultrasonographic findings were related to the reproductive stage of the bitch, as determined by vaginoscopical and cytological criteria, and by ...

The present study was designed to construct reliable daily salivary progesterone profiles throughout the luteal phase to accurately evaluate the corpus luteum function. Furthermore, we investigated the clinical relevance of a simple midluteal salivary progesterone estimation for the diagnosis of luteal phase insufficiency by determining the diagnostic efficiency and cutoff values. A total of 12...

In the menstrual cycle, extensive angiogenesis accompanies luteinization. During luteolysis, endothelial cells die, whereas in a conceptual cycle, the corpus luteum (CL) persists, and endothelial cell survival is extended. A main stimulator for angiogenesis is vascular endothelial growth factor (VEGF), while the angiopoietins (Ang-1 and Ang-2) may be important modulators. The aim of this study ...

We examined the effects of enclomiphene and zuclomiphene, alone and in combination with oestradiol, on basal and gonadotrophin-stimulated progesterone secretion by isolated subpopulations of both large (granulosa-lutein) and small (theca-lutein) ovine luteal cells. Isolated large and small luteal cells derived from intact, enucleated ovine corpora lutea were incubated for 48-120 h with or witho...

This study compared the responses shown by lactating dairy cows to four different P4-based protocols for AI at estrus. Cows with no estrous signs 96 h after progesterone intravaginal device (PRID) removal were subjected to fixed-time AI (FTAI), and their data were also included in the study. In Experiment I, follicular/luteal and endometrial dynamics were assessed every 12 h from the beginning ...