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The efficiency of the retrograde transfer of steroid ovarian hormones from the ovarian effluent into blood supplying the ovary and the rate of its back transport to the ovary were determined for the first time in in vivo conditions. Sexually mature gilts (n = 25) were used in the physiological study. The concentration of oestradiol and progesterone in blood collected from the ovarian artery was higher in both the follicular phase (by 87.9 ± 2.9% and 150.0 ± 4.8%, respectively, P < 0.001) and the luteal phase (by 82.1 ± 3.9% and 77.7 ± 2.7%, respectively, P < 0.001) than in systemic blood reaching the initial part of the ovarian artery. The high efficiency of the retrograde transfer was not dependent on the concentration of hormones in the ovarian venous blood. However, the efficiency and rate of the retrograde transfer differed between phases of the oestrous cycle. We suggest that such effective retrograde transfer of ovarian hormones must affect the secretory function of the ovary. [ABSTRACT FROM AUTHOR]

Investigates the elevation of estrone and androstenedione concentrations in the blood supplying the oviduct and uterus of gilts. Transfer of steroid hormones to the walls of the vessels; Regulation of the uterine blood flow in estrus cycle; Correlation of blood flow with the ratio of estrogens to progesterone.

The nasal venous blood may be directed through the facial vein into the systemic circulation or through the frontal vein into the venous cavernous sinus of the perihypophyseal vascular complex, where hormones and pheromones permeate from the venous blood into the arterial blood supplying the brain and hypophysis. The present study was designed to determine the effect of noradrenaline (NA) on the tension of the nasal, frontal and facial veins of cycling gilts, and influence of ovarian steroid hormones on NA-mediated contractile reactivity. Additionally, the enzyme dopamine-beta-hydroxylase catalysing the conversion of dopamine to noradrenaline (DbetaH) was immunolocalized in these vessels. Among three studied veins, the frontal proximal vein, that fulfill a key role in the supply of the nasal venous blood into the venous cavernous sinus, reacted to NA most strongly (P < 0.001) and this reaction was weaker in the periestrous period than in luteal phase (P < 0.001). Inversely, the reaction to NA of the facial proximal vein, that carry blood to the peripheral circulation, was stronger in the periestrous period than in luteal phase (P < 0.05). P4, E2 and T significantly lowered NA-mediated tension of the frontal proximal vein during the periestrous period (P < 0.001), while in the luteal phase P4 might antagonize relaxing effect of E2 to this vessel. The result suggests that supply of the nasal venous blood into the venous cavernous sinus is greater during the periestrous period than during the luteal phase. DbetaH was clearly expressed in the muscular layer of the isolated superficial nasal and facial veins of gilts in both studied stages of the estrous cycle. We suggest that the reactivity of the superficial veins of the nose and face to NA combined with the previously demonstrated reactivity of these veins to steroid ovarian hormones and male steroid pheromones may regulate the access of priming pheromone androstenol (resorebed in the nasal cavity) to the brain of gilts during periestrous period via humoral local destination transfer.

The aryl hydrocarbon receptor (AhR) has been recognized as a mediator of xenobiotic-induced toxicity. In addition, it was demonstrated that the AhR is able to influence the regulation of reproductive processes in females. The aim of this study was to examine AhR mRNA (real-time PCR) and protein (Western-blot) expression in ovarian follicles and stroma, corpora lutea (CL), oviducts, endometrium, myometrium as well as in medial basal hypothalami (MBH), and anterior (AP) and posterior (PP) pituitaries harvested during the follicular (days 17-19) and luteal (days 8-10) phase of the porcine estrous cycle. The AhR transcript and protein were found in all structures collected during both phases. AhR mRNA expression tended (p=0.06) to be higher in the CL than in follicles. The AhR protein expression in ovarian stroma was higher (p≤0.01) during the follicular than in the luteal phase. Endometrial expression of AhR mRNA was higher (p≤0.01), while AhR protein was lower (p≤0.01) during the follicular phase in comparison to the luteal phase. Within neuroendocrine tissues, AhR mRNA and protein content in hypothalamus were relatively low and did not differ (p>0.05) between phases. In contrast, higher AhR mRNA expression in AP (p≤0.001) and protein expression in PP (p≤0.01) were found during the luteal phase compared to the follicular phase. Differences in AhR expression observed in reproductive and neuroendocrine tissues during the follicular and luteal phase of the estrous cycle indicate the involvement of AhR in the regulation of reproductive function in pigs., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The present study was undertaken to elucidate whether an increased, but physiological, amount of progesterone (P4) supplied to the porcine corpus luteum affects luteal secretion of activin A and inhibin alpha-subunit (Inhalpha) in freely moving gilts. On day 9 of the estrous cycle (EC), both ovarian arteries and both ovarian veins of gilts (n = 5) were cannulated. Progesterone was infused into the right ovarian arteries in gilts on days 10, 11 and 12 of the EC at a rate adequate to its physiological retrograde transfer found during the middle luteal phase of the EC. The P4 infusion rate was 0.62 microg/min (day 10), 2 x 0.62 microg/min (day 11) and 3 x 0.62 microg/min (day 12). The left ovarian arteries were infused with saline (control). Blood samples were collected from both ovarian veins on days 10-12 of the EC before and after P4 or saline infusion. The mean plasma activin A level in the ovarian vein ipsilateral to the P4-infused ovary was higher (P < 0.0001) on days 10-12 of the EC than this found in the contralateral ovarian vein. The level of activin A in the ovarian vein ipsilataral to the infusion of P4 was higher on days 11 (P < 0.01) and 12 (P < 0.0001) and tended to be higher (P < 0.07) on day 10 of the EC than this in contralateral ovarian vein. The level of Inhalpha in the ovarian vein ipsilateral to the P4-infused ovary on days 10-12 of the EC was not significantly different (P > 0.05) than this found in the contralateral ovarian vein. The results of the present study indicate that a local elevation of P4 concentration in blood supplying the ovary during the middle luteal phase of the porcine EC affects ovarian secretion of activin A. The effect of P4 on the secretion of activin A suggested the existence of a short regulatory loop of a positive feedback between P4 being retrogradely transferred into the ovary and the secretion of this peptide.

The present study was undertaken to elucidate whether an increased, but physiological, amount of progesterone (P(4)) supplied to the porcine corpus luteum (CL) affects luteal secretion of androgens and estrogens in freely moving gilts. On day 9 of the estrous cycle, the jugular veins as well as both ovarian arteries and both ovarian veins of gilts were cannulated. Progesterone was infused into the right ovarian arteries of experimental gilts (n=5) on days 10, 11 and 12 of the estrous cycle at a rate adequate to physiological retrograde transfer found during the middle luteal phase of the cycle. The left ovarian arteries of the experimental gilts were infused with saline. Both ovarian arteries of the control gilts (n=5) were infused with saline. The P(4) infusion rate was 0.62 microg/min (10 day), 2x0.62 microg/min (11 day) and 3x0.62 microg/min (12 day). Blood samples were collected from the jugular vein and both ovarian veins of the experimental and control gilts on days 10-12 of the estrous cycle before and after P(4) or saline infusion. The mean plasma androstenedione (A(4)) level in the ovarian vein ipsilateral to the P(4)-infused ovary was higher (p<0.01) on days 10-12 of the estrous cycle than those found in the contralateral ovarian vein of the experimental gilts as well as the control gilts. The ovarian venous level of testosterone (T) in the ovarian vein ipsilateral to the P(4)-infused ovary on days 10-12 of the estrous cycle was not significantly different (p>0.05) from those found in the contralateral ovarian vein of the experimental gilts and ovarian vein of the control gilts. However, on day 12, a decrease in T concentration was demonstrated in the ovarian vein ipsilateral to the P4-infused ovary in comparison to those of the contralateral and control ovarian veins. The mean plasma 17beta-estradiol (E(2)) level in the ovarian vein ipsilateral to the P(4)-infused ovary was lower on days 10-12 than those found in the contralateral ovarian vein of the experimental gilts and in the ovarian vein of the control gilts (p<0.001). The results of the present paper indicate that local elevation of P4 concentration in blood supplying the ovary during the middle luteal phase of the porcine estrous cycle affected local secretion of androgens and estrogens. The effect of P(4) on the secretion of androgens and estrogens suggested the existence of a short regulatory loop of a positive feedback for A(4) secretion and a negative feedback for E(2) secretion.

The aim of the study was to determine, in an experiment performed on conscious gilts, whether an increased amount of progesterone (P4) supplied to the porcine corpus luteum (CL), maintained within a physiological systemic concentration would influence its own secretion. On day 9 of the estrous cycle the jugular veins as well as both ovarian arteries and both ovarian veins were cannulated. In the experimental gilts (n=5), P4 was infused into the right ovarian arteries on days 10, 11 and 12 of the estrous cycle at a rate adequate for physiological retrograde transfer found during the middle luteal phase. The left ovarian arteries of these gilts were infused with saline. Both ovarian arteries of the control gilts (n=5) were infused with saline. The P4 infusion rate was 0.62 microg/min (10 day), 2 x 0.62 microg/min ( 11 day) and 3 x 0.62 microg/min (12 day) and physiological levels of the steroid were maintained. Blood samples were collected from the jugular vein and both ovarian veins in the experimental and control animals on days 10, 11 and 12 of the estrous cycle during two periods on each day: before and after P4 or saline infusion. The mean plasma P4 level in the ovarian vein ipsilateral to the P4-infused ovary was significantly (p<0.001) higher on days 10-12 of the estrous cycle than those found in contralateral ovarian vein of the experimental gilts and in the ovarian vein of the control gilts. This was also true for day 12 of the estrous cycle (p<0.001). However, on days 10 and 11 plasma P4 in the vein from the P4-infused ovary tended (p<0.061) to be higher than those in veins from the saline-treated ovaries. The mean P4 concentration in the ovarian vein ipsilateral to the P4-infused ovary did not vary significantly (p>0.05) among the particular days of the experiment. In contrast, mean P4 levels in the contralateral ovarian vein of the experimental gilts as well as in the ovarian vein of the control gilts tended to decrease (p<0.06) between day 10 and day 12. The results of the present paper indicate that during the middle luteal phase of the porcine estrous cycle (days 10-12), ovarian P4 secretion remained unaltered due to the elevation of P4 concentration in blood supplying the steroid-infused ovary, while a decrease in P4 concentration was observed in ovarian veins of the saline-infused ovaries. The influence of the progestagen on its own secretion suggests that on days 10-12 of the porcine estrous cycle there is a short regulatory loop of positive feedback between P4 being retrograde transferred into the ovary and P4 ovarian secretion.

This study investigated whether activin A and an inhibin-alpha subunit fragment (INHalpha) could permeate in a periovarian vascular complex from ovarian effluent into the ovarian artery and be retrograde transferred into the ovary. Radiolabelled activin A (125I-activin A) and INHalpha (125I-INHalpha) were injected (2.7 x 10(7) dpm) into follicles or corpora lutea (CL). It was demonstrated that 125I-activin A and 125I-INHalpha were released into the ovarian effluent and permeated into the arterial blood supplying the ovary in both phases of the cycle. The concentration of 125I-activin A in ovarian arterial blood was higher in the luteal phase (LP) than in the follicular phase (FP) (P<0.0001) in contrast to 125I-INHalpha which was higher in the FP (P<0.0001). The concentration of 125I-activin A in uterine tissues generally did not differ between the phases of the estrous cycle, but the concentration of 125I-INHalpha was higher (P<0.05) in the FP than in the LP. The concentration of 125I-activin A was higher in the LP in samples of endometrium and myometrium (P<0.05), as well as mesometrium (P<0.01), and higher in the FP in samples of mesometrium (P<0.05) close to the ovary than in the samples adjoining the uterine body. In the FP, the concentration of 125I-INHalpha was higher in endometrium and mesometrium close to the ovary than in samples adjoining the uterine body (P<0.05). In conclusion, the study demonstrated that it was possible for INHalpha and activin A to be retrograde transferred to the ovary. Thus this transfer could elevate their concentration in arterial blood supplied to the ovarian follicles or CL and may influence production of these peptides in the ovary, modulating ovarian function.

Platelets recruit leukocytes and mediate interactions between leukocytes and endothelial cells. Most studies examining this important platelet immune function have focused on the development of atherosclerosis, but similar mechanisms may contribute to acute and chronic vascular lesions in transplants. Platelets have been described as markers of transplant rejection, but little investigation has critically examined a role for platelets in transplant vasculopathy and, in particular, alloantibody-mediated transplant rejection. We now demonstrate using a skin transplant model that alloantibody indirectly induces platelet activation and rolling in vivo. Repeated IgG2a alloantibody injections result in sustained platelet-endothelial interactions and vascular pathology, including von Willebrand factor release, small platelet thrombi, and complement deposition. Maintenance of continued platelet-endothelial interactions are dependent on complement activation. Furthermore, we demonstrate that platelets recruit leukocytes to sites of alloantibody deposition and sustain leukocyte-endothelial cell interactions in vivo. Taken together, our model demonstrates an important role for platelets in alloantibody induced transplant rejection.

The local destination transfer of prostaglandin E2 (PGE2) from the uterine lymph to arterial blood supplying the ovary and its retrograde transfer to arterial blood supplying the uterine horn and the effect of additional delivery of PGE2 into the ovary on the secretion of steroid hormones was studied in early pregnant gilts. The injection of PGE2 under the perimetrium caused an increase (P<0.001) in PGE2 concentration in both uterine venous effluent and ovarian and uterine arterial blood. The infusion of PGE2 into the ovarian artery increased the concentration of progesterone in ovarian venous blood on day 13 of pregnancy during (P<0.05) and after (P<0.001) infusion, and on day 14 of pregnancy after infusion (P<0.01). In conclusion, local destination transfer of PGE2 from uterine lymph and venous blood to the ovary may affect luteal function, and retrograde transfer of PGE2 to the arterial blood supplying the uterus may contribute to the prevention of regressive changes of the endometrium in early pregnant gilts.

This study was designed to determine the efficiency and rate of testosterone (T) retrograde transfer during the follicular and luteal phase of the estrous cycle in gilts (n=27). The efficiency and the rate of the retrograde transfer of T from the ovarian effluent into blood supplying the ovary were determined for the first time under in vivo conditions. Ovarian arterial blood concentration of T was higher than that in systemic blood during both, the follicular phase (p<0.01) and luteal phase (p<0.0001). The efficiency of the retrograde transfer of T into ovarian arterial blood was not dependent on concentration of testosterone in the ovarian venous blood. However, the efficiency and the rate of the retrograde transfer of T differed between phases of the estrous cycle. The presented results suggest that local retrograde transfer enriched the porcine ovary with an additional amount of T which may affect the ovarian secretory function.

The paper summarizes results of a series of studies concerning luteolysis and early pregnancy in pigs. The involvement of the oxytocin (OT)/OT receptor system in the mechanism of corpus luteum (CL) protection during early pregnancy as well as the implication of luteinizing hormone (LH) in the endometrial prostaglandin (PG) release and synthesis are described. In addition, the role of leptin in the regulation of ovarian steroidogenesis and the expression of leptin and its receptor (OB-Rb) genes in hypothalamus, pituitary and reproductive tissues are reported. Moreover, a strong emphasis was placed on the mechanism of PGE2 participation in the local endocrine regulations of reproductive processes occurring in the utero-ovarian area as well as on the vascular endothelial growth factor (VEGF) ligand-receptor system in the ovary and uterus.