Steroid hormone and luteinizing hormone concentrations in the anestrous sow.
This investigation characterized serum concentrations of luteinizing hormone (LH), estradiol-17 beta (E2), progesterone (P4) and cortisol (C) in anestrous sows. Twenty-two sows that had not returned to estrus within 45 days after weaning (anestrous sows), and ten sows that had returned to estrus within seven days following weaning (cyclic sows) were nonsurgically fitted with indwelling jugular vein cannulae. Blood samples were collected at 6 h intervals for seven days and at 15 min intervals for 8 h on the fifth day after cannulation. Serum LH concentrations were determined in all samples, while C, E2 and P4 levels were quantitated in serum collected at 6 h intervals. Serum P4 concentrations in anestrous sows were consistently less than 0.5 ng/mL, and E2 levels ranged from 10 to 19 pg/mL. Concentrations of LH remained less than 1.0 ng/mL in anestrous sows, whereas a preovulatory LH surge was observed in five of ten cyclic sows. There was a circadian rhythm in mean C levels with C peaks occurring at 0600 or 2400 h and nadir levels observed at 1200 and 1800 h. Few differences in C levels were detected between anestrous and cyclic sows. It was evident that anestrous sows did not exhibit cyclic or predictable variations in steroid hormone concentrations. Unfortunately, the results of this study failed to elucidate the endocrine pathogenesis of the anestrous sow.
Identification and distribution of prostaglandin E receptors on porcine luteal cells.
This study examined whether pig luteal cells contain specific prostaglandin (PG) E receptors. Corpora lutea, from PG 600R -induced cycling prepubertal gilts or naturally cycling gilts, were dissociated enzymatically, and large, small, and mixed cells were obtained by elutriation. Preliminary experiments demonstrated that optimal [3H]PGE2 binding to mixed cells was obtained after incubation at 22 degrees C for 2 h in binding buffer containing 1% BSA at pH 7.38. In addition, [3H]PGE2 binding was displaced by prostaglandins in the order of PGE2 approximately or = to PGE1 > PGF2a > > PGI2. The mixed, large, and small cells were assayed for specific PGE2 binding by displacement analysis with [3H]PGE2 and varying concentrations of unlabeled PGE2. Each gilt was assigned to group A (n = 6) or group B (n = 3) on the basis of whether the serum progesterone concentrations in that pig had increased or decreased, respectively, from 2 days before ovary collection to the time of ovary collection. Luteal cells from PG 600R -induced cycling prepubertal gilts had similar (p > 0.1) affinities and numbers of PGE receptors. In group A, the mixed cells contained a PGE binding site with a Kd of 21.1 +/- 1.1 nM and a concentration of 5.0 x 10(5) sites per large cell. Affinities of PGE receptors were similar (p > 0.1) regardless of cell types and functional status. PGE receptor concentrations were higher on large cells than on small cells (p > 0.05) and in group A than in group B (p = 0.006). These data demonstrated that PGE receptors primarily exist on porcine large luteal cells and that the concentration of PGE receptors appeared to be related to corpus luteum functional status.
Comparison between Two Chemicals for Reducing Scale Formation in Reverse Osmosis Systems
In this present research was transacted with the calcium carbonate scale inhibition on the membrane surface of the reverse osmosis desalination system. Influence of changing feed solution flow rate (10-25)l/h, pH of the feed solution (6-10) on the recovery ,penetrate flow rate and total dissolved solid in (RO) system by using solution of calcium carbonate as feed solution was investigated, furthermore the effect of adding two types of scale inhibitor ,zinc chloride and polyamino polyether methylene phosphonate with difference concentration (2-8)mg/l for zinc chloride and (8-15) mg/l for polyamino polyether methylene phosphonate was calculated. The results showed that the permeate rate increases as the feed flow rate augmentation ,while it reducing with time, the total dissolved solids decreases as the feed flow rate increases while it increases with time and recovery rate decreases as the feed flow rate increases and it also decreases with time. It was concluded that the permeate rate decreases as the feed solution pH value increases and it cause high scale forming thus decrease the permeate TDS.By adding the scale inhibitor, it was found that the permeate rate and recovery rates increases as the concentration of inhibitor increases while the total dissolved solids decreases in the permeate with increasing the concentration of both inhibitors .It was discovered that Polyamino polyether methylene phosphonate more sturdy than zinc chloride as scale inhibitor for reverse osmosis desalination system in all concentrations was studied in this article.