Prolactin, progesterone and luteinizing hormone secretion after bromocriptine (CB-154) treatment in cyclic sows.

The effect of bromocriptine (CB-154) on prolactin, progesterone and luteinizing hormone (LH) secretion was studied in cyclic sows. Four sows were given subcutaneous injections of bromocriptine on Day 14 of the estrous cycle (70 mg CB-154) and again on Day 16 of the cycle (50 mg CB-154). Two control sows were injected with vehicle at similar time intervals. Blood samples were taken four times daily (0700, 1100, 1500 and 1900 h) from Day 11 of the estrous cycle to Day 2 of the following estrous cycle. Prolactin peaks during the estrous cycle were not observed after CB-154 treatment. CB-154 treatment had no effect on plasma LH concentration, but plasma progesterone concentrations appeared to fluctuate more and slowly decreased.

Porcine LH levels during the estrous cycle, gestation, parturition and early lactation.

Thirty-five sows were used in a study of plasma luteinizing hormone (LH) concentrations during the estrous cycle, including first and second estrus postweaning, during gestation, at parturition and during the first 5 d of lactation. After cannulation of the anterior vena cava via the cephalic vein, blood samples were collected four times daily for 2 d before estrus, during estrus and for 3 d after estrus and once daily at 1100 h throughout the rest of the estrous cycle. One sample was collected from each sow on alternate days (1100 h) during the gestation period. Four daily samples were obtained on d 60 through 68 of gestation and for 5 d after parturition. Preovulatory surges of LH occurred 8 to 32 h before standing estrus in four of seven sows during first estrus and in three of seven sows during second estrus. The mean preovulatory LH surge during the first estrus postweaning (3.00 +/- .46 ng/ml) was lower than that during second estrus (4.24 +/- .60 ng/ml). Throughout the first 12 d of gestation, LH concentrations were relatively high and variable, ranging from 1.2 to 2 ng/ml. They then decreased to a range of .42 to .62 ng/ml after d 24. Similar LH concentrations were noted throughout the remainder of gestation except for some slight fluctuations. Higher concentrations (P less than .05) were noted with evening collections (1900 h, 1:17 +/- .09 ng/ml) than in daytime collections (0700 h, .64 +/- .08: 1100 h, .61 +/- .06; 1500 h, .72 +/- .06 ng/ml) during d 60 to 68 of gestation. Low plasma concentrations of LH (.3 to .5 ng/ml) were observed for the 5 d before and during parturition. After parturition, considerable variation of LH occurred, with rising concentrations observed on d 5 postpartum. Results of this study illustrate the occurrence of LH surges before behavioral estrus with increased plasma LH during implantation.

Plasma prolactin levels in sows during pregnancy, parturition and early lactation.

Mean prolactin concentrations in the blood plasma ranged from 4.4 to 13.0 ng/ml during pregnancy up to the 2nd day pre partum. Concentrations increased to 20.3 ng/ml 2 days before and 103.4 ng/ml at 1 day before the start of farrowing. During farrowing values ranged from 124.2 to 147.3 ng/ml. On the 5th day of lactation the prolactin levels had fallen to 43.1 ng/ml.

Plasma prolactin concentrations during the oestrous cycle of sows.

Plasma prolactin levels were measured in 7 sows during the oestrous cycle after the 1st farrow. Blood samples were taken 4 times during the day (07:00, 11:00, 14:00 and 19:00 h). The prolactin concentration was determined by a double-antibody radioimmunoassay method. There was an increase in plasma prolactin at the second oestrus after weaning, with a peak of prolactin 4 days before oestrus, regardless of the length of the cycle.

Production of antibodies against the porcine luteinizing hormone by two immunization methods.

Two methods of rabbit immunization were applied: multisite intradermal injections of small doses and intramuscular injections of large hormone doses for obtaining antibodies against the porcine luteinizing hormone (LH). A high titre, specificity towards LH and affinity were obtained in rabbits immunized by both methods. In most animals the highest titre was noted 10 weeks after the first immunization.

Presence of erythropoiesis inhibitor in the urine of normal sheep and those with transfused polycythemia.

Presence of erythropoiesis inhibitor in the urine of normal sheep and those with transfused polycythaemia. Acta Physiol. Pol., 1978, 29 (1): 37-46. Urine from 18 ewes, normal and with transfused polycythemia, was analysed. The consequences of polycythemia were estimated in the period between 96 and 192h. The 24 h urine portions were separated on Sephadex G 100 columns, and after dialysis, tested biologically on normal mice of the BALB/c and Swiss strains. Changes of the erythropoietic activity in normal mice receiving the particular plasma fractions demonstrated that in the urine fraction IV, a factor with activity characteristic for the erythropoiesis inhibitor, is present in most normal sheep and in all those with moderate polycythemia.