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H D Hafs

Publications and source records attributed to H D Hafs.

At least 55 records · Page 3Linked to original sources
PubMed1975

Luteolysis, estrus and ovulation, and blood prostaglandin F after intramuscular administration of 15, 30 or 60 mg prostaglanding F2alpha.

During diestrus in three consecutive estrous cycles, each of six heifers was given (im) 30 mg, 15 mg (twice at 6-hr intervals) and 60 mg prostaglandin F2alpha (PGF2alpha) tham salt. Neither the decline in blood progesterone, the increase in blood estradiol, the duration or the peak of the LH surge, the interval to onset of estrus, nor the interval to ovulation was affected significantly by dose of PGF2alpha. Thus, relative to that after 30 mg PGF2alpha im, two injections of 15 mg at 6-hr intervals or 60 mg PGF2alpha did not hasten luteolysis. Thirty mg was an ample in dose of PGF2alpha to cause luteolysis. Regardless of im dose of PGF2alpha, blood PGF peaked at about 6.0 ng/ml within 10 minutes and returned to basal values (less than 1.0 ng/ml) within 90 minutes. In another trial, after a single iv injection of 5 mg PGF2alpha, blood PGF peaked (25 ng/ml) within 5 minutes and returned to basal values within 15 minutes. During a 30-minute infusion (0.5 mg/minute) of PGF2alpha, blood PGF plateaued at 29.5 ng/ml with a metabolic clearance rate of 17.0 liters per minute.

Animals↗
PubMed1975

Blood LH after PGF2alpha in diestrous and ovariectomized cattle.

Two experiments were conducted to determine whether the increased serum LH which occurs within 12 hr after a luteolytic dose of PGF2alpha is dependent upon changes in progesterone or estradiol secretion. In the first experiment, exogenous progesterone abolished the increase in serum LH caused by a subcutaneous injection of 25 mg PGF2alpha in diestrous heifers, but not in ovariectomized heifers. In the second experiment, progesterone pessaries were removed at 6 hr after a subcutaneous injection of 25 mg PGF2alpha. LH remained at pre-PGF2alpha values while the pessaries were in place, but began to increase within 1 hr after they were removed. Blood estradiol also remained at pre-PGF2alpha values until the pessaries were removed, and began to increase at 2 hr after pessary removal. We conclude that the increase in serum LH within 12 hr after PGF2alpha treatment in diestrous cattle is dependent upon withdrawal of progesterone; it is not due to increased serum estradiol.

Animals↗
PubMed1975

Stimulation effect of prostaglandin F2ALPHA on the plasma concentration of testosterone in bulls.

The concentrations of peripheral plasma testosterone were measured by radioimmunoassay in samples collected from five bulls, each given i.m. injections of 0, 5. 15, 30 and 60 mg prostaglandin F2alpha (PGF2alpha). Synchronized peaks in testosterone concentration occurred with maximum values 1.2h after treatment. These increases of testosterone persisted significantly longer than those observed to occur as natural episodic peaks during two 24 h periods in the same bulls. The mean peak testosterone concentration after PGF2alpha injection was related to the dose of PGF2alpha, values after 60 and 30 mg doses being significantly greater than after 15 mg. The response produced by a 5 mg dose was not significant. The results indicate that intramuscular injection of PGF2alpha, acutely stimulates synthesis and release of testosterone in fulls.

Animals↗
PubMed1975

Androgens in the bovine fetus and dam (38567).

Umbilical arterial and venous blood, and fetal testes were taken from 38 bovine fetuses at 90, 180 or 260 days of gestation. Concurrently blood also was taken from the jugular, and from the uterine artery and vein of the dams. Testosterone and androstenedione were determined by radioimmunoassays. Fetal testicular homogenates had 0.96 and 0.35 mug/g of testosterone and 0.39 and 0.50 mug/g of androstenedione at 180 and 260 days of gestation, respectively. Males had five to tenfold more serum testosterone and about twofold more androstenedione than female fetuses at each trimester of gestation. Male fetal blood testosterone decreased (P less than 0.01) from 2.7 to 0.3 ng/ml between 90 and 260 days of gestation. But, maternal testosterone and androstenedione increased (P less than 0.05) during gestation in cows with males, but not in cows with female fetuses. Testosterone was higher (P less 0.05) in cows carrying males than in cows with female fetuses. Androstenedione was higher in blood leaving the placenta on both the maternal and on the vetal sides suggesting placental synthesis of androstenedione.

Androstenedione↗
PubMed1975

The cycle of oestrus, ovulation and plasma levels of hormones in the mare.

The duration of the oestrous cycle and day of ovulation were recorded in six mares which were used for concurrent assay of plasma levels of sex steroids and pituitary LH concentration. Peak of progesterone were reached during dioestrus and those of oestradiol and androstenedione occurred 2 days before ovulation and were in decline on the day of ovulation. Plasma oestrone remained constant (between 9 and 12 pg/ml) throughout the cycle. Plasma LH rose to a maximum near to the time of ovulation, and thereafter decreased gradually until mid-dioestrus. The pattern of secretion is compared with that reported in other domesticated animals.

Androstenedione↗
PubMed1975

Oestrus, ovulation and plasma hormones after prostaglandin F2alpha in mares.

The luteolytic effect of PGF2alpha, administered by intrauterine infusion or subcutaneous injection during early dioestrus, was observed in mares of mixed breeds. An infusion of 10 mg on Days 7 to 9 after ovulation caused a sharp fall in plasma progesterone levels and induced oestrus and ovulation. Oestrus was significantly longer than in the natural cycle but the time of ovulation in relation to the end of oestrus was normal. The time of return to oestrus following luteolysis was not dependent on the amount of PGF2alpha within the range of doses given. Luteolysis could be induced as early as Day 5 following natural ovulation.

Androstenedione↗
PubMed1975

Control of estrus with prostaglandin F2alpha in mares: minimal effective dose and stage of estrous cycle.

To determine the minimal effective dose of prostagiandin (PGF2alpha; tromethamine salt) given subcutaneously (SC), mares of mixed breeding (400 kg av body weight) were given 2-, 3-, 5-, and 10-mg doses from 7 to 9 days after ovulation. In some but not all mares given doses of 2 and 3 mg of PGF2alpha, luteolysis occurred, but doses of 5 or 10 mg of PGF2alpha were luteolytic in all mares. The 10-mg dose of PGF2alpha did not cause luteolysis in mares 1 day after ovulation, and caused luteolysis in only 2 of 5 mares on day 3 after ovulation. The same dose of PGF2alpha, however, caused luteolysis in all mares on days 5 or 7 after ovulation. The results indicate that the minimal effective luteolytic dose of PGF2alpha (free-acid equivalent) is about 9 mug/kg, and that PGF2alpha is effective fromday 5 after ovulation.

Animals↗