STIMULATORY EFFECT OF PROSTAGLANDIN F2α ON THE PLASMA CONCENTRATION OF TESTOSTERONE IN BULLS

1975 ◽  
Vol 66 (3) ◽  
pp. 329-338 ◽  
Author(s):  
N. B. HAYNES ◽  
H. D. HAFS ◽  
R. J. WATERS ◽  
J. G. MANNS ◽  
A. RILEY

SUMMARY 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 F2α (PGF2α). Synchronized peaks in testosterone concentration occurred with maximum values 1–2 h 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 PGF2α injection was related to the dose of PGF2α, 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 PGF2α acutely stimulates synthesis and release of testosterone in bulls.

1974 ◽  
Vol 77 (2) ◽  
pp. 408-416 ◽  
Author(s):  
F. Comhaire ◽  
D. Mattheeuws ◽  
A. Vermeulen

ABSTRACT The mean peripheral plasma concentration of oestradiol was found to be increased in 3 dogs with Sertoli cell tumours and in 3 dogs with seminomas, whereas the plasma testosterone showed no difference as compared to a group of dogs without testicular neoplasia. In two thirds of the cases the concentration of oestradiol in the spermatic venous blood draining the neoplastic testes was clearly higher than in the normal dogs. The testosterone concentration in the spermatic venous blood from the tumour bearing testes was lower than in the spermatic venous blood of the contralateral partner testes in the same dogs, though not different from the spermatic venous concentration in the control dogs. There was no correlation between the presence or absence of signs of feminization and the peripheral or spermatic venous concentration of sex steroids. It is concluded that not only Sertoli cell tumours, but also seminomas can secrete increased amounts of oestrogens. This is possibly due to the presence of a larger than normal mass of tissue capable of converting testosterone, or its precursors, to oestradiol.


1980 ◽  
Vol 58 (11) ◽  
pp. 2081-2083 ◽  
Author(s):  
K.-A. Stokkan ◽  
K. Hove ◽  
W. R. Carr

Concentrations of plasma testosterone and luteinizing hormone (LH) were measured in peripheral plasma from semidomestic, rutting reindeer bulls. Although the concentrations of plasma testosterone were high and showed large variations, those of LH were low and only a few episodic bursts could be detected in hourly samples taken throughout a 48-h period. The mean testosterone concentration in three bulls differed significantly and ranked the animals according to their position in a fighting hierarchy. The mean concentrations of LH did not differ significantly. Plasma samples from one reindeer bull sampled every 20 min for periods of 3 h indicated that an increment in LH concentration preceded a peak in testosterone. No diurnal pattern in testosterone concentrations could be detected, but testosterone peaks seemed to appear about every 3–4 h. The present study thus demonstrates that a series of plasma samples throughout the day is necessary to determine a true "testosterone level" in the reindeer bull.


1979 ◽  
Vol 12 (5) ◽  
pp. 289-305 ◽  
Author(s):  
H.G. Kattesh ◽  
E.T. Kornegay ◽  
F.C. Gwazdauskas ◽  
J.W. Knight ◽  
H.R. Thomas

1968 ◽  
Vol 42 (3) ◽  
pp. 477-481 ◽  
Author(s):  
K. DEMISCH ◽  
J. K. GRANT ◽  
W. BLACK

SUMMARY The concentration of testosterone was measured in the plasma of 16 healthy women in late pregnancy and in 14 of these after delivery. The mean testosterone concentration was found to be elevated in late pregnancy, although the range overlapped with the normal. There was a prompt return to normal concentrations after delivery. The significance of the results and of inactivation of testosterone by protein binding are discussed.


1975 ◽  
Vol 80 (4) ◽  
pp. 676-685 ◽  
Author(s):  
J. A. Elias ◽  
J. R. Newton ◽  
W. P. Collins

ABSTRACT The concentrations of prostaglandin F2α, progesterone, oestradiol, LH and cortisol have been determined in serial samples of peripheral venous plasma, before, during and after, the intravenous administration of prostaglandin F2α (50 μg/min, for 5 h) to 8 women in the luteal phase of the ovarian cycle. The results show that the mean concentrations of prostaglandin F2α and cortisol increased during the infusion by factors of 8.8 and 2.6 respectively. The highest levels of cortisol occurred after 3 h, and were significantly different (P < 0.0005, Student's t-test) from those obtained before the infusion. There were progressive decreases in the concentrations of LH and progesterone. After 3 h the values for LH were significantly lower (P < 0.0025) than those before the administration of prostaglandin F2α, and the lowest mean value was 26 % of the control. The values for progesterone were significantly lower (P < 0.025) after 5 h, and the mean value at this time was 38 % of the control. The pattern of the mean concentration for oestradiol was similar to that for progesterone. The levels of all 5 compounds had returned to normal within 1 h after completion of the infusion. The findings are discussed.


1976 ◽  
Vol 81 (2) ◽  
pp. 310-320 ◽  
Author(s):  
Teresa H. Cowley ◽  
B. G. Brownsey ◽  
M. E. Harper ◽  
W. B. Peeling ◽  
K. Griffiths

ABSTRACT The effect of Synacthen (β1–24-corticotrophin) on plasma testosterone and 4-androstene-3,17-dione concentrations in untreated patients with prostatic carcinoma, and in patients receiving endocrine therapy is described. An established specific radioimmunoassay was used for the measurement of testosterone, and a radioimmunoassay for 3-androstene-3,17-dione using thin layer chromatography has been developed. Administration of Synacthen resulted in a fall in testosterone in untreated patients, but a rise in 4-androstene-3,17-dione was observed. The plasma concentration of testosterone in all treated patients increased after administration of Synacthen. An increased concentration of plasma 4-androstene-3,17-dione was also observed in these treated patients after Synacthen, but the magnitude of the response was not significantly different from that of untreated patients. The work provides further evidence that in the patient being treated with oestrogen for carcinoma of the prostate a rise in plasma testosterone concentration will result from an increased secretion of ACTH.


1986 ◽  
Vol 108 (1) ◽  
pp. 75-80 ◽  
Author(s):  
V. Moutsatsou ◽  
R. E. Oakey

ABSTRACT The concentration of oestriol and the proportion of this hormone not bound to plasma protein were measured using radioimmunoassay and centrifugal ultrafiltration respectively, in 55 samples of plasma obtained from 12 women in the last 2 to 7 weeks of uncomplicated pregnancy. Among individuals, the mean plasma concentration of oestriol varied from 25·8 to 94·8 nmol/l; in nine subjects, there was a tendency for oestriol concentrations to increase as delivery approached. The mean proportion of oestriol not bound to plasma protein in the different subjects varied from 13·1 to 18·9%, but values from any individual subject remained essentially constant during the periods of study. These measured values were used to calculate, for each sample, the apparent concentration of oestriol not bound to plasma protein. The results were combined with analogous values for oestradiol and progesterone obtained from the same plasma samples and described in a previous study. It was found that (i) the mean ratio of the concentration of oestriol and oestradiol was 0·75, (ii) the mean concentration of non-protein-bound oestriol was 8·7 times that of non-protein-bound oestradiol, and (iii) in individual subjects, there was no consistent trend as delivery approached in the ratio of the concentration of progesterone to that of oestriol in either the total or non-protein-bound form. J. Endocr. (1986) 108, 75–80


1977 ◽  
Vol 86 (3) ◽  
pp. 634-640 ◽  
Author(s):  
Emma Florensa ◽  
Robert Harrison ◽  
Michael Johnson ◽  
Ezat Youssefnejadian

ABSTRACT The peripheral plasma levels of 20α-dihydroprogesterone (20α-DHP), progesterone (P) and 17-hydroxyprogesterone (17-OHP) were measured by radioimmuoassay techniques in 440 samples during normal human pregnancy between weeks 4 and 41. The levels of 20α-DHP in plasma from the 4th to the 6th week were between 6.0 and 6.6 ng/ml. From then until the 21st week the average plasma 20α-DHP concentrations remained at the same level between 4.0 and 6.3 ng/ml; they then rose significantly to and beyond term, levels reaching over 40 ng/ml. The range of mean plasma concentration of P during the first trimester of pregnancy fell to a nadir in the 9th week (170 ng/ml) then rose with increased gestation until the 39th week (190.4 ng/ml) followed by a slight and not significant drop. Single measurements of plasma 17-OHP from the 4th to the 6th week of pregnancy gave value between 2.8 and 3.6 ng/ml, but from the 7th week the mean plasma 17-OHP levels gradually declined, then from week 30 the 17-OHP concentration increased to reach a mean level of 7.63 ng/ml in the 41st week. The ratio P/20α-DHP increased from the 4th (3.5:1) to the 24th week (15.6:1) and then decreased from the 25th week (7.9:1) towards term (3.2:1).


1983 ◽  
Vol 97 (3) ◽  
pp. 369-377 ◽  
Author(s):  
M. T. Walker ◽  
R. T. Gemmell

The concentrations of progesterone and oestradiol-17β in the maternal plasma of Bennett's wallaby, Macropus rufogriseus rufogriseus, were measured daily throughout gestation after reactivation of the diapausing corpus luteum by removal of the suckling pouch young (RPY). Progesterone increased from mean concentrations of 382–424 pmol/l (120–133 pg/ml) during lactation to reach peak concentrations of 908 ± 172 (s.e.m.) pmol/l (285 ± 54 pg/ml) (n = 8) 4 days after RPY and 971 ± 220 and 971 ± 229 pmol/l (305 ± 69 and 305 ± 72 pg/ml) (n = 7) 24 and 25 days after RPY respectively. The mean gestation length (RPY to birth) was 26·8 ± 0·6 (s.d.) days (n = 6, range 25·75–27·50 days). Immediately after birth the plasma progesterone concentration declined to 299 ± 51 (s.e.m.) pmol/l (94 ± 16 pg/ml) (n=6). Oestradiol-17β increased from mean concentrations of 291–553 pmol/l (80–152 pg/ml) during lactation to reach a peak concentration of 967 ± 331 pmol/l (266 ± 91 pg/ml) (n = 9) 1 day after RPY. The concentration declined from 7 days after RPY and fluctuated between mean concentrations of 273 and 480 pmol/l before reaching a minimum of 207 ± 69 pmol/l (57 ± 19 pg/ml) (n = 6) 19 days after RPY. A transient increase to 542 ± 207 pmol/l (n = 7) occurred at 22 days after RPY. Plasma concentrations declined to a low of 156 ± 55 pmol/l (43 ± 15 pg/ml) (n = 6) 5 days after parturition. The mean concentration of plasma 13,14-dihydro-15-oxo-prostaglandin F2α was less than 2·8 nmol/l (1 ng/ml) for all samples from 13 days after RPY until 4 days after parturition. The results suggest that oestradiol-17β may be important in the early stages of blastocyst reactivation to synergize with progesterone in stimulating uterine secretions. 13,14-Dihydro-15-oxo-prostaglandin F2α is unlikely to be involved in the birth process and any luteolytic effect is likely to be from a local production of PGF2α.


1975 ◽  
Vol 66 (1) ◽  
pp. 21-29 ◽  
Author(s):  
NELIA T. VERMOUTH ◽  
R. P. DEIS

SUMMARY The effect of ovariectomy, progesterone and prolactin treatment on the action of prostaglandin F2α (PGF2α) was determined in pregnant rats. PGF2α (150 μg × 2) injected i.p. on day 19 or 18 of pregnancy induced lactogenesis about 25 h later and abortion on days 20 and 21 of pregnancy. Treatment with PGF2α (100 μg × 2 or 50 μg × 2) on day 19 induced lactogenesis around 22 or 38 h later, respectively, and abortion on day 21. PGF2α treatment on day 17 was less effective. Unilateral ovariectomy on day 17 of pregnancy induced lactogenesis 32 h later but not abortion. PGF2α (150 μg × 2) given on the day of surgery advanced lactogenesis 12 h and rats aborted on day 19. Bilateral ovariectomy on day 17 induced abortion between days 20 to 21, but if a single dose of PGF2α (300 μg) was injected on day 18, all the ovariectomized rats aborted on day 19. Progesterone (10 mg) injected into rats treated with PGF2α (150 μg × 2) on day 18, prevented abortion and delayed lactogenesis. Prolactin (1 mg × 4) treatment delayed only abortion. Serum prolactin levels were significantly higher 12 h after the last dose of PGF2α (150 μg × 2) in rats treated on days 17, 18 or 19 of pregnancy. Pretreatment with progesterone prevented the rise in prolactin concentration. These results suggest that the lactogenic and abortive action of PGF2α may be dependent on the uterine and plasma concentration of progesterone.


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