scholarly journals Plasma Luteinizing Hormone and Testosterone Concentrations in Different Breeds of Young Beef Bulls in the Tropics

1983 ◽  
Vol 36 (6) ◽  
pp. 545 ◽  
Author(s):  
TB Post ◽  
BM Bindon
Keyword(s):  
Luteinizing Hormone ◽  
Plasma Concentrations ◽  
Plasma Testosterone ◽  
Beef Bulls ◽  
The Tropics

Plasma concentrations of luteinizing hormone (LH) and testosterone were measured at 3, 8 and 11 months of age in 48 Africander cross (AX), 24 Brahman cross (BX), 21 Hereford-Shorthorn, selected (HSS) and 14 Hereford-Shorthorn, random-bred (HSR) bulls. In all breeds plasma LH was lower (P<O� 01) at 8 months (1�7 ng/ml) than at 3 months (2�6 ng/ml) or at 11 months (2�6 ng/ml). Over all ages there were no differences among breeds in mean plasma LH (AX 2�4, BX 2�4, HSS 1�8, HSR 2�2 ng/ml) and no breed X age interactions. In contrast, plasma testosterone increased significantly (P<O� 01) with age and at a faster rate in the AX breed, resulting in a significant (P<O� 05) breed X age interaction. Testosterone concentrations, though similar among breeds at 3 months of age (0�45 ng/ml), were much higher (P<O� 01) by 11 months in AX (2�56 ng/ml) than in BX (1�30 ng/ml), HSS (0�78 ng/ml) or HSR (0�66 ng/ml) bulls.

Endocrine correlates of territoriality, breeding stage, and body molt in free-living willow ptarmigan of both sexes

1990 ◽  
Vol 68 (10) ◽  
pp. 2130-2134 ◽  
Author(s):  
Susan J. Hannon ◽  
John C. Wingfield
Keyword(s):  
Luteinizing Hormone ◽  
Aggressive Behaviour ◽  
Follicle Stimulating Hormone ◽  
Plasma Concentrations ◽  
Egg Laying ◽  
Plasma Testosterone ◽  
Willow Ptarmigan ◽  
Free Living ◽  
Brood Rearing ◽  
Egg Formation

Concentrations of plasma testosterone, estradiol, corticosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were measured by radioimmunoassay in wild willow ptarmigan (Lagopus lagopus) of both sexes over the breeding season. In males, plasma concentrations of testosterone and LH increased once they became territorial, and this was paralleled by increases in comb size and initiation of molt into courtship plumage. A decline of testosterone and circulating LH levels during late territoriality and egg laying coincided with molt into summer plumage. FSH titers did not vary significantly through the season, but there was a trend for higher levels during the territorial period. Plasma concentrations of corticosterone were highest during pre- and late territoriality and brood rearing. In females, testosterone levels were about 13 times lower than in males and did not vary significantly, whereas LH was high from pre- to mid-territoriality and again in the brood season. Elevated LH levels may be correlated with aggressive behaviour in females. FSH and estradiol concentrations were highest during the period of egg formation. Corticosterone was correlated with chase time in both sexes.

Plasma concentrations of testosterone and luteinizing hormone in rutting reindeer bulls (Rangifer tarandrus)

1980 ◽  
Vol 58 (11) ◽  
pp. 2081-2083 ◽  
Author(s):  
K.-A. Stokkan ◽  
K. Hove ◽  
W. R. Carr
Keyword(s):  
Luteinizing Hormone ◽  
Testosterone Level ◽  
Plasma Concentrations ◽  
Plasma Testosterone ◽  
Plasma Samples ◽  
Diurnal Pattern ◽  
Testosterone Concentration ◽  
Peripheral Plasma ◽  
The Mean

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.

Variations in hypothalamic luteinizing hormone releasing hormone content and release in vitro and plasma concentrations of luteinizing hormone and testosterone in developing cockerels

1983 ◽  
Vol 99 (2) ◽  
pp. 311-319 ◽  
Author(s):  
P. G. Knight
Keyword(s):  
Luteinizing Hormone ◽  
Plasma Concentrations ◽  
Neural Mechanism ◽  
Plasma Testosterone ◽  
Release Process ◽  
Releasing Hormone ◽  
Residual Content ◽  
In Vitro Superfusion ◽  
Lh Releasing Hormone

An in-vitro superfusion system was used to study age-dependent changes in the functional activity of LH releasing hormone (LHRH) neurones terminating in the mediobasal hypothalamus (MBH) of the cockerel. Fragments of MBH tissue were obtained from cockerels killed at 8, 12, 16 and 20 weeks of age and both the rate of release of LHRH in vitro and the residual content of LHRH were determined by radioimmunoassay. Blood was collected from a similar group of cockerels of the same age for determination of plasma LH and testosterone concentrations. Superfused cockerel MBH showed both basal and depolarization-induced release of LHRH and the calcium-dependency of the release process was demonstrated. The viability of MBH in vitro was indicated by the observation that the rate of CO2 production by the tissue remained constant during a 3-h period of superfusion. Both the basal rate of release of LHRH (7·24 ±0·63 pg/2MBH per h; mean ± s.e.m., n = 4) and the residual content of LHRH (1·10 ± 0·24 ng/2MBH) were lowest in the 8-week-old cockerel and increased progressively to reach levels three (P<0·001) and 13 (P<0·001) times greater, respectively, by 20 weeks of age. Concentrations of LH and testosterone in plasma did not increase significantly until 16 weeks of age when the respective values were 5·86 ±0·37 μg/l and 1·88 ± 0·31 nmol/l (n = 11). Whereas plasma testosterone increased further to 5·76±0·42 nmol/l (n = 11) at 20 weeks of age, plasma LH fell significantly (P<0·02) to a concentration of 4·08 ± 0·41 μg/l (n = 11). These observations support the conclusion that the onset of sexual maturation in the cockerel is primarily determined by a central neural mechanism which results in an increased activity of LHRH neurones in the hypothalamus.

INFLUENCE OF METYRAPONE ON PLASMA CONCENTRATIONS OF TESTOSTERONE AND ANDROSTENEDIONE IN MAN

1971 ◽  
Vol 68 (3) ◽  
pp. 576-584 ◽  
Author(s):  
K. O. Nilsson ◽  
B. Hökfelt
Keyword(s):  
Body Weight ◽  
Male Patient ◽  
Gradual Increase ◽  
Plasma Concentrations ◽  
Plasma Testosterone ◽  
Testosterone Levels ◽  
Basal Plasma ◽  
Normal Males ◽  
A Minor ◽  
Secondary Hypogonadism

ABSTRACT Metyrapone was administered either orally, 750 mg every four h, in a total of six doses, or intravenously 30 mg per kg body weight as a four h infusion. In three males with normal endocrine functions, metyrapone given orally or intravenously induced a fall in plasma testosterone and an elevation of androstenedione within 2–8 h. When metyrapone was administered to a patient given dexamethasone to suppress endogenous ACTH production, the androstenedione levels did not alter whereas the testosterone levels showed a slight, transient decrease. In two normal females metyrapone administration was followed by a marked increase in plasma androstenedione whereas testosterone showed only a minor, gradual increase. In one male patient with Addison's disease the basal plasma testosterone was normal whereas the level of androstenedione was low. Following metyrapone intravenously, there was a slight suppression of plasma testosterone but no change in the androstenedione concentration. In one patient with primary hypogonadism, two with secondary hypogonadism and two with Klinefelter's syndrome the plasma testosterone was low under basal conditions and did not change following metyrapone. Basal plasma androstenedione was within the range for normal males and increased markedly following metyrapone in all the cases.

PLASMA CONCENTRATIONS OF LUTEINIZING HORMONE, TESTOSTERONE AND ANDROSTENEDIONE IN CASTRATED AND ADRENALECTOMIZED BULL CALVES

1978 ◽  
Vol 79 (1) ◽  
pp. 137-138 ◽  
Author(s):  
J. J. BASS ◽  
A. J. PETERSON ◽  
E. PAYNE
Keyword(s):  
New Zealand ◽  
Plasma Concentration ◽  
Luteinizing Hormone ◽  
Agricultural Research ◽  
Plasma Concentrations ◽  
Young Male ◽  
Research Centre ◽  
Similar Magnitude ◽  
Research Division ◽  
Bull Calves

Ministry of Agriculture and Fisheries, Research Division, Ruakura Agricultural Research Centre, Hamilton, New Zealand (Received 17 April 1978) An increase in the plasma concentration of luteinizing hormone (LH) occurs in response to castration in bull calves aged 1–4 months; this response is of similar magnitude to that seen in cattle castrated as adults (Odell, Hescox & Kiddy, 1970). In bull calves castrated at birth, however, there is no increase in the plasma concentration of LH until after 28 days of age (Bass, Peterson, Payne & Jarnet, 1977). In other species a range of responses to castration has been reported. Gonadectomy of male guinea-pigs 0–35 days after birth produces an increase in the plasma concentration of LH similar to that observed in guineapigs castrated as adults (Donovan, ter Haar, Lockhart, MacKinnon, Mattock & Peddie, 1975). In contrast, the castration of young male macaques does not cause an immediate increase in the

Plasma Testosterone, Luteinizing Hormone and Follicle-Stimulating Hormone one Day after Vasectomy

Andrologia ◽  
2009 ◽  
Vol 11 (4) ◽  
pp. 294-296 ◽  
Author(s):  
R.E. JOHNSONBAUGH ◽  
L.P. GEORGES ◽  
C.L. CZERWINSKI ◽  
M. EDSON
Keyword(s):  
Luteinizing Hormone ◽  
Follicle Stimulating Hormone ◽  
Plasma Testosterone ◽  
Stimulating Hormone

PROLONGED RELEASE BY DIOESTROUS RATS OF FOLLICLE-STIMULATING HORMONE DURING THE PERIOD OF OVULATION INDUCED BY LUTEINIZING HORMONE RELEASING HORMONE

1979 ◽  
Vol 81 (1) ◽  
pp. 109-118 ◽  
Author(s):  
SHUJI SASAMOTO ◽  
SHIGEO HARADA ◽  
KAZUYOSHI TAYA
Keyword(s):  
Luteinizing Hormone ◽  
Plasma Concentrations ◽  
High Plasma ◽  
Oestrous Cycle ◽  
Prolonged Release ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Follicular Maturation ◽  
Lh Rh ◽  
Premature Ovulation

When 1·0 μg luteinizing hormone releasing hormone (LH-RH) was given i.v. three times at 1 h intervals from 17.00 to 19.00 h on the day of dioestrus (day 0) to regular 4 day cyclic rats, premature ovulation was induced the next morning (day 1) with the number of ova present comparable to normal spontaneous ovulation. The next spontaneous ovulation occurred on the morning of day 5, 4 days after premature ovulation induced by LH-RH. Plasma concentrations of FSH and LH showed transient rises and falls within 1 h of administration of LH-RH; concentrations of FSH in the plasma decreased from 20.00 h on day 0 but markedly increased again from 23.00 h on day 0 to 02.00 h on day 1 and these high levels persisted until 14.00 h on day 1, with only a small increase of plasma LH during this period. The duration of increased FSH release during premature ovulation induced by LH-RH treatment was 6 h longer than the FSH surge occurring after administration of HCG on day 0. Surges of gonadotrophin were absent on the afternoon of day 1 (the expected day of pro-oestrus) and the surges characteristic of pro-oestrus occurred on the afternoon of day 4 and ovulation followed the next morning. The pituitary content of FSH did not decrease despite persisting high plasma levels of FSH during premature ovulation induced by either LH-RH or HCG on day 0. The changes in uterine weight indicated that the pattern of oestrogen secretion from the day of premature ovulation induced by LH-RH to the day of the next spontaneous ovulation was similar to that of the normal 4 day oestrous cycle. When 10 i.u. HCG were given on day 0, an increase in oestrogen secretion occurred on day 2, 1 day earlier than in the group given LH-RH on day 0. This advancement of oestrogen secretion was assumed to be responsible for the gonadotrophin surges on day 3. Similar numbers of fully developed follicles were found by 17.00 h on day 2 after premature ovulation induced by either LH-RH or HCG, suggesting that the shorter surge of FSH during premature ovulation induced by HCG had no serious consequences on the initiation of follicular maturation for the succeeding oestrous cycle in these rats. Administration of LH-RH on day 0 had no direct effect on the FSH surge during premature ovulation. Secretory changes in the ovary during ovulation may be responsible for this prolonged selective release of FSH.

Plasma testosterone surge and luteinizing hormone beta (LH-β) following parturition: lack of association in the male rat

1995 ◽  
Vol 133 (3) ◽  
pp. 366-374 ◽  
Author(s):  
Robert F McGivern ◽  
Ralph HM Hermans ◽  
Robert J Handa ◽  
Lawrence D Longo
Keyword(s):  
Luteinizing Hormone ◽  
Cesarean Section ◽  
Gnrh Antagonist ◽  
Male Rat ◽  
Plasma Testosterone ◽  
Treatment Groups ◽  
Natural Birth ◽  
Males And Females ◽  
Lh Secretion

McGivern RF, Hermans RHM, Handa RJ, Longo LD. Plasma testosterone surge and luteinizing hormone beta (LH-β) following parturition: lack of association in the male rat. Eur J Endocrinol 1995; 133:366–74. ISSN 0804–4643 Studies examining the role of luteinizing hormone (LH) in the initiation of the postnatal surge of testosterone in the male rat have produced ambiguous results. We examined the pattern of postnatal LH secretion in the newborn male rat, coincident with plasma testosterone levels, using a specific monoclonal antibody for LH-β. In some males, we attempted to block LH secretion and the postnatal testosterone surge by injecting males with a gonadotropin-releasing hormone (GnRH) antagonist, an LH antibody or progesterone immediately after delivery by cesarean section on day 22. Following injection, animals were immediately sacrificed (time 0) or housed in a humidified incubator maintained at 30°C until sacrifice at 60, 120, 240, 360 or 480 min after delivery. Plasma from individual animals was measured subsequently for LH-β and testosterone by radioimmunoassay. Results revealed a postnatal surge of testosterone which peaked at 2 h after delivery in males from all treatment groups. This testosterone surge was not accompanied by a postnatal rise in plasma LH-β in any group. Administration of the GnRH antagonist or the ethanol vehicle produced a transient drop of approximately 25% in LH-β levels at 60 min but did not decrease the postnatal testosterone surge in the same animals. Additional studies in untreated males and females born by cesarean section or natural birth also failed to reveal a postnatal rise in plasma LH-β during the first 3 h after birth. Plasma levels in both sexes were significantly lower in animals delivered by cesarean section compared to natural birth. Overall, these results indicate that the postnatal surge of testosterone occurs without a corresponding surge of detectable LH-β in the male rat. Robert F McGivern, 6363 Alvarado Ct, Suite 200H. San Diego, CA 92120, USA

Pituitary and gonadal responses to the long-term pulsatile administration of gonadotrophin-releasing hormone in fetal fetal sheep

1997 ◽  
Vol 153 (3) ◽  
pp. 385-391 ◽  
Author(s):  
G B Thomas ◽  
A N Brooks
Keyword(s):  
Plasma Concentrations ◽  
Reproductive Function ◽  
Inverse Correlation ◽  
Experimental Period ◽  
Immediate Release ◽  
Late Gestation ◽  
Plasma Testosterone ◽  
Fetal Sheep ◽  
Pulsatile Administration

Abstract The fetal hypothalamo–pituitary–gonadal axis reaches a peak in activity at mid-gestation and this is followed by a period of suppression which persists until the onset of puberty. The decline in gonadotrophic activity during late gestation is thought to reflect the maturation of central and peripheral feedback signals. In order to establish if sustained pituitary responsiveness is rate limiting to the reinstatement of reproductive function, we have examined the endocrine consequences of repeated pulsatile GnRH administration to male and fetal sheep during late gestation. Beginning on day 121 of gestation (term=145 days) chronically catheterized fetal sheep were given i.v. pulses of either 500 ng GnRH or saline every 2 h for 14 days. Pituitary and gonadal responses were assessed by measuring changes in plasma concentrations of LH, FSH, inhibin and testosterone (in male fetuses) in response to the first pulse of GnRH on day 1 and to the corresponding pulse on days 4, 7, 10 and 14. In response to the first pulse of GnRH there was an immediate release of LH, with the peak response being significantly (P<0·01) greater than on subsequent days. In male fetuses each pulse of LH was followed by a rise in plasma testosterone concentrations within 40–60 min. The amplitude of these testosterone responses increased significantly (P<0·01) after 9 days of treatment despite a decline in the plasma LH response. Basal FSH concentrations increased progressively (P<0·05) during pituitary stimulation with GnRH in both male and female fetuses. Immunoreactive inhibin concentrations were significantly (P<0·05) higher in males than in females, and there was a gradual increase throughout the experimental period irrespective of treatment. We observed no inverse correlation between inhibin and FSH concentrations. These data show that pulsatile administration of GnRH to fetal sheep during late gestation results in sustained re-activation of pituitary–gonadal function. The decline in fetal gonadotrophins, which is a characteristic feature of late gestation, is therefore likely to result from inadequate GnRH secretion from the fetal hypothalamus rather than an inhibition of pituitary function by peripheral feedback signals. Journal of Endocrinology (1997) 153, 385–391

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