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

Gonadal steroids effect similar regulation of gonadotrophin subunit mRNA expression in both male and female rats

1992 ◽  
Vol 132 (1) ◽  
pp. 39-45 ◽  
Author(s):  
A. C. Dalkin ◽  
S. J. Paul ◽  
D. J. Haisenleder ◽  
G. A. Ortolano ◽  
M. Yasin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Steady State ◽  
Gnrh Antagonist ◽  
Gonadal Steroids ◽  
Female Rats ◽  
Plasma Testosterone ◽  
Subunit Gene ◽  
Gnrh Secretion ◽  
Male And Female Rats ◽  
Males And Females

ABSTRACT Gonadal steroids can act both indirectly via gonadotrophin-releasing hormone (GnRH) and directly on the pituitary to regulate gonadotrophin subunit gene expression. Recent studies to assess a possible direct action at the pituitary have shown that testosterone, when given to males in the absence of endogenous GnRH action, selectively increases FSH-β mRNA concentrations. Conversely, in females, oestradiol appears to regulate gonadotrophin subunit mRNAs primarily via GnRH. The present study was designed to determine whether these differing results reflect specific actions of the gonadal steroids themselves or different responses of the pituitary gonadotroph cells in males and females. Rats which had been castrated 7 days earlier were given silicone elastomer implants (s.c.) containing oestradiol (plasma oestradiol 68 ± 4 ng/l) in males or testosterone (plasma testosterone 3·5 ± 0·3 μg/l) in females in the absence or presence of a GnRH antagonist. Seven days later pituitaries were removed and steady-state mRNA concentrations measured by dotblot hybridization. In males, oestradiol reduced LH-β and FSH-β but not α mRNA. The antagonist reduced levels of all three subunit mRNAs in males and the addition of oestradiol had no further effect, suggesting that oestradiol regulates gonadotrophin subunit gene expression in males by suppressing GnRH secretion. In females, testosterone reduced all three subunit mRNAs though FSH-β remained threefold higher than in intact animals. The GnRH antagonist was as effective as testosterone alone and reduced α and LH-β to levels found in intact animals. FSH-β mRNA was partially reduced by antagonist alone in ovariectomized females but the addition of testosterone increased FSH-β twofold versus antagonist alone (as has been observed in males). These findings, together with earlier data, suggest that testosterone increased FSH-β twofold versus antagonist alone (as has been observed in males). These findings, together with earlier data, suggest that testosterone reduces gonadotrophin subunit mRNAs by inhibiting GnRH secretion and also acts directly on the gonadotroph to increase steady-state FSH-β mRNA concentrations in both males and females. Journal of Endocrinology (1992) 132, 39–45

Selection of fewer dominant follicles in Trio carriers given GnRH antagonist and luteinizing hormone action replaced by nonpulsatile human chorionic gonadotropin†

2020 ◽  
Vol 103 (6) ◽  
pp. 1217-1228
Author(s):  
Victor E Gomez-León ◽  
João Paulo Andrade ◽  
Brian W Kirkpatrick ◽  
Sadrollah Molaei Moghbeli ◽  
Alvaro García-Guerra ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Chorionic Gonadotropin ◽  
Human Chorionic Gonadotropin ◽  
Gnrh Antagonist ◽  
Maximum Diameter ◽  
High Fecundity ◽  
Follicle Diameter ◽  
Follicle Selection ◽  
Selection Of

Abstract Studying selection of multiple dominant follicles (DFs) in monovulatory species can advance our understanding of mechanisms regulating selection of single or multiple DFs. Carriers of the bovine high fecundity Trio allele select multiple DFs, whereas half-sib noncarriers select a single DF. This study compared follicle selection during endogenous gonadotropin pulses versus during ablation of pulses with Acyline (GnRH antagonist) and luteinizing hormone (LH) action replaced with nonpulsatile human chorionic gonadotropin (hCG) treatment in Trio carriers (n = 28) versus noncarriers (n = 32). On Day 1.5 (Day 0 = ovulation), heifers were randomized: (1) Control, untreated; (2) Acyline, two i.m. doses (Days 1.5 and D3) of 3 μg/kg; (3) hCG, single i.m. dose of 50 IU hCG on Day 1.5 followed by daily doses of 100 IU; and (4) Acyline + hCG. Treatments with nonpulsatile hCG were designed to replace LH action in heifers treated with Acyline. Acyline treatment resulted in cessation of follicle growth on Day 3 with smaller (P < 0.0001) maximum follicle diameter in Trio carriers (6.6 ± 0.2 mm) than noncarriers (8.7 ± 0.4 mm). Replacement of LH action (hCG) reestablished follicle diameter deviation and maximum diameter of DFs in both genotypes (8.9 ± 0.3 mm and 13.1 ± 0.5 mm; P < 0.0001). Circulating follicle stimulating hormone (FSH) was greater in Acyline-treated than in controls. Finally, Acyline + hCG decreased (P < 0.0001) the number of DFs from 2.7 ± 0.2 to 1.3 ± 0.2 in Trio carriers, with most heifers having only one DF. This demonstrates the necessity for LH in acquisition of dominance in Trio carriers (~6.5 mm) and noncarriers (~8.5 mm) and provides evidence for a role of GnRH-induced FSH/LH pulses in selection of multiple DFs in Trio carriers and possibly other physiologic situations with increased ovulation rate.

EFFECT OF AN ANABOLIC STEROID (METANDIENON) ON PLASMA LH, FSH, AND TESTOSTERONE AND ON THE RESPONSE TO INTRAVENOUS ADMINISTRATION OF LRH

1976 ◽  
Vol 83 (4) ◽  
pp. 856-864 ◽  
Author(s):  
Pentti Holma ◽  
Herman Adlercreutz
Keyword(s):  
Luteinizing Hormone ◽  
Intravenous Administration ◽  
Anabolic Steroid ◽  
Plasma Levels ◽  
Oral Intake ◽  
Plasma Testosterone ◽  
Before And After ◽  
The Mean ◽  
Pre Treatment ◽  
Lh Secretion

ABSTRACT Plasma levels of testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) as well as the response of LH and FSH to the intravenous administration of 100 μg of luteinizing hormone releasing hormone (LRH) were measured in 16 well-trained athletes (mean age 30 years) before and after 2 months of daily oral intake of 15 mg of metandienon, an anabolic steroid (Anabolin®, 17α-methyl-17β-hydroxy-1,4-androstadien-3-one, Medica, Finland). All athletes continued to train regularly, just as they had done for several years. During administration of metandienon the mean plasma testosterone level fell 69%, from 29.4 ± 11.6 nmol/l to 9.1 ± 7.5 nmol/l. The mean plasma levels of LH and FSH also fell significantly (P < 0.001 and P < 0.01, respectively), both about 50%. Because LH and FSH levels were low after administration of the steroid the maximum stimulation values after LRH administration were also lower than pre-treatment values although the mean increments did not differ significantly before and after administration of the anabolic steroid. However, after treatment, the FSH response curve had a biphasic pattern in most subjects, with peaks at 10 to 20 and 50 to 60 min after the iv injection of LRH. Administration of LRH after the treatment period had no effect on FSH secretion in two subjects and no effect on LH secretion in one. Our results show that administration of an anabolic steroid causes a pronounced lowering of plasma levels of testosterone, LH and FSH but causes no gross alteration in the response of LH secretion to stimulation by LRH. The reason for the biphasic response pattern of FSH to LRH administration in most subjects is not known.

Effects of oestradiol, progesterone and androstenedione on the pulsatile secretion of luteinizing hormone in ovariectomized ewes during spring and autumn

1983 ◽  
Vol 96 (2) ◽  
pp. 181-193 ◽  
Author(s):  
G. B. Martin ◽  
R. J. Scaramuzzi ◽  
J. D. Henstridge
Keyword(s):  
Luteinizing Hormone ◽  
Breeding Season ◽  
Negative Feedback ◽  
Combined Treatment ◽  
Pulse Frequency ◽  
The Other ◽  
Ovarian Steroids ◽  
Pulsatile Secretion ◽  
Lh Secretion

The effects of oestradiol-17β, androstenedione, progesterone and time of the year on the pulsatile secretion of LH were tested in ovariectomized Merino ewes (n = 32). The steroids were administered by small subcutaneous implants, and the LH pulses were observed in samples taken at intervals of 15 min for 12 h in spring 1979, autumn 1980 and spring 1980, seasons corresponding to successive periods of anoestrus, breeding season and anoestrus. During spring, oestradiol alone was able to reduce the frequency of the LH pulses, while progesterone, either alone or in combination with oestradiol, had little effect. During autumn, on the other hand, neither oestradiol nor progesterone could significantly reduce the frequency of the pulses when administered independently, whereas the combined treatment was very effective. Androstenedione had no significant effect on pulse frequency at either time of the year, either alone or in any combination with oestradiol and progesterone. The basal levels of LH, over which the pulses are superimposed, were reduced by oestradiol alone in both seasons. Progesterone alone had no consistent effects, but interacted significantly with oestradiol and this combined treatment maintained low basal levels most effectively at all times. Androstenedione had no significant effect. The amplitude of the pulses increased throughout the course of the experiment. Within seasons, the amplitudes were significantly higher in the presence of oestradiol and progesterone, but were not significantly affected by androstenedione. It was concluded that certain of the ovarian steroids exert negative feedback on the tonic secretion of LH primarily by reducing the frequency of the pulses, and that the changes in LH secretion attributable to season and phases of the oestrous cycle can be accounted for entirely by the responses of the hypothalamus to oestradiol and progesterone. The role of the androstenedione secreted by the ovary in the ewe remains obscure.

scholarly journals Inhibition of Gonadotropin-Induced Testosterone Secretion by the Intracerebroventricular Injection of Interleukin-1β in the Male Rat*

Endocrinology ◽  
1997 ◽  
Vol 138 (3) ◽  
pp. 1008-1013 ◽  
Author(s):  
Andrew V. Turnbull ◽  
Catherine Rivier
Keyword(s):  
Gnrh Antagonist ◽  
Plasma Corticosterone ◽  
Male Rat ◽  
Neural Pathways ◽  
Central Administration ◽  
Testosterone Secretion ◽  
Central Origin ◽  
Lh Secretion ◽  
The Brain ◽  
Circulating Levels

Abstract The intracerebroventricular (icv) injection of the proinflammatory cytokine interleukin (IL)-1β is known to significantly decrease plasma LH levels in the male rat, thereby lowering testosterone (T) secretion. We show here that central administration of this cytokine (20–80 ng) also inhibits T secretion in response to human CG (hCG), an effect that is apparent already when IL-1β is injected 15 min before hCG. This phenomenon is independent of LH secretion because lowering LH levels with the potent GnRH antagonist Azaline B neither mimics nor affects the suppressive influence of icv IL-1β on the hCG-induced T secretory response. Elevations in plasma corticosterone levels do not seem to play a role either, because icv IL-1β is able to blunt hCG-induced T secretion in animals whose corticosterone has been removed by adrenalectomy or reduced by the administration of antibodies to CRF. Furthermore, the observation that icv IL-1β inhibits the T response to hCG before elevations in plasma IL-6 concentrations are detectable, and that central treatment with the cytokine is more effective than iv treatment, indicates that circulating levels of neither IL-1β nor IL-6 are important mediators of this effect. Collectively, these results lead us to propose that IL-1β of central origin influences neural pathways linking the brain and the testes, resulting in decreased testicular responses to hCG.

Dynamic changes in plasma luteinizing hormone and testosterone after stress in the male rat. Influence of adrenalectomy

1984 ◽  
Vol 62 (9) ◽  
pp. 1231-1233 ◽  
Author(s):  
Gérard Lescoat ◽  
Denise Lescoat ◽  
Danièle Garnier
Keyword(s):  
Luteinizing Hormone ◽  
Plasma Level ◽  
Male Rats ◽  
Male Rat ◽  
Plasma Testosterone ◽  
Intact Male ◽  
Dynamic Changes ◽  
High Level ◽  
Adrenalectomized Rats ◽  
Stimulation Of

In 60-day old intact male rats, stress imposed by a strange environment increased the levels of plasma LH and testosterone. Adrenalectomy, performed at 50 days of age, decreased plasma level of testosterone in basal conditions. However, without affecting the plasma level of LH significantly, stress increased plasma testosterone, albeit to a lesser extent, in the adrenalectomized rats. Stimulation of the testicular secretion by the high level of ACTH seems to be the most likely explanation for the observed testosterone peak in the adrenalectomized rat.

Hypoglycemia-induced Suppression of Luteinizing Hormone (LH) Secretion in Intact Female Rhesus Macaques: Role of Vasopressin and Endogenous Opioids

Stress ◽  
2002 ◽  
Vol 5 (2) ◽  
pp. 113-119 ◽  
Author(s):  
Joaquin Lado-Abeal ◽  
Jeffrey A. Clapper ◽  
B. Chen Zhu ◽  
Corey M. Hough ◽  
Peter J. Syapin ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Rhesus Macaques ◽  
Endogenous Opioids ◽  
Intact Female ◽  
Female Rhesus ◽  
Lh Secretion ◽  
Female Rhesus Macaques
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