scholarly journals The absence of corpus luteum formation alters the endocrine profile and affects follicular development during the first follicular wave in cattle

Reproduction ◽  
2008 ◽  
Vol 136 (6) ◽  
pp. 787-797 ◽  
Author(s):  
Ken-Go Hayashi ◽  
Motozumi Matsui ◽  
Takashi Shimizu ◽  
Natsuko Sudo ◽  
Ayako Sato ◽  
...  
Keyword(s):  
Corpus Luteum ◽  
Area Under The Curve ◽  
Follicular Development ◽  
Experimental Period ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Blood Collection ◽  
Gh Secretion ◽  
Endocrine Profile ◽  
Basal Concentration

We previously established a bovine experimental model showing that the corpus luteum (CL) does not appear following aspiration of the preovulatory follicle before the onset of LH surge. Using this model, the present study aimed to determine the profile of follicular development and the endocrinological environment in the absence of CL with variable nadir circulating progesterone (P4) concentrations during the oestrous cycle in cattle. Luteolysis was induced in heifers and cows and they were assigned either to have the dominant follicle aspirated (CL-absent) or ovulation induced (CL-present). Ultrasound scanning to observe the diameter of each follicle and blood collection was performed from the day of follicular aspiration or ovulation and continued for 6 days. The CL-absent cattle maintained nadir circulating P4throughout the experimental period and showed a similar diameter between the largest and second largest follicle, resulting in co-dominant follicles. Oestradiol (E2) concentrations were greater in the CL-absent cows than in the CL-present cows at day −1, day 1 and day 2 from follicular deviation. The CL-absent cows had a higher basal concentration, area under the curve (AUC), pulse amplitude and pulse frequency of LH than the CL-present cows. After follicular deviation, the CL-absent cows showed a greater basal concentration, AUC and pulse amplitude of growth hormone (GH) than the CL-present cows. These results suggest that the absence of CL accompanying nadir circulating P4induces an enhancement of LH pulses, which involves the growth of the co-dominant follicles. Our results also suggest that circulating levels of P4and E2affect pulsatile GH secretion in cattle.

Pulsatile secretion of progesterone from the human corpus luteum: poor correlation with bioactive LH pulses

1986 ◽  
Vol 111 (4) ◽  
pp. 553-557 ◽  
Author(s):  
Inese Z. Beitins ◽  
Maria L. Dufau
Keyword(s):  
Corpus Luteum ◽  
Temporal Relationship ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Biologically Active ◽  
Poor Correlation ◽  
Serum Progesterone ◽  
Progesterone Secretion ◽  
Wide Range ◽  
Human Corpus Luteum

Abstract. Having previously established that biologically active luteinizing hormone (LH) is secreted in episodic pulsations that vary in relation to the menstrual cycle, we investigated the possibility that a temporal relationship could exist between the bioactive LH pulses and progesterone secretion from the late corpus luteum. In 4 young women blood was withdrawn every 15 min for 8 h. Serum progesterone concentrations fluctuated at a mean frequency of 0.9 h with a wide range of amplitudes (13.8 to 1.7 ng/ml). Serum bioactive LH pulse frequency in contrast was 0.25 pulses/h in all subjects. The pulse amplitude was 18.2 to 12.4 mIU/ml (2nd IRP-hMG). These data reveal that within the 8 h-period studied, progesterone secretory pulses occurred four times more frequently as those for bioactive LH. Therefore it is unlikely that a temporal relationship exists between individual bioactive LH and pulses of progesterone secreted by the late corpus luteum.

scholarly journals INFLUENCE OF SEASON AND SOCIAL ENVIRONMENT ON THE REPRODUCTIVE-ENDOCRINE STATUS OF THE ADULT LANDRACE BOAR

1990 ◽  
Vol 70 (1) ◽  
pp. 121-128 ◽  
Author(s):  
V. L. TRUDEAU ◽  
L. M. SANFORD
Keyword(s):  
Social Environment ◽  
Late Summer ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Social Environments ◽  
Blood Samples ◽  
Testosterone Secretion ◽  
Endocrine Status ◽  
Reproductive Endocrine ◽  
Basal Concentration

Seasonal variations in LH, FSH, and testosterone secretion were investigated for adult Landrace boars housed in different social environments for 1 yr. Socially nonrestricted boars (n = 4) were penned adjacent to ovariectomized gilts that were hormonally brought into estrus every 2 wk, while socially restricted boars (n = 4) were kept in pens with solid walls. Mean hormone concentrations were determined from the assay of single AM and PM blood samples collected from the jugular vein by venipuncture once a month. In November, February, May and August, blood samples were collected serially over 12 h from jugular catheters for assessment of pulsatile LH and testosterone secretion, and the LH response to a GnRH injection (1 μg kg−1 body weight). Mean LH and testosterone concentrations were relatively high in all boars during the late summer and fall, and often were greater for the socially nonrestricted versus the restricted boars (group × month), P < 0.05) in the winter (December and January). Mean FSH concentration also varied with month (P < 0.05). Pulse analysis indicated that higher mean testosterone concentrations in November and August were the result of increases (month, P < 0.05) in testosterone-pulse frequency and basal concentration. Maximal mean LH concentration in August was associated with maximal (month, P < 0.05) LH-pulse amplitude and basal concentration. The amplitude of the LH peak following GnRH injection increased (P < 0.05) between November and May, and remained high in August. Key words: Gonadotropins, testosterone, blood, season, social environment, boar

scholarly journals Effect of calfhood nutrition on metabolic hormones, gonadotropins, and estradiol concentrations and on reproductive organ development in beef heifer calves

2020 ◽  
Vol 98 (10) ◽  
Author(s):  
Alan K Kelly ◽  
Colin Byrne ◽  
Mark McGee ◽  
George A Perry ◽  
Mark A Crowe ◽  
...  
Keyword(s):  
Anterior Pituitary ◽  
Reproductive Tract ◽  
Ovarian Tissue ◽  
Area Under The Curve ◽  
Dietary Treatment ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Ovarian Surface ◽  
Time Interaction ◽  
Beef Heifer

Abstract This study examined the effect of plane of nutrition on the endocrinological regulation of the hypothalamic–pituitary–ovarian (HPO) axis in beef heifer calves during a critical sexual developmental window early in calf hood. Forty Holstein-Friesian × Angus heifers (mean age 19 d, SEM = 0.63) were assigned to a high (HI; ADG 1.2 kg) or moderate (MOD; ADG 0.50 kg) nutritional level from 3 to 21 wk of life. Intake was recorded using an electronic calf feeding system, BW was recorded weekly, and blood samples were collected on the week of age 5, 10, 15, and 20 for metabolite, reproductive, and metabolic hormone determination. At 19 wk of age, on sequential days, an 8-h window bleed was carried out for luteinizing hormone (LH), follicle-stimulating hormone (FSH), and estradiol analysis. To characterize anterior pituitary gland function, an intravenous GnRH challenge was conducted (19 wk of age). Blood was collected via a jugular catheter every 15 min for 135 min for the analysis of LH, FSH, and estradiol. Calves were subsequently euthanized at 21 wk of age; the anterior pituitary, metabolic organs, and reproductive tract were weighed, and ovarian surface follicular numbers and oocytes recovered were recorded. Mean ADG was 1.18 and 0.50 kg for HI and MOD, respectively, resulting in a 76.6-kg difference in BW (P &lt; 0.001). Blood insulin, glucose, and IGF-1 concentrations were greater (P &lt; 0.001) for HI compared with MOD. There was a diet × time interaction for leptin (P &lt; 0.01); concentrations were greater in HI compared with MOD at 20 wk of age with no difference between treatments before this. Dietary treatment did not alter the concentrations of adiponectin or anti-mullerian hormone. There was a diet × time interaction for FSH, whereby MOD had greater concentrations than HI at 10, 15, and 20, but not at 5 wk of age. Over the duration of an 8-h window bleed (19 wk of age), serum concentrations of LH, LH pulse frequency, and LH pulse amplitude were unaffected by treatment, whereas FSH (0.23 vs. 0.43 ng/mL) and estradiol (0.53 vs. 0.38 ng/mL) concentrations were less than and greater, respectively, for HI than MOD (P &lt; 0.05). Likewise, following a GnRH challenge, the area under the curve analysis revealed greater (P &lt; 0.01) estradiol and lesser (P &lt; 0.01) FSH concentrations in calves on the HI relative to MOD diet, whereas concentrations of LH were unaffected (P = 0.26) between treatments. Ovarian surface follicle numbers were greater (P &lt; 0.05) in HI compared with MOD. Total reproductive tract, uterus, and ovarian tissue expressed relative to BW were greater (P &lt; 0.05) for HI compared with MOD. In conclusion, enhanced nutrition in early calfhood advances the ontogeny development of the HPO axis.

Pulsatile and nocturnal growth hormone secretions in men do not require periodic declines of somatostatin

2003 ◽  
Vol 285 (1) ◽  
pp. E163-E170 ◽  
Author(s):  
Eleni V. Dimaraki ◽  
Craig A. Jaffe ◽  
Cyril Y. Bowers ◽  
Peter Marbach ◽  
Ariel L. Barkan
Keyword(s):  
Growth Hormone ◽  
Diurnal Rhythm ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Pulse Generation ◽  
Sexually Dimorphic ◽  
Blood Samples ◽  
Gh Secretion ◽  
Stable Plasma ◽  
Hormone Secretions

Using a continuous subcutaneous octreotide infusion to create constant supraphysiological somatostatinergic tone, we have previously shown that growth hormone (GH) pulse generation in women is independent of endogenous somatostatin (SRIH) declines. Generalization of these results to men is problematic, because GH regulation is sexually dimorphic. We have therefore studied nine healthy young men (age 26 ± 6 yr, body mass index 23.3 ± 1.2 kg/m2) during normal saline and octreotide infusion (8.4 μg/h) that provided stable plasma octreotide levels (764.5 ± 11.6 pg/ml). GH was measured in blood samples obtained every 10 min for 24 h. Octreotide suppressed 24-h mean GH by 52 ± 13% ( P = 0.016), GH pulse amplitude by 47 ± 12% ( P = 0.012), and trough GH by 39 ± 12% ( P = 0.030), whereas GH pulse frequency and the diurnal rhythm of GH secretion remained essentially unchanged. The response of GH to GH-releasing hormone (GHRH) was suppressed by 38 ± 15% ( P = 0.012), but the GH response to GH-releasing peptide-2 was unaffected. We conclude that, in men as in women, declines in hypothalamic SRIH secretion are not required for pulse generation and are not the cause of the nocturnal augmentation of GH secretion. We propose that GH pulses are driven primarily by GHRH, whereas ghrelin might be responsible for the diurnal rhythm of GH.

scholarly journals A Reevaluation of the Question: Is the Pubertal Resurgence in Pulsatile GnRH Release in the Male Rhesus Monkey (Macaca mulatta) Associated With a Gonad-Independent Augmentation of GH Secretion?

Endocrinology ◽  
2015 ◽  
Vol 156 (10) ◽  
pp. 3717-3724
Author(s):  
M. Shahab ◽  
M. Vargas Trujillo ◽  
T. M. Plant
Keyword(s):  
Repeated Measures ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Detection Algorithm ◽  
Juvenile Male ◽  
Gh Secretion ◽  
Pulsatile Gnrh ◽  
Gnrh Release ◽  
Somatic Signal ◽  
Lh Secretion

A somatic signal has been posited to trigger the pubertal resurgence in pulsatile GnRH secretion that initiates puberty in highly evolved primates. That GH might provide such a signal emerged in 2000 as a result of a study reporting that circulating nocturnal GH concentrations in castrated juvenile male monkeys increased in a 3-week period immediately preceding the pubertal resurgence of LH secretion. The present study was conducted to reexamine this intriguing relationship, again in an agonadal model. Four castrated juvenile male monkeys were implanted with indwelling jugular catheters, housed in remote sampling cages, and subjected to 24 hours of sequential blood sampling (every 30 min) every 2 weeks from 19.5 to 22 months of age. Twenty-four-hour profiles of circulating GH concentrations were analyzed using the pulse detection algorithm, PULSAR, and developmental changes in pulsatile GH release with respect to the initiation of the pubertal rise of LH secretion (week 0; observed between 22.5 and 32 mo of age) were examined for significance by a repeated-measures ANOVA. Changes in the parameters of pulsatile GH secretion, including mean 24-hour GH concentration and GH pulse frequency and pulse amplitude for 3 (n = 4) and 6 (n = 3) months before week 0 were unremarkable and nonsignificant. These findings fail to confirm those of the earlier study and lead us to conclude that the timing of the pubertal resurgence of GnRH release in the male monkey is not dictated by GH. Reasons for the discrepancy between the two studies are unclear.

scholarly journals Inverse Relationship between Luteinizing Hormone and Body Mass Index in Polycystic Ovarian Syndrome: Investigation of Hypothalamic and Pituitary Contributions

2006 ◽  
Vol 91 (4) ◽  
pp. 1309-1316 ◽  
Author(s):  
Yanira L. Pagán ◽  
Serene S. Srouji ◽  
Yarisie Jimenez ◽  
Anne Emerson ◽  
Sabrina Gill ◽  
...  
Keyword(s):  
Body Mass Index ◽  
Body Mass ◽  
Polycystic Ovarian Syndrome ◽  
Area Under The Curve ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Hypothalamic Function ◽  
Normal Women ◽  
The Impact ◽  
Ovarian Syndrome

Context: Patients with polycystic ovarian syndrome (PCOS) have increased LH relative to FSH, but LH is modified by body mass index (BMI). Objective: The objective of the study was to determine whether the impact of BMI on neuroendocrine dysregulation in PCOS is mediated at the hypothalamic or pituitary level. Participants/Interventions/Setting: Twenty-four women with PCOS across a spectrum of BMIs underwent frequent blood sampling, iv administration of GnRH (75 ng/kg), and sc administration of the NAL-GLU GnRH antagonist (5 μg/kg) in the General Clinical Research Center at an academic hospital. Main Outcome Measures: LH pulse frequency and LH response to submaximal GnRH receptor blockade were used as measures of hypothalamic function; LH response to GnRH was used as a measure of pituitary responsiveness. Results: BMI was negatively correlated with mean LH, LH/FSH, and LH pulse amplitude. There was no effect of BMI on LH pulse frequency. Percent inhibition of LH was decreased in PCOS, compared with normal women (53.9 ± 1.5 vs. 63.1 ± 4.1, respectively; P &lt; 0.01), suggesting an increase in the amount of endogenous GnRH, but was not influenced by BMI. Pituitary responsiveness to GnRH was inversely correlated with BMI (peak LH, R = −0.475, P &lt; 0.02; and LH area under the curve R = −0.412, P &lt; 0.02). Conclusions: LH pulse frequency and quantity of GnRH are increased in PCOS, but there is no influence of BMI on either marker of hypothalamic function. The pituitary response to a weight-based dose of GnRH is inversely related to BMI in PCOS. These studies suggest that the effect of BMI on LH is mediated at a pituitary and not a hypothalamic level in PCOS.

Effects of hypothyroidism on the growth hormone axis in sheep

1994 ◽  
Vol 140 (3) ◽  
pp. 495-502 ◽  
Author(s):  
T P Fletcher ◽  
I J Clarke
Keyword(s):  
Growth Hormone ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Pulse Interval ◽  
Short Term ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Gh Secretion ◽  
Prolactin Response ◽  
Plasma Gh

Abstract This study examined the effect of thyroidectomy (TX) on the GH axis in sheep. The secretion of GH was monitored 10 and 77 days after TX or sham-TX when the effects on plasma GH and prolactin levels of the injection of 0·5 μg GH-releasing factor (GRF)/kg and 1 μg thyrotrophin-releasing hormone (TRH)/kg were also assessed. There were no significant differences in GH pulse amplitude, pulse frequency, inter-pulse interval and GH secreted/h between sham-TX and TX animals at 10 or 77 days after TX. There was no difference in the GH response to GRF injection in sham-TX sheep at any time but in TX sheep the GH response was significantly (P<0·05) attenuated 10 days after TX. After 77 days the GH response was similar to the response before TX. There was no measurable GH response to injection of TRH in sham-operated or TX sheep at any time. The prolactin response to TRH was not affected by TX or sham-TX. These results suggest that TX in sheep does not affect GH secretion but paradoxically the response to GRF is attenuated in hypothyroid sheep in the short term. TRH causes release of prolactin but not GH in sheep. Journal of Endocrinology (1994) 140, 495–502

Octreotide represses secretory-burst mass and nonpulsatile secretion but does not restore event frequency or orderly GH secretion in acromegaly

2004 ◽  
Vol 286 (1) ◽  
pp. E25-E30 ◽  
Author(s):  
Nienke R. Biermasz ◽  
Alberto M. Pereira ◽  
Marijke Frölich ◽  
Johannes A. Romijn ◽  
Johannes D. Veldhuis ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Cell Growth ◽  
Approximate Entropy ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Gh Secretion ◽  
Event Frequency ◽  
Basal Release ◽  
Long Acting ◽  
Secretion Rates

Octreotide is a potent somatostatin analog that inhibits growth hormone (GH) release and restricts somatotrope cell growth. The long-acting octreotide formulation Sandostatin LAR is effective clinically in ∼60% of patients with acromegaly. Tumoral GH secretion in this disorder is characterized by increases in pulse amplitude and frequency, nonpulsatile (basal) release, and irregularity. Whether sustained blockade by octreotide can restore physiological secretion patterns in this setting is unknown. To address this question, we studied seven patients with GH-secreting tumors during chronic receptor agonism. Responses were monitored by sampling blood at 10-min intervals for 24 h, followed by analyses of secretion and regularity by multiparameter deconvolution and approximate entropy (ApEn). The somatostatin agonist suppressed GH secretory-burst mass, nonpulsatile (basal) GH release, and pulsatile secretion, thereby decreasing total GH secretion by 86% (range 70-96%). ApEn decreased from 1.203 ± 0.129 to 0.804 ± 0.141 ( P = 0.032), denoting greater regularity. None of GH pulse frequency, basal GH secretion rates, or ApEn normalized. In summary, chronic somatostatin agonism is able to repress amplitude-dependent measures of excessive GH secretion in acromegaly. Presumptive tumoral autonomy is inferred by continued elevations of event frequency, overall pattern disruption (irregularity), and nonsuppressible basal GH secretion.

Growth hormone pulsatility in ram lambs of genotypes selected for fatness or leanness

1993 ◽  
Vol 57 (1) ◽  
pp. 119-125 ◽  
Author(s):  
J. M. Suttie ◽  
B. A. Veenvliet ◽  
R. P. Littlejohn ◽  
P. D. Gluckman ◽  
I. D. Corson ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Sampling Period ◽  
Pulse Amplitude ◽  
Basic Mechanism ◽  
Pulse Frequency ◽  
Carcass Weight ◽  
Pulse Detection ◽  
Gh Secretion ◽  
Positive Effects

AbstractAlthough it is known that growth hormone (GH) influences body composition in ruminants, the precise role of the pattern of GH secretion is not known. We have studied the pulsatile release of GH and insulin-like growth factor 1 (IGF 1) secretion in the male progeny of rams from lines selected either for {fat genotype) or against (lean genotype) fatness. Seventy-two lambs (36 each of the fat and lean genotype) were kept on high-quality pasture and randomly allocated within genotype to treatment at 2, 3, 3·5, 4,5 or 6 months of age. The procedure, which was identical for each sampling period, was to sample each lamb through a jugular cannula every 10 min for 6 h, and then, following an overnight fast, to slaughter and analyse the carcass for fat. All blood samples were analysed for GH and samples taken each hour for total plasma IGF 1. The GH data were further analysed with the pulse detection routine PULSAR. Carcass fatness, adjusted for cold carcass weight, was greater for fat genotype animals than for the lean genotype. GH was pulsatile in all profiles but the pattern differed with time and genotype. Mean GH and pulse amplitude decreased with time but did not differ between genotype, although the lean genotype had higher mean GH at five of the six sampling periods. In contrast, GH pulse frequency and IGF 1 were significantly higher for the fat compared with the lean genotype lambs. GH mean and amplitude correlated negatively with carcass fatness in both genotypes and GH pulse frequency and total IGF 1 correlated positively with fatness for the lean genotype only. When carcass weight and genotype were fitted to these relationships, GH mean and total IGF 1 were found to have independent negative and positive effects, respectively, on carcass fatness. Because GH mean had a separate effect on fatness independent of genotype or cold carcass weight, it is likely that GH secretion influences composition by the same basic mechanism in both genotypes. However, although the slopes of these relationships did not differ significantly between the genotypes, the intercepts were significantly different indicating that over and above the basic mechanism, at any level of GH, the lean genotype lambs were leaner than the fat genotype lambs. This may indicate a measure ofGH resistance in the fat genotype lambs.

Pulsatile and diurnal secretion of GH and IGF-I in the chronically catheterized pig fetus

1996 ◽  
Vol 149 (1) ◽  
pp. 125-133 ◽  
Author(s):  
M Bauer ◽  
N Parvizi
Keyword(s):  
Gestational Age ◽  
Diurnal Rhythm ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Diurnal Variations ◽  
Ontogenetic Changes ◽  
Blood Samples ◽  
Gh Secretion ◽  
Igf I ◽  
Fetal Pig

Abstract The ontogeny of GH and IGF-I secretion was investigated in the fetal pig. Pulse studies were performed to describe the pattern of GH release. Twenty-four-hour profiles were recorded to examine possible diurnal variations in these hormones. (I) Pulse studies. Blood samples were obtained at 15-min intervals for 2-h periods from 24 male and 20 female fetuses at various gestational ages (fetal day 89–113; term 113 ± 1 s.d.). Fetuses revealed a pulsatile GH release. The GH pulse frequency did not vary with gestational age in either sex (0·95 ± 0·19 pulses/h). In males the GH pulse amplitude decreased with increasing fetal age (r= −0·41; P<0·02). In female fetuses no significant correlation could be calculated. Mean GH concentrations fell significantly in male fetuses 3 to 4 days before delivery (P<0·05) and the same tendency was observed in females (P<0·06). Between fetal days 94 and 98 GH pulse amplitude and GH and IGF-I concentrations were higher in males than in females (P<0·01, P<0·001 and P<0·02 respectively). Fetal IGF-I secretion showed no ontogenetic changes in both sexes. However, maternal IGF-I concentrations increased with progressing gestation (r=0·46; P<0·001). (II) 24-h profiles. Eight male and four female late-gestational fetuses (fetal days 104–108) were studied. Blood samples were taken at 30-min intervals over 24 h. Dams and fetuses showed an episodic GH secretion over the 24-h period but no diurnal rhythm was observed. Whereas maternal IGF-I secretion was constant, fetal IGF-I release was characterized by marked fluctuations over the 24 h. In half of the fetuses (n=6) the fluctuations appeared at regular intervals. Again no diurnal rhythm existed. These data demonstrated that: (1) porcine fetal GH secretion is pulsatile and decreases shortly before birth; (2) a sex difference in GH and IGF-I concentrations exists between fetal days 94 and 98, suggesting that IGF-I is at least partially under the control of GH before birth; (3) fetal GH and IGF-I secretion is episodic over 24 h, but does not vary diurnally; and (4) fetal and maternal GH and IGF-I secretion are regulated independently. Journal of Endocrinology (1996) 149, 125–133

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