PITUITARY GONADOTROPHIN SECRETION DURING THE FIRST WEEKS OF PREGNANCY

1977 ◽  
Vol 85 (1) ◽  
pp. 177-188 ◽  
Author(s):  
Sten Jeppsson ◽  
Gunnar Rannevik ◽  
Jan I. Thorell
Keyword(s):  
Longitudinal Study ◽  
Pregnant Women ◽  
Luteal Phase ◽  
Elevated Level ◽  
Normal Limit ◽  
Follicular Phase ◽  
Gonadotrophin Secretion ◽  
Early Follicular Phase ◽  
Basal Plasma ◽  
Pituitary Secretion

ABSTRACT A longitudinal study of basal plasma LH and FSH and their responses to 25 μg LRH iv as well as basal levels of oestradiol, progesterone, prolactin and HCG was performed every week in 3 women, pregnant after heterologous insemination, from conception until the 6th week of gestation. A comparative study was carried out in 7 women in cycles in which no conception occurred after insemination. All hormones were assayed with radioimmunoassay. LH was measured with a specific assay for native LH, which did not cross-react with HCG. A decrease in basal levels of LH and FSH as well as decreasing responses to LRH was found during the first 2 weeks of gestation. These changes did not differ from what was observed during the luteal phase in the non-conception cycles. One week later the basal FSH levels and the FSH response in the pregnant women showed a further decrease, while in the non-pregnant women, now reaching the early follicular phase, a rise in FSH basal levels occurred. The basal levels of LH and the LH response, however, did not differ from that found in the nonpregnant women at this time. FSH basal levels remained below the lower normal limit in eumenorrhoic women from the 3rd week of gestation. By this time the FSH response was almost completely inhibited. The LH basal levels, however, remained above the lower normal limit in eumenorrhoic women, but the LH response to LRH progressively decreased and was completely inhibited by the 5th week of gestation. In the non-conception cycles the LH response varied with the levels of oestradiol in plasma. This was not found in the pregnant women as the decrease in gonadotrophin response occurred while oestradiol remained at mid-cycle levels during the first 4 weeks of gestation. Rather it seems that the increasing and continuously elevated level of progesterone, in the presence of appropriate levels of oestradiol, might be the main go nadal steroid responsible for the diminishing pituitary secretion. The contribution of HCG to the further decrease in gonadotrophin secretion after the 2nd week of pregnancy cannot be answered by the present studies. Prolactin remained at non-pregnant levels until the 6th week of gestation, and appeared to have no influence on the secretion of gonadotrophins during early pregnancy.

THE SEQUENCE OF PITUITARY RESPONSES TO SYNTHETIC LUTEINIZING HORMONE RELEASING HORMONE (LH-RH) THROUGHOUT THE NORMAL MENSTRUAL CYCLE

1975 ◽  
Vol 79 (4) ◽  
pp. 625-634 ◽  
Author(s):  
Elwyn M. Grimes ◽  
Irwin E. Thompson ◽  
Melvin L. Taymor
Keyword(s):  
Menstrual Cycle ◽  
Luteal Phase ◽  
Follicular Phase ◽  
Lh Surge ◽  
Luteinizing Hormone Releasing Hormone ◽  
Late Luteal Phase ◽  
Normal Menstrual Cycle ◽  
Early Follicular Phase ◽  
Lh Rh ◽  
Late Follicular Phase

ABSTRACT Thirty-one ovulatory women between 20 and 33 years of age were given 150 μg of synthetic LH-RH during different phases of the menstrual cycle. Five patients were studied during the early follicular phase (days 4–7); 10 patients during the late follicular phase (days 9–12); 6 patients during the "LH Surge"; 5 patients during the early luteal phase (days 14–16); 3 patients during mid-luteal phase (days 17–21); and 2 patients during late luteal phase (days 22–27). Oestrogen, progesterone, FSH and LH levels were determined from 30 min prior to LH-RH administration to 90 min thereafter in all cases. LH response to LH-RH increased progressively during the follicular phase. Enhanced pituitary responsiveness to LH-RH occurred at mid-cycle for both LH and FSH and maximum LH responses occurred during the "LH Surge" and early luteal phase. LH responses during the mid and late luteal phases were similar to late follicular phase responses. There were no significant differences between FSH responses during the early follicular, late follicular, mid-luteal and late luteal phases. Maximum pituitary responsiveness appears to occur in a gonadal steroid milieu of high oestrogen levels in association with rising but low progesterone levels. Progesterone or a crucial oestrogen: progesterone ratio may in fact potentiate pituitary release of LH during the early stages of corpus luteum formation. Pituitary responsiveness to LH-RH correlates positively with basal LH and oestrogen levels during the menstrual cycle and with the oestrogen:progesterone ratio during the luteal phase.

THE FLUORIMETRIC DETERMINATION OF PROGESTERONE IN HUMAN PLASMA DURING PREGNANCY AND THE MENSTRUAL CYCLE

1962 ◽  
Vol 25 (2) ◽  
pp. 239-244 ◽  
Author(s):  
R. V. SHORT ◽  
IRIS LEVETT
Keyword(s):  
Menstrual Cycle ◽  
Pregnant Women ◽  
Human Plasma ◽  
Peripheral Blood ◽  
Luteal Phase ◽  
Follicular Phase ◽  
Fluorimetric Determination ◽  
Fluorescence Reaction ◽  
Good Agreement

SUMMARY The fluorescence reaction for progesterone described by Touchstone & Murawec (1960) has been used to determine the concentration of progesterone in nineteen samples of peripheral blood from pregnant women, and in seventeen samples of peripheral blood from women during the course of the menstrual cycle. There was good agreement between the ultraviolet and fluorescent estimates of progesterone in all the samples from pregnant women. The concentrations found during the follicular phase of the menstrual cycle were in general lower than those found during the luteal phase. In one woman who was sampled repeatedly during the course of a menstrual cycle, there was a well defined rise in the level of progesterone in the blood after the expected date of ovulation.

scholarly journals Effects of hyperandrogenemia and increased adiposity on reproductive and metabolic parameters in young adult female monkeys

2014 ◽  
Vol 306 (11) ◽  
pp. E1292-E1304 ◽  
Author(s):  
W. K. McGee ◽  
C. V. Bishop ◽  
C. R. Pohl ◽  
R. J. Chang ◽  
J. C. Marshall ◽  
...  
Keyword(s):  
Luteal Phase ◽  
Polycystic Ovary ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Follicular Phase ◽  
Antral Follicles ◽  
Reproductive Axis ◽  
Early Follicular Phase ◽  
Follicular Size ◽  
Cholesterol Control

Many patients with hyperandrogenemia are overweight or obese, which exacerbates morbidities associated with polycystic ovary syndrome (PCOS). To examine the ability of testosterone (T) to generate PCOS-like symptoms, monkeys received T or cholesterol (control) implants ( n = 6/group) beginning prepubertally. As previously reported, T-treated animals had increased neuroendocrine drive to the reproductive axis [increased luteinizing hormone (LH) pulse frequency] at 5 yr, without remarkable changes in ovarian or metabolic features. To examine the combined effects of T and obesity, at 5.5 yr (human equivalent age: 17 yr), monkeys were placed on a high-calorie, high-fat diet typical of Western cultures [Western style diet (WSD)], which increased body fat from <2% (pre-WSD) to 15–19% (14 mo WSD). By 6 mo on WSD, LH pulse frequency in the controls increased to that of T-treated animals, whereas LH pulse amplitude decreased in both groups and remained low. The numbers of antral follicles present during the early follicular phase increased in both groups on the WSD, but maximal follicular size decreased by 50%. During the late follicular phase, T-treated females had greater numbers of small antral follicles than controls. T-treated monkeys also had lower progesterone during the luteal phase of the menstrual cycle. Although fasting insulin did not vary between groups, T-treated animals had decreased insulin sensitivity after 1 yr on WSD. Thus, while WSD consumption alone led to some features characteristic of PCOS, T + WSD caused a more severe phenotype with regard to insulin insensitivity, increased numbers of antral follicles at midcycle, and decreased circulating luteal phase progesterone levels.

Cortisol, 17α-OH-progesterone and androgen responses to a standardized ACTH-stimulation in different stages of the normal menstrual cycle

1982 ◽  
Vol 100 (3) ◽  
pp. 427-433 ◽  
Author(s):  
N. Kruyt ◽  
R. Rolland
Keyword(s):  
Menstrual Cycle ◽  
Luteal Phase ◽  
Follicular Phase ◽  
Adrenal Hyperplasia ◽  
Acth Stimulation Test ◽  
Normal Range ◽  
Acth Stimulation ◽  
Normal Menstrual Cycle ◽  
Early Follicular Phase ◽  
Three Stages

Abstract. The release of cortisol, 17α-OH-progesterone, androstenedione and testosterone during a standardized ACTH-stimulation test was investigated in three different stages of the normal menstrual cycle, to conclude if there is any stage dependency on the release of these hormones. No statistically significant differences were observed between the three stages concerning cortisol and testosterone increase. The increase of androstenedione in the pre-ovulatory stage was significantly higher than that seen during the early follicular phase of the cycle. The increase of 17α-OH-progesterone in the luteal phase was significantly less than that of both the early and late follicular stages of the cycle. Progesterone levels showed a small, but significant increase after ACTH-stimulation, in both the early and late stage of the follicular phase. However, the levels remained within the normal range of the follicular phase. In the luteal phase no increase was seen after ACTH-stimulation. Oestradtiol-17β levels did not change at all after ACTH-stimulation. The stage dependency of androstenedione and 17α-OH-progesterone is discussed. The described stage-dependency different increase of 17α-OH-progesterone release can be of importance when the results of ACTH-tests are evaluated to detect carriers of congenital adrenal hyperplasia.

PITUITARY AND OVARIAN HORMONAL RESPONSE TO 48 h GONADOTROPHIN RELEASING HORRMONE (GnRH) INFUSIONS IN FEMALE RHESUS MONKEYS

1978 ◽  
Vol 89 (1) ◽  
pp. 48-59 ◽  
Author(s):  
M. Ferin ◽  
J. Bogumil ◽  
J. Drewes ◽  
I. Dyrenfurth ◽  
R. Jewelewicz ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Luteal Phase ◽  
Rhesus Monkeys ◽  
Fold Increase ◽  
Follicular Phase ◽  
Lh Surge ◽  
Entire Duration ◽  
Female Rhesus ◽  
Early Follicular Phase ◽  
Late Follicular Phase

ABSTRACT The effects of prolonged gonadotrophin-releasing hormone (GnRH) infusions on LH, FSH, oestrogens and progesterone secretion were studied in female rhesus monkeys at various times of the menstrual cycle and after castration. GnRH was infused at the rate of 15 μg/h for 48 h. This resulted in mean peripheral GnRH levels of 398 ± 31.5 pg/ml (± se) as measured by radioimmunoassay. As expected the pattern of gonadotrophin responses to GnRH varied considerably with the phase of the menstrual cycle. The largest LH increase was seen during the late follicular phase (6-fold over baseline), with a 3-fold increase during the luteal phase and a 2-fold one during the early follicular phase and in the period following the LH surge. Significant FSH increases (4-fold) were seen only during the follicular phase. Oestrogens increased about 2-fold within 4 h of the start of the infusion during the early follicular phase. In the late follicular phase and during the LH surge, they declined within 24 and 1 h, respectively. Large progesterone increases were seen only during the luteal phase. Of special interest is the fact that the increase in gonadotrophin secretion could not be maintained for the entire duration of the experiment even though GnRH continued to be infused at rates sufficient to elicit initial increases of several fold over baseline. Gonadotrophin release declined 4–28 h after the initial stimulation. A further decrease below pre-infusion control levels was particularly evident during the midcycle surge and, for FSH, after ovariectomy. These results indicate that a continuous mode of administration may rapidly induce a desensitization phenomenon at the level of the gonadotroph.

scholarly journals Soy Isoflavones Exert Modest Hormonal Effects in Premenopausal Women1

1999 ◽  
Vol 84 (1) ◽  
pp. 192-197 ◽  
Author(s):  
Alison M. Duncan ◽  
Barbara E. Merz ◽  
Xia Xu ◽  
Theodore C. Nagel ◽  
William R. Phipps ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Luteal Phase ◽  
Weight Control ◽  
Control Diet ◽  
Premenopausal Women ◽  
Dehydroepiandrosterone Sulfate ◽  
Follicular Phase ◽  
Soy Isoflavones ◽  
Sex Hormone Binding Globulin ◽  
Early Follicular Phase

Soy isoflavones are hypothesized to be responsible for changes in hormone action associated with reduced breast cancer risk. To test this hypothesis, we studied the effects of isoflavone consumption in 14 premenopausal women. Isoflavones were consumed in soy protein powders and provided relative to body weight (control diet, 10 ± 1.1; low isoflavone diet, 64 ± 9.2; high isoflavone diet, 128 ± 16 mg/day) for three menstrual cycles plus 9 days in a randomized cross-over design. During the last 6 weeks of each diet period, plasma was collected every other day for analysis of estrogens, progesterone, LH, and FSH. Diet effects were assessed during each of four distinctly defined menstrual cycle phases. Plasma from the early follicular phase was analyzed for androgens, cortisol, thyroid hormones, insulin, PRL, and sex hormone-binding globulin. The low isoflavone diet decreased LH (P = 0.009) and FSH (P = 0.04) levels during the periovulatory phase. The high isoflavone diet decreased free T3 (P = 0.02) and dehydroepiandrosterone sulfate (P = 0.02) levels during the early follicular phase and estrone levels during the midfollicular phase (P = 0.02). No other significant changes were observed in hormone concentrations or in the length of the menstrual cycle, follicular phase, or luteal phase. Endometrial biopsies performed in the luteal phase of cycle 3 of each diet period revealed no effect of isoflavone consumption on histological dating. These data suggest that effects on plasma hormones and the menstrual cycle are not likely to be the primary mechanisms by which isoflavones may prevent cancer in premenopausal women.

scholarly journals Effect of immunization against the alpha N (alphaN) and alpha C (alphaC) peptides of the alpha43 subunit of inhibin on antral follicular growth and atresia and the patterns of gonadotrophin secretion in ewes

Reproduction ◽  
2001 ◽  
pp. 707-718 ◽  
Author(s):  
A Dhar ◽  
BW Doughton ◽  
E Pruysers ◽  
RW Brown ◽  
JK Findlay
Keyword(s):  
Follicular Phase ◽  
Corpora Lutea ◽  
Follicular Growth ◽  
Antral Follicles ◽  
Gonadotrophin Secretion ◽  
Preovulatory Follicles ◽  
Early Follicular Phase ◽  
The Mean ◽  
And Control

The aims of this study were to investigate the role of inhibin in the distribution of healthy and atretic antral follicles and the secretion patterns of gonadotrophins. Ewes were actively immunized against either alphaN or alphaC of the inhibin alpha subunit with a primary injection and three booster injections. The control ewes received adjuvant only. The ovaries were removed either before or at 24 h after hCG administration in a synchronized follicular phase 48 h after removal of intravaginal progesterone pessaries. Morphological observations were made on every fifth section of the complete ovary (one per ewe) stained with haematoxylin and eosin. The mean number of corpora lutea observed per ewe with corpora lutea was not significantly different in ewes immunized against alphaN (2.4; alphaN-immunized ewes) or alphaC (2.6; alphaC-immunized ewes), and control (2.4) ewes, although some corpora lutea appeared cystic in the immunized ovaries. Compared with luteal phase concentrations, mean basal FSH concentrations in the early follicular phase were significantly increased in the alphaC-immunized ewes, similar in alphaN-immunized ewes and reduced in control ewes. No differences were observed in any of the LH parameters. Before hCG treatment, healthy antral follicles > 1 mm in diameter were not observed in any of the 52 follicles in the aC-immunized ewes and were observed in one of 37 follicles from alphaN-immunized ewes compared with 19 of 28 follicles in control ewes (P < 0.0001). For healthy antral follicles < 1 mm in diameter, there were 72 of 85 follicles in the alphaC-immunized ewes, 79 of 81 follicles in the alphaN-immunized ewes and 81 of 82 follicles in the control ewes. Similar results were obtained in healthy antral follicles < 1 mm in diameter at 24 h after hCG administration. In contrast to the control ewes, no healthy preovulatory follicles (> 6 mm in diameter) were observed in alphaN- and alphaC-immunized ewes either before or 24 h after hCG administration. Two newly formed corpora lutea from alphaC-immunized ovaries contained retained oocytes compared with none in control and alphaN-immunized ovaries. In conclusion, immunization against alphaN and alphaC may result in disruption of the normal processes of antral follicular growth and maturation independent of the concentrations of FSH and LH.

SECRETION OF BIOACTIVE INHIBIN BY THE OVARY OF THE BOOROOLA MERINO EWE WITH OR WITHOUT A COPY OF THE FECUNDITY (F) GENE.

1988 ◽  
Vol 119 (1) ◽  
pp. R5-R8 ◽  
Author(s):  
C. G. Tsonis ◽  
D. T. Baird ◽  
B. K. Campbell ◽  
J. A. Downing ◽  
R. J. Scaramuzzi
Keyword(s):  
Luteal Phase ◽  
Follicular Phase ◽  
Pituitary Cells ◽  
F Gene ◽  
Progesterone Secretion ◽  
Early Follicular Phase ◽  
Late Follicular Phase ◽  
Secretion Rates ◽  
Sampling Times ◽  
Low Rate

ABSTRACT The secretion rates of bioactive inhibin, oestradiol and progesterone were measured during the mid-luteal phase and at various times during the follicular phase of the cycle by a sensitive bioassay using sheep pituitary cells in culture in 12 Booroola ewes with and without copies of the Fecundity (F) gene in which the left ovary had been auto-transplanted to the neck. Inhibin secretion was high during the luteal phase and fell in the early follicular phase in all genotypes (P < 0.01). In Booroola ewes with a F/- genotype, inhibin secretion then increased again, towards luteal rates, in the mid and late follicular phases. In Booroola ewes without a copy of the F gene (+/+) inhibin secretion remained low at all three sampling times in the follicular phase. The secretion rate of inhibin at 36 h (P < 0.1) and 48 h (P < 0.01) were significantly lower in ewes from the +/+ (no copy of the gene) ewes than in F/(one copy of the gene) ewes. Oestradiol secretion was low during the luteal phase and increased steadily during the early (24 h) to a plateau in the mid (36 h; P < 0.01) and late (48 h; P < 0.05) follicular phase. Progesterone secretion was high during the luteal phase, and decreased to a very low rate by 24 h after prostaglandin (PG) treatment (P < 0.001) and remained low. At 24 h after PG the concentration of FSH was significantly lower (P < 0.01) than that during the luteal phase and remained suppressed until the onset of the LH surge. There were no significant differences in LH concentrations. We conclude that (1) the secretion of inhibin by the ovary is highest in the luteal phase and (2) inhibin secretion is significantly raised during the mid to late follicular phase in Booroola ewes with a copy of the Fecundity gene compared with those without.

Pulsatile secretion of inhibin, oestradiol and androstenedione by the ovary of the sheep during the oestrous cycle

1990 ◽  
Vol 126 (3) ◽  
pp. 385-393 ◽  
Author(s):  
B. K. Campbell ◽  
G. E. Mann ◽  
A. S. McNeilly ◽  
D. T. Baird
Keyword(s):  
Luteal Phase ◽  
Venous Blood ◽  
Pulse Amplitude ◽  
Pulse Frequency ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Blood Samples ◽  
Early Follicular Phase ◽  
Lh Secretion ◽  
Late Follicular Phase

ABSTRACT The pattern of pulsatile secretion of inhibin, oestradiol and androstenedione by the ovary at different stages of the oestrous cycle in sheep was studied in five Finn–Merino ewes in which the left ovary had been autotransplanted to the neck. The ewes had jugular venous blood samples collected at 4-hourly intervals from 42 h before the induction of luteolysis by i.m. injection of cloprostenol (100 μg) on day 10 of the oestrous cycle, until day 3 of the following cycle. There were five periods of intensive blood sampling, when both ovarian and jugular venous blood samples were collected, as follows: (a) mid-luteal phase, before the second injection of cloprostenol on day 10 (15-min intervals for 6 h); (b) early follicular phase, 24 h after the second injection of cloprostenol (10-min intervals for 4 h); (c) late follicular phase, 48 h after the second injection of cloprostenol (10-min intervals for 4 h); (d) after the LH surge on day 1 of the cycle, 76 h after the second injection of cloprostenol (10-min intervals for 4 h); (e) early luteal phase on day 3 of the cycle, 120 h after the second injection of cloprostenol (10-min intervals for 3 h). Plasma was collected and the samples assayed for LH, FSH, progesterone, oestradiol, androstenedione and inhibin. The ovarian secretion rates for oestradiol, androstenedione and inhibin were calculated. All ewes responded normally to the luteolytic dose of cloprostenol with the preovulatory surge of LH occurring within 56·4±1·6 h (mean ± s.e.m.) followed by the establishment of a normal luteal phase. The pulse frequency of LH, oestradiol and androstenedione increased in the transition from the luteal to the follicular phase (P<0·01). On day 1 of the cycle LH secretion consisted of low-amplitude high-frequency pulses (1·0±0·1 pulse/h) to which androstenedione, but not oestradiol, responded. On day 3 of the cycle LH secretion was similar to that on day 1 but both androstenedione and oestradiol secretion were pulsatile in response to LH, indicating the presence of oestrogenic follicles. The stage of the cycle had no significant effects on LH pulse amplitude and nadir but the ovarian secretory response to LH stimulation did vary with the stage of the cycle. Prolactin pulse frequency, amplitude and nadir were higher (P<0·05) during the follicular phase than the luteal phase. Prolactin pulse frequency was depressed (P<0·05) on day 1 of the cycle but increased to follicular phase levels on day 3. Prolactin pulse frequency was significantly correlated to oestradiol pulse frequency (r = 0·54; P<0·01). During the luteal phase there were insufficient oestradiol pulses to obtain an estimate of pulse amplitude and nadir but both these parameters reached their highest level during the late follicular phase, fell to negligible levels on day 1 and increased to early follicular phase levels on day 3. Androstenedione pulse amplitude and nadir exhibited similar but less marked variation. Inhibin secretion was episodic at all stages of the cycle examined but did not exhibit significant variation with stage of cycle in any of the parameters of episodic secretion measured. Inhibin pulses were not related to either LH or prolactin at any stage of the cycle. FSH secretion was not detectably pulsatile but jugular venous concentrations of FSH at each stage of the oestrous cycle were negatively correlated with mean oestradiol (r= −0·52; P<0·01 but not inhibin secretion (r = 0·19). We conclude that (i) LH secretion is pulsatile at all stages of the oestrous cycle but the steroidogenic responses of the ovary varies with the stage of the cycle, reflecting changes in characteristics of the follicle population, (ii) ovarian inhibin secretion is episodic and displays little change with the stage of the oestrous cycle and (iii) episodic inhibin secretion is not related to either pulses of LH or prolactin. The aetiology of these inhibin pulses therefore remains unknown. Journal of Endocrinology (1990) 126, 385–393

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