EFFECT OF α-MSH ON PLASMA LEVELS OF LH, FSH, PROGESTERONE AND CORTISOL DURING THE CORPUS LUTEUM PHASE OF THE MENSTRUAL CYCLE

1976 ◽  
Vol 81 (1) ◽  
pp. 243-251 ◽  
Author(s):  
B. Runnebaum ◽  
J. Heep ◽  
W. Geiger ◽  
P. Vecsei ◽  
J. Andor
Keyword(s):  
Menstrual Cycle ◽  
Corpus Luteum ◽  
Plasma Levels ◽  
Plasma Cortisol ◽  
Plasma Concentrations ◽  
Fold Increase ◽  
Blood Levels ◽  
Peripheral Plasma ◽  
Intravenous Infusions ◽  
Dose Dependent

ABSTRACT In healthy women (21–28 years) the influence of synthetic α-MSH upon the peripheral plasma levels of LH, FSH, progesterone and cortisol was determined during the corpus luteum phase of the menstrual cycle. As controls 3 women were given 6 intravenous infusions of 250 ml NaCl; 4 women received a total of 18 intravenous infusions of 5–20 mg α-MSH from 9.00 to 11.00 a. m. on the 5th and 7th hyperthermic day of the menstrual cycle. The blood levels of the hormones were usually followed for 24 h, and in two cases for 48 h. During and after the control as well as the experimental infusions with 5–20 mg α-MSH, no significant changes in the plasma concentrations of LH, FSH and progesterone were found. The cortisol concentrations, however, showed on the average a 2-fold increase over the initial values during the infusion of 5 mg and 10 mg α-MSH. During the control infusions they were not enhanced. One experiment was conducted with 20 mg α-MSH. The increase in the plasma cortisol levels following α-MSH administration generally seemed to be dose dependent, but statistically no significant differences regarding the increase in cortisol level could be detected between the 5 mg and 10 mg doses.

Effect of adrenalectomy on the regulation of the secretion of gonadotrophins and prolactin in the lactating rat

1983 ◽  
Vol 98 (2) ◽  
pp. 227-232 ◽  
Author(s):  
P. van der Schoot ◽  
W. J. de Greef
Keyword(s):  
Plasma Levels ◽  
Inhibitory Action ◽  
Adrenal Glands ◽  
Marked Effect ◽  
Plasma Concentrations ◽  
Inhibitory Effect ◽  
Blood Levels ◽  
Adrenal Hormones ◽  
Adrenocortical Hormones ◽  
Adrenalectomized Rats

The suckling stimulus exerts an inhibitory action on the release of gonadotrophins during lactation. The possible involvement of the adrenal glands in this process was examined by studying the plasma levels of gonadotrophins in lactating rats ovariectomized on the day after parturition. It appeared that the suppression, throughout suckling, of the rise in levels of gonadotrophins in blood after ovariectomy occurred to the same extent in adrenalectomized and in sham-operated animals. It thus seems unlikely that adrenocortical hormones, albeit secreted in larger quantities during lactation, exert an inhibitory effect on the release of gonadotrophins. Adrenalectomy had a marked effect on the plasma concentrations of prolactin during the second half of lactation. Whereas plasma concentrations of prolactin in the first half of lactation were similar in adrenalectomized and sham-operated rats, the concentrations in adrenalectomized rats did not undergo the reduction found in sham-operated rats. Adrenal hormones may thus be involved in the reduction of blood levels of prolactin observed in rats and in other mammals as lactation progresses.

Effect of pinealectomy on the plasma concentrations of prolactin, cortisol and testosterone in sheep in short and skeleton long photoperiods

1984 ◽  
Vol 100 (3) ◽  
pp. 287-294 ◽  
Author(s):  
B. R. Brinklow ◽  
J. M. Forbes
Keyword(s):  
Plasma Levels ◽  
Plasma Cortisol ◽  
Plasma Concentrations ◽  
Plasma Prolactin ◽  
Long Photoperiod

ABSTRACT Two experiments were carried out to investigate the effects of pinealectomy on the responses of prolactin, cortisol and testosterone to skeleton long photoperiods (7 h light: 10 h darkness: 1 h light: 6 h darkness; 7L: 10D: 1L: 6D) compared with short photoperiods (8L: 16D) in lambs. The first experiment included 23 female Suffolk cross sheep aged 10 months, of which six were pinealectomized. The skeleton long photoperiod significantly increased plasma levels of prolactin but this was blocked by pinealectomy; there was a peak around dusk and a trough around dawn and at the time of the 1-h period of light. There was no effect of either photoperiod or pinealectomy on plasma levels of cortisol. Testosterone was not measured in this experiment. In the second experiment there were 12 intact males and 11 castrated males aged 3 months; six of the lambs in each group were pinealectomized. Prolactin was again greatly stimulated by skeleton long photoperiods and the effect was blocked by pinealectomy; there was a trough in plasma prolactin at dawn in all groups. In addition, castration increased prolactin levels on two of the four sampling days. Plasma cortisol concentrations were significantly lower under skeleton long photoperiods and this was also blocked by pinealectomy; there was no effect of castration. Testosterone was much higher in intact males. After 10 weeks of exposure, skeleton long photoperiods produced significantly lower concentrations than short photoperiods in the intact ram with pineal glands but not in those which were pinealectomized. J. Endocr. (1984) 100, 287–294

THE SITE OF SECRETION OF ANDROSTENEDIONE IN NON-PREGNANT WOMEN

1974 ◽  
Vol 63 (1) ◽  
pp. 201-212 ◽  
Author(s):  
D. T. BAIRD ◽  
P. E. BURGER ◽  
G. D. HEAVON-JONES ◽  
R. J. SCARAMUZZI
Keyword(s):  
Menstrual Cycle ◽  
Pregnant Women ◽  
Corpus Luteum ◽  
Luteal Phase ◽  
Peripheral Plasma ◽  
Ovulatory Follicle ◽  
Reproductive Life ◽  
Cellular Compartments ◽  
Venous Plasma

SUMMARY The site of secretion of androstenedione in women was investigated by measuring the concentration of androstenedione in peripheral and ovarian venous plasma by radioimmunoassay at different stages of the menstrual cycle. The concentration in peripheral plasma rose from 1·45 ± 0·11 (s.e.m.) ng/ml on day 1 to a peak on the 7 days around mid-cycle (2·29 ± 0·08) before declining gradually during the luteal phase. The concentration of androstenedione in plasma draining ovaries containing the pre-ovulatory follicle or a corpus luteum (33·2 ± 9·0) was significantly higher than in plasma draining the contralateral ovary (10·1 ± 1·6, P < 0·001). In women in whom ovulation was induced with gonadotrophins the concentration of androstenedione in peripheral plasma rose from 1·42 ± 0·21 before treatment to reach maximum levels (2·5–4·5 ng/ml) in the luteal phase. There was a significant (P < 0·001) correlation between the concentration of androstenedione and oestradiol-17β in peripheral (r = 0·50) and ovarian (r = 0·79) venous plasma. These findings indicate that all three cellular compartments in the ovary secrete significant amounts of androstenedione in women during their reproductive life.

Evidence for episodic but not circadian activity in plasma concentrations of adrenocorticotrophin, cortisol and thyroxine in dogs

1984 ◽  
Vol 103 (2) ◽  
pp. 219-226 ◽  
Author(s):  
R. J. Kemppainen ◽  
J. L. Sartin
Keyword(s):  
Plasma Levels ◽  
Plasma Concentrations ◽  
Fold Increase ◽  
Sampling Period ◽  
Peak Frequency ◽  
Plasma Samples ◽  
Circadian Activity ◽  
Apparent Increase ◽  
The Mean ◽  
Cortisol Levels

ABSTRACT Concentrations of immunoreactive (i) ACTH, cortisol and thyroxine were determined in plasma samples obtained at 20-min intervals for 25 h in nine normal and two adrenalectomized dogs. The dogs were exposed to a 12 h light:12 h darkness photoperiod for 30 days before the sampling period. Episodic secretion of iACTH and cortisol was evident in each normal dog, with an average of 9·0 iACTH peaks and 10·1 cortisol peaks in a 24-h period. Levels of iACTH and cortisol were significantly correlated in each normal dog, but periods of dissociation between levels of the two hormones were apparent. A sex difference in 24-h mean iACTH and cortisol levels, numbers of cortisol peaks, and amplitude of iACTH peaks was observed, with females showing higher mean levels and greater peak frequency and amplitude in each instance. Adrenalectomy resulted in a 50- to 150-fold increase in mean iACTH concentrations with an apparent increase in iACTH peak amplitude. Cortisol levels were unchanging in the adrenalectomized dogs. Thyroxine concentrations showed episodic variation in each of the normal dogs, but the mean number of peaks (3·3/24-h period) was considerably less than for iACTH or cortisol. Female dogs had significantly higher 24-h mean levels of thyroxine than did males. No circadian rhythmicity was obvious for the plasma levels of any of the three hormones measured. J. Endocr. (1984) 103, 219–226

Peripheral plasma concentrations of pregnenolone sulphate, pregnenolone, progesterone and 20α-hydroxy-4-pregnen-3-one in ewes throughout the oestrous cycle

1987 ◽  
Vol 113 (2) ◽  
pp. 231-237 ◽  
Author(s):  
S. A. McKay ◽  
G. Jenkin ◽  
G. D. Thorburn
Keyword(s):  
Plasma Concentration ◽  
Corpus Luteum ◽  
Plasma Concentrations ◽  
Oestrous Cycle ◽  
Positive Correlation ◽  
Peripheral Plasma

ABSTRACT Pregnenolone sulphate, pregnenolone, progesterone and 20α-hydroxy-4-pregnen-3-one concentrations in peripheral plasma of normal cyclic ewes were measured by radioimmunoassay. The concentrations of these steroids were correlated with that of progesterone. The concentrations of all the steroids measured in peripheral plasma varied in a cyclic manner and showed a significant (P <0·05) positive correlation with the concentration of progesterone. Peripheral plasma concentrations of these steroids in ovariectomized and ovariectomized, dexamethasone-treated ewes were also determined. The plasma concentration of progesterone in ovariectomized ewes was undetectable but the concentrations of pregnenolone sulphate, pregnenolone and 20α-hydroxy-4-pregnen-3-one remained similar to those observed at oestrus. Administration of dexamethasone to ovariectomized ewes had no effect on pregnenolone sulphate or pregnenolone concentrations but 20α-hydroxy-4-pregnen-3-one concentrations, which were already very low, decreased further. It is proposed that the ovary, probably the corpus luteum, secretes pregnenolone sulphate, pregnenolone and 20α-hydroxy-4-pregnen-3-one; however, pregnenolone sulphate and 20α-hydroxy-4-pregnen-3-one may also arise from the metabolism of circulating pregnenolone and progesterone. J. Endocr. (1987) 113, 231–237.

PROGESTERONE CONCENTRATIONS IN MATERNAL AND FOETAL BLOOD PLASMA OF EWES

1972 ◽  
Vol 53 (2) ◽  
pp. 187-194 ◽  
Author(s):  
N. W. MOORE ◽  
SUSAN BARRETT ◽  
J. B. BROWN
Keyword(s):  
Protein Binding ◽  
Blood Plasma ◽  
Corpus Luteum ◽  
Plasma Levels ◽  
Umbilical Vein ◽  
Peripheral Plasma ◽  
Active Ovary ◽  
Competitive Protein Binding ◽  
Foetal Blood

SUMMARY In pregnant ewes the progesterone concentrations in plasma from the maternal jugular, ovarian (active ovary) and uterine veins and from the foetal umbilical vein were measured by a competitive protein-binding technique. Peripheral plasma levels remained fairly uniform throughout pregnancy, whereas ovarian levels dropped at about the 130th day of pregnancy. Uterine plasma levels were low until the 80th day; foetal levels rose as pregnancy progressed. The major sources of progesterone appeared to be the ovary (corpus luteum) and the uterus (placenta). The ovarian contribution was greater during the first two-thirds of pregnancy than later, whereas that made by the placenta was lower during the first one-third of pregnancy.

PERIPHERAL PLASMA LEVELS OF 17α-HYDROXYPROGESTERONE, PROGESTERONE AND OESTRADIOL DURING NORMAL MENSTRUAL CYCLES IN WOMEN

1972 ◽  
Vol 71 (4) ◽  
pp. 743-754 ◽  
Author(s):  
Tore H:son Holmdahl ◽  
Elof D. B. Johansson
Keyword(s):  
Menstrual Cycle ◽  
Plasma Levels ◽  
Luteal Phase ◽  
Cycle Length ◽  
Gel Chromatography ◽  
Blood Samples ◽  
Menstrual Cycles ◽  
Peripheral Plasma ◽  
Competitive Protein Binding ◽  
Human Menstrual Cycle

ABSTRACT Liquid-gel chromatography on hydroxyalkoxypropyl Sephadex has been used to separate 17α-hydroxyprogesterone* and progesterone from interfering steroids prior to assay by competitive protein binding. During the luteal phase 0.5 ml of plasma was enough for determinations of both steroids. Fifteen samples could be assayed in less than 48 h. Oestradiol in plasma was assayed by radioimmunoassay. Daily blood samples were collected during 10 normal menstrual cycles in young, healthy women. The average cycle length was 29.7±2.0 (sd) days. 17α-hydroxyprogesterone displayed a midcyclic peak averaging 1.86±0.70 (sd) ng per ml coinciding with a midcyclic peak of oestradiol averaging 16.50± 5.95 (sd) ng per 100 ml of plasma. The highest luteal phase level of 17α-hydroxyprogesterone was 1.94 ±0.72 (sd) ng per ml. The corresponding levels for oestradiol were 9.1 ±3.8 (sd) ng per 100 ml. Progesterone formed a luteal plateau averaging 12.3±2.3 (sd) days. The highest luteal level of progesterone was 14.6±2.1 (sd) ng per ml. The peripheral plasma pattern of 17α-hydroxyprogesterone seems to mimic that of oestradiol during the human menstrual cycle.

DOSE-RESPONSE STUDY WITH A NEW LH-RH ANALOGUE, D-Ser (TBU)6 LH-RH 1–9 (EA)10 DURING THE FOLLICULAR PHASE OF THE MENSTRUAL CYCLE

1978 ◽  
Vol 87 (1) ◽  
pp. 19-27 ◽  
Author(s):  
E. Friedrich ◽  
A. Etzrodt ◽  
H. Becker ◽  
J. P. Hanker ◽  
E. Keller ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Plasma Concentrations ◽  
Relative Increase ◽  
Follicular Phase ◽  
Dependent Effect ◽  
Treatment Groups ◽  
Highly Active ◽  
Lh Rh ◽  
Dose Dependent ◽  
Dose Dependent Effect

ABSTRACT D-Ser (TBU)6 LH-RH 1–9 (EA)10 (HOE 766) a highly active LH-RH analogue, was studied with regard to its effects on the release of follicle stimulating hormone (FSH), luteinizing hormone (LH) and oestradiol-17β (Oe2) during the follicular phase of the menstrual cycle. Forty-two regularly menstruating women were allowed to five different treatment groups with different doses (1.25 μg; 2.5 μg; 5.0 μg; 10.0 μg; 20.0 μg) of HOE 766 given as intravenous bolus injections and the plasma concentrations of FSH, LH and Oe2 were measured up to 24 h after injection using specific radioimmunoassays. In the majority of cases, peak values of both FSH and LH occurred 4 h after injection being significantly different from pre-injection levels (P < 0.02 in the 1.25 μg treatment group, P < 0.005 for the other treatment groups). Statistical analysis of maximum values as well as the absolute and relative increase in the different treatment groups revealed a dose-dependent effect of HOE 766. Maximum values of Oe2 occurred 8 h after injection and were found to be significantly different from pre-injection levels (P < 0.005). However, no dose dependent effect was observed. It was concluded that HOE 766 is a potent and long-acting stimulator of FSH, LH and Oe2 release in women. The effect of HOE 766 is dose dependent for FSH and LH but not for Oe2.

CORRELATION OF REVERSE-T3 AND 3,3′-T2 (T2′) PLASMA CONCENTRATIONS UNDER PHYSIOLOGICAL AND EXPERIMENTAL CONDITIONS IN MAN

1978 ◽  
Vol 89 (4) ◽  
pp. 679-686 ◽  
Author(s):  
M. Hüfner ◽  
M. Grussendorf
Keyword(s):  
Plasma Levels ◽  
Plasma Concentrations ◽  
Blood Levels ◽  
Experimental Conditions ◽  
Reverse T3 ◽  
Physiological Conditions ◽  
Minor Degree ◽  
A Minor ◽  
Therapeutic Doses ◽  
Normal Adults

ABSTRACT T2′ plasma levels are measured under different conditions and correlated to the respective rT3 concentrations. Specific RIAs for T2′ and rT3 are used. Pharmacological doses of T3 cause an increase of plasma T2′; if T3 or T4 doses are administered to an athyroid patient which cause a similar level of plasma T3 the increase of T2′ is much larger during T4 treatment. Cord blood levels of T2′ are 2–3-fold higher than in normal adults whereas rT3 concentrations are about 10 times higher than normal. After birth rT3 and T2′ levels decrease in about a parallel manner. After a bolus iv injection of 500 μg rT3, T2′ starts to increase as early as 2 min after injection. PTU in therapeutic doses causes a rapid increase of plasma rT3 with a maximum 4 h after ingestion. A dose of 150 mg PTU causes a maximum of about 100% above baseline. T2′ also increases but to a lesser degree (about 50 % above baseline). We conclude that rT3 is the most important precursor of T2′ whereas T3 contributes only to a minor degree to the total T2′ production under physiological conditions.

Variations in plasma motilin, somatostatin, and pancreatic polypeptide concentrations and the interdigestive myoelectric complex in dog

1985 ◽  
Vol 63 (12) ◽  
pp. 1495-1500 ◽  
Author(s):  
P. Poitras ◽  
M. Lemoyne ◽  
D. Tasse ◽  
L. Trudel ◽  
T. Y. Yamda ◽  
...  
Keyword(s):  
Pancreatic Polypeptide ◽  
Plasma Levels ◽  
Intestinal Motility ◽  
Plasma Concentrations ◽  
Statistical Correlation ◽  
Significant Rise ◽  
Phase Iii ◽  
Blood Levels ◽  
Plasma Motilin ◽  
Related Increase

We have looked at the plasma concentrations of motilin, pancreatic polypeptide (PP), and somatostatin (STS) during the various phases of the interdigestive motor complex (IDMC) in dogs. As expected, motilin cyclical increase was always associated with the phase III of the IDMC. Statistical analysis of PP variations revealed a significant rise 10 min before duodenal phase III; however, in individual animals, this relationship was inconsistent. Although a dose-related increase in PP blood levels was induced by administration of synthetic canine motilin (0–200 ng kg−1 iv), fasting plasma levels of PP were not correlated with the concentrations of circulating endogenous motilin. After truncal vagotomy, while motilin release and the intestinal motility pattern remained unaltered, the phase III associated cyclical increases of PP disappeared. Infusion of physiological amounts of PP (1 μg kg−1 h−1 for 3 h) mimicking the postprandial release failed to reproduce a fed pattern type of intestinal motility and of motilin secretion. No statistical correlation could be established between STS plasma levels and the motor activity of the intestine. STS plasma levels were not correlated with circulating concentrations of motilin and the exogenous administration of physiological doses of synthetic canine motilin failed to modify STS plasma levels. Morphine (200 μg kg−1 iv) stimulated only the release of motilin. These data suggest that the role played by circulating concentrations of PP and STS in the control of the IDMC in dog is at most minimal.

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