INFLUENCE OF SUCKLING AND OF SUCKLING FOLLOWED BY TRH OR LH-RH ON PLASMA PROLACTIN, TSH, GH AND FSH

1976 ◽  
Vol 82 (1) ◽  
pp. 246-253 ◽  
Author(s):  
S. Jeppsson ◽  
K. O. Nilsson ◽  
G. Rannevik ◽  
L. Wide
Keyword(s):  
Limit Of Detection ◽  
Post Partum ◽  
Prolactin Secretion ◽  
Plasma Prolactin ◽  
Additional Increase ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Before And After ◽  
Plasma Gh ◽  
Lh Rh

ABSTRACT Ten women were studied during the first post-partum week. Suckling for 20 min induced a marked increase in plasma prolactin, reaching a maximum within 0–25 min after the end of suckling and then returning to pre-suckling levels after 120 min. Suckling induced no changes in plasma thyrotrophin (TSH), growth hormone (GH) or follicle stimulating hormone (FSH). The iv injection of 200 μg of thyrotrophin releasing hormone (TRH) immediately after suckling resulted in an additional increase in plasma prolactin and a rise in TSH. When given 120 min after suckling TRH was followed by increased plasma levels of prolactin and TSH, which for both hormones were of a magnitude comparable to the TRH induced increment seen immediately after suckling. Thus, suckling did not inhibit the effect of TRH on the release of TSH. These studies indicate that TRH is probably not involved in the suckling induced increase in prolactin secretion. The mean plasma FSH level was below the limit of detection before and after suckling. Neither plasma FSH nor prolactin showed any appearant changes following the iv injection of 25 μg of luteinizing hormone releasing hormone (LH-RH), when given immediately after and 120 min after suckling. When given after suckling as indicated above, TRH induced no changes in plasma GH or FSH and similarly LH-RH was without influence on plasma GH and TSH.

PITUITARY HORMONE RESPONSES TO HYPOTHALAMIC RELEASING HORMONES IN ACROMEGALY

1976 ◽  
Vol 83 (4) ◽  
pp. 673-683 ◽  
Author(s):  
L. Cantalamessa ◽  
E. Reschini ◽  
A. Catania ◽  
G. Giustina
Keyword(s):  
Clinical Signs ◽  
Pituitary Function ◽  
Pituitary Hormone ◽  
Repeated Testing ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Prolactin Response ◽  
Plasma Gh ◽  
Lh Rh ◽  
Pituitary Irradiation

ABSTRACT The pituitary reserve of GH, prolactin, TSH, LH, and FSH has been studied in a group of 13 acromegalic patients with the aim of evaluating the pituitary function and the activity of the disease. Plasma GH, TSH and prolactin were determined after thyrotrophin releasing hormone (TRH) administration, plasma gonadotrophins and GH after luteinizing hormone releasing hormone (LH-RH) administration. The plasma TSH response to TRH was generally blunted in the patients treated with pituitary irradiation; however, none of the patients with diminished TSH reserve had signs of hypothyroidism. Six acromegalics showed prolactin basal levels higher than controls; none had galactorrhoea; 4 of them complained of impairment of the gonadal function. The prolactin response to TRH was variable and not related to prolactin basal levels. A subnormal LH reserve after LH-RH stimulation was observed in 5 out of 10 patients; 4 of them had also clinical signs of hypogonadism. A normal FSH response to LH-RH was present in all patients. A non-specific GH response to TRH and/or LH-RH was obtained in about half of the acromegalics studied. The GH responsiveness to TRH and/or LH-RH was not related to the activity of the disease or to a specific derangement of the hypothalamo-pituitary function. A concordant response was observed only between GH and prolactin response to TRH; the highest prolactin responses to TRH were obtained in the GH responsive patients. Each patient showed a constant GH pattern of response on repeated testing. Even after pituitary irradiation the pattern of GH response was unchanged in spite of lowered GH plasma levels.

GROWTH HORMONE RELEASE FOLLOWING THYROTROPHIN-RELEASING HORMONE INJECTION INTO PATIENTS WITH ANOREXIA NERVOSA

1976 ◽  
Vol 81 (1) ◽  
pp. 1-8 ◽  
Author(s):  
K. Maeda ◽  
Y. Kato ◽  
N. Yamaguchi ◽  
K. Chihara ◽  
S. Ohgo ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Anorexia Nervosa ◽  
Luteinizing Hormone ◽  
Intravenous Injection ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Basal Plasma ◽  
Plasma Gh ◽  
Lh Rh ◽  
Plasma Prl

ABSTRACT The effect of thyrotrophin-releasing hormone (TRH) or luteinizing hormone-releasing hormone (LH-RH) on plasma levels of growth hormone (GH), prolactin (PRL), thyrotrophin (TSH), and luteinizing hormone (LH), were studied in patients with anorexia nervosa. The basal plasma GH levels were elevated in 6 of 11 patients studied. Intravenous injection of synthetic TRH (500 μg) significantly raised the plasma GH levels in 9 of 11 patients. The peak values of plasma GH after TRH ranged from 6.0 to 31.5 ng/ml. Plasma GH concentrations also increased following the administration of synthetic LH-RH (100μg) in 1 of 7 patients. The intravenous injection of saline solution caused no significant change in plasma GH in these patients. The plasma LH responses to LH-RH were significantly blunted in all patients, whereas the plasma PRL and TSH responses to TRH were almost normal in the patients examined. These results suggest that the hypothalamo-pituitary function regulating GH and LH secretion is altered in patients with anorexia nervosa.

Pro-oestrous-specific role for polyamines in mediating the secretion of prolactin induced by thyrotrophin-releasing hormone in the rat

1993 ◽  
Vol 137 (1) ◽  
pp. 133-139 ◽  
Author(s):  
G. A. Wynne-Jones ◽  
A. M. Gurney
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Prolactin Secretion ◽  
Anterior Pituitary Gland ◽  
Oestrous Cycle ◽  
Male Rats ◽  
Pituitary Cells ◽  
Plasma Prolactin ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone

ABSTRACT The activity of ornithine decarboxylase (ODC) in the rat anterior pituitary gland varies during the oestrous cycle, with a rise in activity seen at pro-oestrus. This enzyme, which is rate-limiting for the synthesis of the polyamines, can be specifically and irreversibly blocked by α-difluoromethylornithine (DFMO). A previous study showed that when this drug was administered to rats in vivo on the afternoon of pro-oestrus, it suppressed the normal surge in plasma prolactin levels that occurred later that day. The effect of DFMO was associated with reduced levels of putrescine in the anterior pituitary gland, suggesting that ODC activity in the lactotroph might be involved in the prolactin surge. We have examined the effects of DFMO on the secretion of prolactin from anterior pituitary cells, isolated either from male rats or from females at different stages of the oestrous cycle. The drug was found to reduce prolactin secretion stimulated by thyrotrophin-releasing hormone (TRH), but only in cells isolated from pro-oestrous animals and only for 2 days after cell isolation. Basal secretion was unaffected by DFMO. The results imply that ODC is important for TRH-stimulated prolactin secretion at pro-oestrus, and it is specific for pro-oestrus. The prolactin surge could therefore be influenced by this ODC-dependent effect of TRH. The pro-oestrous-specific response to TRH may be a consequence of the increased ODC activity seen at this time. Alternatively, the increased ODC activity could be a consequence of coupling to TRH receptors, which are known to increase in number at pro-oestrus. Journal of Endocrinology (1993) 137, 133–139

THYROTROPHIN RELEASING HORMONE-INDUCED GROWTH HORMONE AND PROLACTIN RELEASE: PHYSIOLOGICAL STUDIES IN INTACT RATS AND IN HYPOPHYSECTOMIZED RATS BEARING AN ECTOPIC PITUITARY GLAND

1977 ◽  
Vol 72 (3) ◽  
pp. 301-311 ◽  
Author(s):  
A. E. PANERAI ◽  
IRIT GIL-AD ◽  
DANIELA COCCHI ◽  
V. LOCATELLI ◽  
G. L. ROSSI ◽  
...  
Keyword(s):  
Pituitary Gland ◽  
Anterior Pituitary ◽  
Time Lapse ◽  
Anterior Pituitary Gland ◽  
Plasma Prolactin ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Clear Cut ◽  
Urethane Anaesthesia ◽  
Releasing Effect

SUMMARY To determine how the sensitivity of the ectopic anterior pituitary gland to the GH-releasing effect of thyrotrophin releasing hormone (TRH) might be affected by the time lapse from transplantation, TRH (0·15 and 0·6 μg) was injected i.v. into hypophysectomized (hypox)-transplanted rats under urethane anaesthesia 1,3, 8,15, 30 and 60 days after transplantation, and plasma samples were taken 5 and 10 min later. Baseline GH values gradually decreased with time from about 16·0 ng/ml (1 day) to about 3·0 ng/ml (30 and 60 days). The TRH-induced GH release was absent 1 day after transplantation, present only with the higher TRH dose 3 and 8 days after transplantation, and clearly elicitable, also with the lower TRH dose (0·15 μg), from 15 up to 60 days. Determination of plasma prolactin concentrations showed a decline from about 85·0 ng/ml (1 day) to about 32·0 ng/ml (8 days); subsequently (15–60 days) prolactin values stabilized. Plasma prolactin levels increased 15 and 60 days after transplantation only when a dose of 0·6 μg TRH was given. In intact weight-matched rats, TRH induced a GH response only at the dose of 1·2 μg while a short-lived but clear-cut prolactin response could be obtained even with the 0·3 μg dose. The present results indicate that: (1) disconnexion between the central nervous system and the anterior pituitary gland greatly enhances GH responsiveness while blunting prolactin responsiveness to TRH; (2) the sensitivity of the anterior pituitary gland to the GH-releasing effect of TRH increases with time from transplantation; (3) TRH is a more effective prolactin-than GH-releaser on the pituitary gland in situ.

EFFECTS OF MATING AND INJECTION OF LUTEINIZING HORMONE RELEASING HORMONE ON SERUM LUTEINIZING HORMONE AND TESTOSTERONE CONCENTRATIONS IN RABBITS

1978 ◽  
Vol 76 (3) ◽  
pp. 417-425 ◽  
Author(s):  
C. A. BLAKE ◽  
PATRICIA K. BLAKE ◽  
NANCY K. THORNEYCROFT ◽  
I. H. THORNEYCROFT
Keyword(s):  
Luteinizing Hormone ◽  
Serum Testosterone ◽  
Serum Levels ◽  
Transient Increase ◽  
Marked Rise ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Serum Lh ◽  
Before And After ◽  
Lh Rh

The effects of coitus and injection of luteinizing hormone releasing hormone (LH-RH) on serum concentrations of LH, testosterone and dihydrotestosterone (17β-hydroxy-5α-androstan-3-one; DHT) were tested in male rabbits. Before experimentation, male and female rabbits were housed in individual cages in the same room. Male rabbits were then bled by cardiac puncture before and after placement with female rabbits or intravenous injection of LH-RH. Serum LH, testosterone and DHT were measured by radioimmunoassay. Sexual excitement (sniffing, chasing and mounting), with or without intromission, caused a marked rise in serum testosterone and DHT concentrations in only some of the bucks. These increases were accompanied or preceded by a small, transient increase in serum LH. In the rest of the bucks, sexual excitement with or without intromission had either no effect on serum levels of all three hormones, or only serum testosterone and DHT decreased during the collection period. Similar responses were measured in bucks which were housed in a room without does for 2–4 weeks before experimentation. Injection of 10, 30 or 100 ng or 50 μg LH-RH caused serum LH, testosterone and DHT to rise in all bucks tested, but the magnitude of the rises in serum testosterone and DHT were not related to the magnitude of the LH rise. In both mated and LH-RH-injected bucks, the rises in serum testosterone and DHT were greatest in animals with low initial testosterone and DHT values. Under the conditions of this study, the data suggest that: (1) serum testosterone and DHT rise in only some male rabbits after sexual excitement (with or without intromission), (2) the rises in serum testosterone and DHT are dependent on a small transient increase in serum LH and (3) sexual excitement is less likely to cause release of LH-RH in bucks with raised serum testosterone and DHT concentrations.

Stimulatory effect of thyrotrophin-releasing hormone (TRH) on the release of luteinizing hormone (LH) from rat anterior pituitary cells in vitro

1983 ◽  
Vol 61 (2) ◽  
pp. 186-189 ◽  
Author(s):  
Noboru Fujihara ◽  
Masataka Shiino
Keyword(s):  
Luteinizing Hormone ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Anterior Pituitary Cells ◽  
Lh Release ◽  
Lh Rh

The effect of thyrotrophin-releasing hormone (TRH, 10−7 M) on luteinizing hormone (LH) release from rat anterior pituitary cells was examined using organ and primary cell culture. The addition of TRH to the culture medium resulted in a slightly enhanced release of LH from the cultured pituitary tissues. However, the amount of LH release stimulated by TRH was not greater than that produced by luteinizing hormone – releasing hormone (LH–RH, 10−7 M). Actinomycin D (2 × 10−5 M) and cycloheximide (10−4 M) had an inhibitory effect on the action of TRH on LH release. The inability of TRH to elicit gonadotrophin release from the anterior pituitary glands in vivo may partly be due to physiological inhibition of its action by other hypothalamic factor(s).

scholarly journals Effect of continuous infusion of thyrotrophin-releasing hormone on plasma prolactin and on ovarian activity in melatonin-treated ewes

Reproduction ◽  
1996 ◽  
Vol 107 (1) ◽  
pp. 17-22 ◽  
Author(s):  
J. J. Robinson ◽  
R. P. Aitken ◽  
T. Atkinson ◽  
J. M. Wallace ◽  
A. S. McNeilly
Keyword(s):  
Continuous Infusion ◽  
Ovarian Activity ◽  
Plasma Prolactin ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone

Effects of infusion of thyrotrophin releasing hormone and dopamine either alone or in combination on plasma prolactin concentrations in the anoestrous ewe

1983 ◽  
Vol 96 (2) ◽  
pp. 353-357
Author(s):  
B. F. Fitzgerald ◽  
F. J. Cunningham
Keyword(s):  
Combined Treatment ◽  
Plasma Concentrations ◽  
Regulatory Role ◽  
Plasma Prolactin ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone

Plasma concentrations of prolactin in anoestrous ewes were respectively lowered or raised by the separate infusion of dopamine or thyrotrophin releasing hormone (TRH). Combined treatment with dopamine and TRH lowered the concentration of prolactin in plasma but the values increased markedly after the treatment was stopped and reached a level equivalent to that found in ewes treated with TRH alone. The results are interpreted as evidence that both dopamine and TRH play a regulatory role in determining the secretion of prolactin in the ewe.

A Chronobiological Study of Melatonin, Cortisol Growth Hormone and Prolactin Secretion in Cluster Headache

Cephalalgia ◽  
1984 ◽  
Vol 4 (4) ◽  
pp. 213-220 ◽  
Author(s):  
Guy Chazot ◽  
Bruno Claustrat ◽  
Jocelyne Brun ◽  
Daniel Jordan ◽  
Geneviève Sassolas ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Cluster Headache ◽  
Prolactin Secretion ◽  
Temporal Organization ◽  
Plasma Prolactin ◽  
Melatonin Rhythm ◽  
Plasma Melatonin ◽  
Sleep Recording ◽  
Plasma Gh ◽  
Headache Patients

The temporal organization of plasma melatonin. cortisol. growth hormone (GH) and prolactin secretion was examined in healthy rested controls and in patients suffering from episodic cluster headache. Eleven patients with typical cluster headache (10 men, 1 female) and 8 male controls were studied over a 24–h period: blood was collected at 2–h intervals during the day and at l-h intervals at night. Plasma melatonin. cortisol, GH and prolactin levels were determined by radioimmunoassay. Most of the cluster headache patients showed a decrease in nocturnal melatonin secretion and the melatonin rhythm was even completely abolished in one patient. Chronobiological analysis of the cluster headache patients' 24–h plasma melatonin profile showed a significant decrease in amplitude and mesor: these were 58.7 pg/ml and 34.4 pg/ml respectively in control subjects, versus 18.7 pg/ml and 17.6 pg/ml for the patients. In addition. patients showed a significant phase-advance in their melatonin rhythm For cortisol, the rhythm appeared slightly blunted in the cluster headache group and was significantly phase-advanced. The plasma prolactin profile showed no significant alteration, but for plasma GH the nocturnal peak was advanced in some patients: in the absence of sleep recording, however, no conclusion could be drawn. Results from this study suggest a neuroendocrine dysregulation in cluster headache in the endogenous clock which controls the pineal rhythmicity.

EFFECT OF SYNTHETIC LUTEINIZING HORMONE-RELEASING HORMONE (LH-RH) ON THE RELEASE OF GONADOTROPHINS IN CHILDREN AND ADOLESCENTS. VI. RELATIONS TO AGE, SEX AND PUBERTY

1974 ◽  
Vol 77 (3) ◽  
pp. 422-434 ◽  
Author(s):  
Philippe E. Gamier ◽  
Jean-Louis Chaussain ◽  
Elisabeth Binet ◽  
Ariane Schlumberger ◽  
Jean-Claude Job
Keyword(s):  
Luteinizing Hormone ◽  
Significant Variation ◽  
Blood Levels ◽  
First Year ◽  
Prepubertal Children ◽  
Luteinizing Hormone Releasing Hormone ◽  
Releasing Hormone ◽  
Before And After ◽  
Lh Rh ◽  
First Year Of Life

ABSTRACT Plasma gonadotrophins (LH and FSH) were radio-immunoassayed before and after injection of 0.1 mg/m2 of synthetic luteinizing hormone-releasing hormone (LH-RH) in infants 1 to 12 months old, prepubertal children aged more than 12 months, and pubertal subjects of both sexes. The pubertal changes of gonadotrophins include a highly significant increase of LH pituitary mobilizable reserve in both sexes, while the FSH reserve shows a significant decrease in females and no significant variation in males. From the first year of life up to childhood, the basal blood levels of FSH and LH decrease significantly in girls but do not vary in boys, while the FSH reserve decreases significantly in girls and increases significantly in boys, the LH reserve showing a non-significant decrease in both sexes. In the first year of life, girls show a very significantly higher FSH secretion and reserve than boys, while boys have a significantly higher LH reserve than girls. After the end of the first year up to the onset of puberty, the FSH reserve remains significantly higher in girls than in boys. The interpretation of these facts is discussed.

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