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PubMed2002

Placental growth hormone and lactogen production by perifused ovine placental explants: regulation by growth hormone-releasing hormone and glucose.

The factors controlling normal placental development are poorly understood. We have previously reported the presence of ovine placental growth hormone (oPGH) and growth hormone receptors in ovine placenta, and oPGH production by the trophectoderm and syncitium during the second month of pregnancy. To identify factors regulating oPGH production, we developed a perifusion system to measure oPGH and ovine placental lactogen (oPL) production by Day 45 ovine placental explants. The mRNAs for both hormones were quantitated by real-time polymerase chain reaction in explants collected after perifusion periods of up to 8 h. Ovine PGH and oPL were released into the medium at mean rates of 2.45 +/- 0.2 and 353.6 +/- 13.6 ng/g/h, respectively. Ovine placenta produces growth hormone-releasing hormone (GHRH), but addition of GHRH to the perifusion medium did not modify either oPGH or oPL production. In vivo, oPGH production occurs between Days 30 and 60 of pregnancy. Because modulation of the maternal diet during this period affects placental development, the potential regulation of oPGH and oPL production by glucose was evaluated. Glucose supplementation of the perifusion medium resulted in a concentration-dependent decrease in oPGH release after 4 h, but oPGH mRNA levels were not affected. Production of oPL was not affected by glucose. Thus, oPGH and oPL belong to the same growth hormone/prolactin family but are differentially regulated by glucose. Ovine PGH modulations should be taken into account in metabolic experiments performed during the first trimester of pregnancy in sheep.

Animals↗
PubMed1972

Isolated pituitary gonadotrophin deficiency: gonadotrophin secretion after synthetic luteinizing hormone and follicle stimulation hormone-releasing hormone.

The responses of serum immunoreactive luteinizing hormone (LH) and follicle stimulating hormone (FSH) after intravenous injection of 100 mug of synthetic LH/FSH-RH have been studied in 14 patients with the syndrome of isolated pituitary gonadotrophin deficiency. Nine of the patients showed a rise of both hormones, two a small rise of FSH only, and three were unresponsive. In two of the unresponsive patients injection of a 500-mug dose produced a small rise of LH only. Of the patients who responded, four had LH and FSH responses within the normal adult range, while in the others the responses were smaller and delayed. It is suggested that this syndrome is due to a lack of the hypothalamic-releasing hormone itself, rather than to a pituitary deficiency. However, repeat assessment after prolonged administration of the releasing hormone will be necessary before a pituitary disorder can be excluded in all patients. The synthetic LH/FSH-RH, preferably as a depot preparation, may provide a means of treating these patients to induce the development of puberty and subsequent fertility.

Adolescent↗
PubMed1992

Effects of growth hormone-releasing hormone and somatostatin on sleep EEG and nocturnal hormone secretion in male controls.

When applied centrally to animals, growth hormone-releasing hormone (GHRH) stimulates slow-wave sleep (SWS), whereas somatostatin (SRIF) increases REM sleep. We investigated whether these peptides also affect the sleep EEG in humans when given intravenously by comparing polysomnographically the effects of four boluses of (1) placebo, (2) 50 micrograms GHRH or (3) 50 micrograms SRIF administered at 22.00, 23.00, 24.00 and 1.00 h to 7 male controls. In addition, we collected blood samples through a long catheter every 20 min from 22.00 to 7.00 h and measured plasma cortisol and growth hormone (GH) levels. In comparison with SRIF and placebo, GHRH produced a significant increase in plasma GH concentration throughout the night (mean +/- SD: 10.8 +/- 2.0 ng/ml after GHRH; 3.0 +/- 1.7 ng/ml after SRIF and 3.2 +/- 2.0 ng/ml after placebo). SRIF failed to substantially attenuate the nocturnal GH release. Nocturnal cortisol secretion was blunted after GHRH but remained unaffected by SRIF (61.4 +/- 12.9 ng/ml after placebo; 46.6 +/- 19.7 ng/ml after GHRH and 70.8 +/- 12.6 ng/ml after SRIF). Quantitative sleep EEG staging showed a significant increase in SWS after GHRH administration but no change after SRIF (percent spent in SWS per night: 14.0 +/- 5.6 after placebo, 20.2 +/- 6.6 after GHRH and 15.1 +/- 8.2 after SRIF). Application of SRIF was accompanied by a trend toward increased REM density. The effects of episodic GHRH administration upon SWS, GH and cortisol secretion were opposite to those previously reported for corticotropin-releasing hormone, which supports the view that neuroregulation of human sleep involves an interaction of central GHRH and corticotropin-releasing hormone.

Adult↗
PubMed1990

Effects of thyroid hormone deficiency and replacement on rat hypothalamic growth hormone (GH)-releasing hormone gene expression in vivo are mediated by GH.

The role of thyroid hormone and GH in the regulation of hypothalamic GH-releasing hormone (GRH) gene expression in the rat was examined after the induction of thyroid hormone deficiency by thyroidectomy. Thyroidectomy resulted in a time-dependent decrease in hypothalamic GRH content, which was significant by 2 weeks postoperatively, and a reduction in pituitary GH content to 1% of the control level by 4 weeks. In contrast, GRH secretion by incubated hypothalami under both basal and K(+)-stimulated conditions was increased after thyroidectomy. Hypothalamic GRH mRNA levels also exhibited a time-dependent increase, which was significant at 1 week and maximal by 2 weeks after thyroidectomy. Administration of antirat GH serum to thyroidectomized rats resulted in a further increase in GRH mRNA levels. T4 treatment of thyroidectomized rats for 5 days, which also partially restored pituitary GH content, lowered the elevated GRH mRNA levels. However, comparable effects on GRH mRNA levels were observed by rat GH treatment alone. These results suggest that the changes in hypothalamic GRH gene expression after thyroidectomy in the rat are due to the GH deficiency caused by thyroidectomy, rather than a direct effect of thyroid hormone on the hypothalamus, since the changes were reversible by GH alone despite persistent thyroid hormone deficiency. In addition, they further support the role of GH as a physiological negative feedback regulator of GRH gene expression.

Animals↗
PubMed2002

Responses of bone turnover markers and bone mineral density to growth hormone therapy in children with isolated growth hormone deficiency and multiple pituitary hormone deficiencies.

Growth hormone deficiency (GHD) is an important cause of decreased bone mass in childhood and adolescence. The role of other pituitary hormone deficiencies on bone mass is still a query in children. Thirty-nine children (28 with isolated GHD [IGHD] and 11 with multiple pituitary hormone deficiency [MPHD]) were investigated to show the effects of IGHD vs MPHD on bone status. Bone turnover markers (calcium, phosphate, alkaline phosphatase [ALP] Bone ALP [BALP], osteocalcin [OSC], carboxyterminal propeptide of type-1 collagen [CPP-I], parathyroid hormone [PTH]) were measured before and every four months during growth hormone (GH) therapy; bone mineral density (BMD) of the lumbar spine was measured before and every six months during therapy. All bone turnover markers except calcium and PTH increased significantly during 1 year of GH therapy. There were no differences in the levels of bone turnover markers between children with IGHD and MPHD at baseline, and after 4, 8 and 12 months of therapy. Lumbar spine BMD SDS of all patients increased significantly during 1 year of therapy (p = 0.035 after 6 months and p <0.001 after 12 months compared with baseline). BMD SDS of both IGHD and MPHD groups were similar at baseline and after 6 and 12 months of therapy (p = 0.235, p = 0.295 and p = 0.384). Height SDS (HtSDS) at baseline was the most important predictor of baseline BMD SDS in children with GHD (t = 4.166, p <0.001). DeltaHtSDS was also positively related to deltaBMD SDS after 1 year of GH therapy. In conclusion, there was no difference in bone status of the patients with IGHD and MPHD at baseline. GH therapy yielded similar increases in bone mass in both groups. Increase in height contributed to increase in BMD during 1 year of GH therapy.

Age Determination by Skeleton↗
PubMed1996

Growth hormone response to growth hormone-releasing hormone varies with the hypothalamic-pituitary abnormalities.

We determined growth hormone (GH) and insulin-like growth factor I (IGF-I) levels after a 3 h infusion of escalating doses of growth hormone-releasing hormone (GHRH(1-29)) followed by a bolus injection in hypopituitary patients with marked differences in pituitary features at magnetic resonance imaging (MRI) in order to evaluate further the contribution of MRI in the definition of pituitary GH reserve in GH-deficient patients. Twenty-nine patients (mean age 14.5 +/- 4.0 years) were studied. Group I comprised 13 patients: seven with isolated GH deficiency (IGHD) (group Ia) and six with multiple pituitary hormone deficiency (MPHD) (group Ib) who had anterior pituitary hypoplasia, unidentified pituitary stalk and ectopic posterior pituitary at MRI, Group II consisted of eight patients with IGHD and small anterior pituitary/empty sella, while in group III eight had IGHD and normal morphology of the pituitary gland. Growth hormone and IGF-I levels were measured during saline infusion at 08.30-09.00 h, as well as after infusion of GHRH (1-29) at escalating doses for 3h: 0.2 micrograms/kg at 09.00-10.00 h, 0.4 micrograms/kg at 10.00-11.00 h, 0.6 micrograms/kg at 11.00-12.00 h and an intravenous bolus of 2 micrograms/ kg at 12.00 h. In the group I patients, the peak GH response to GHRH(1-29) was delayed (135-180 min) and extremely low (median 2mU/l). In group II it was delayed (135-180 min), high (median 34.8 mU/l) and persistent (median 37.4 mU/l at 185-210 min). In group III the peak response was high (median 30.8 mU/l) and relatively early (75-120 min) but it declined rapidly (median 14.4 mU/l at 185-210 min). In one group I patient, GH response increased to 34.6 mU/l. The mean basal value of IGF-I levels was significantly lower in group I (0.23 +/- 0.05 U/ml) than in groups II (0.39 +/- 0.13U/ ml, p < 0.01) and III (1.54 +/- 0.46 U/ml, p < 0.001) and did not vary significantly during the GHRH(1-29) infusion. The present study demonstrates that the impaired GH response to 3 h of continuous infusion of escalating doses of GHRH(1-29) was strikingly indicative for pituitary stalk abnormality, strengthening the case for use of GHRH in the differential diagnosis of GH deficiency. The low GH response, more severe in MPHD patients, might be dependent on the residual somatotrope cells, while the better response (34.6 mU/l) in the group Ia patients might suggest that prolonged GHRH infusion could help in evaluating the amount of residual GH pituitary tissue. Pituitary GH reserve, given the GH response to GHRH infusion in GH-deficient patients with small anterior pituitary/empty sella, seems to be maintained.

Diagnosis, Differential↗
PubMed1996

Contrasts in the gonadotropin-releasing hormone dose-response relationships for luteinizing hormone, follicle-stimulating hormone and alpha-subunit release in young versus older men: appraisal with high-specificity immunoradiometric assay and deconvolution analysis.

The secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) is regulated by gonadotropin-releasing hormone (GnRH). As men age, mean serum concentrations of immunoreactive gonadotropic hormones tend to increase, while serum testosterone concentrations tend to decline. To evaluate age-related changes in gonadotroph cell function, we have assessed the dose-dependent secretory responses of immunoreactive LH, FSH and alpha-subunit to saline versus five doses of GnRH in older and young men. Ten older men, mean age 66 years (range 61-78), and nine young men, mean age 26 years (range 22-30), received iv bolus injections of GnRH (range 10-100 micrograms) in randomized order every 2 h, except that the 100-microgram dose was always given last. Blood samples for immunoradiometric assays of serum LH, FSH and alpha-subunit concentrations were obtained every 10 min for a total of 12 h, which included a 2-h preinjection baseline. Deconvolution analysis was performed to estimate gonadotropin and alpha-subunit secretory burst mass, amplitude and duration, as well as endogenous LH, FSH and alpha-subunit half-lives. The mean (+/- SEM) baseline 2-h serum FSH (IU/I) concentration was higher in older than younger men (5.9 +/- 0.8 vs 3.8 +/- 0.5, p < 0.05). The mean 2-h serum LH concentrations after GnRH were significantly higher than corresponding values in young men at GnRH doses of 25, 50 and 75 micrograms, and in the case of FSH at GnRH doses of 10 and 25 micrograms. Non-linear curve-fitting of these dose-response relationships revealed that the calculated maximal mean 2-h serum LH concentration response (IU/l) was higher in older than young men following GnRH stimulation: 15.4 (13.5-16.2) vs 10.8 (8.7-12.1) (95% confidence interval). The maximal mean 2-h serum FSH concentration response (IU/l) was also significantly higher in older men: 11.9 (10.2-13.1) versus 8.6 (7.2-9.6). Maximal alpha-subunit responses (microgram/l) were similarly increased in the older cohort: 1.16 (0.99-1.25) vs 0.83 (0.71-0.91). The incremental LH (p < 0.05) and FSH (p < 0.01) secretory burst mass from 10 to 25 micrograms GnRH was significantly greater in older than younger men. The LH and FSH half-lives and second component alpha-subunit half-lives were similar in older and young men. In addition, secretory burst durations were invariant of age. In contrast, by non-linear curve-fitting, the calculated mass of LH secreted was higher in older men at 13.5 (11.8-15) vs 10.6 (9.2-11.7) IU/l of distribution volume (p < 0.05) for the maximal absolute mass and 11.3 (9.5-12.7) vs 7.4 (6.0-8.4) IU/l (p < 0.05) for the maximal incremental mass of LH secreted after GnRH. The estimated maximal mass of FSH secreted after GnRH also was higher in older men: 4.6 (3.4-5.5) vs 3.2 (2.9-3.4) IU/l (p < 0.01). Finally, calculated maximal GnRH-stimulated alpha-subunit secretory burst mass was statistically greater in older individuals: 2.3 (1.8-2.5) vs 1.6 (1.4-1.8) micrograms/l. In contrast, half-maximally effective GnRH doses were not different in the two age groups. We conclude that older men show significantly increased maximal and incremental gonadotropin release due to amplified secretory burst mass in response to escalating doses of GnRH with no evident differences in LH, FSH, or alpha-subunit half-lives or secretory burst durations. Increased gonadotroph responsiveness may be due to diminished gonadal hormone negative feedback or primary alterations in the hypothalamo-pituitary unit with aging.

Adult↗
PubMedDate not supplied

[Immunochemical method of determining the biosynthesis of hypophyseal hormones. Effect of liberins and cyclic AMP on the biosynthesis of luteinizing hormone, prolactin and growth hormone in the rat pituitary].

A simple procedure is developed, which enables to estimate sequentially the biosynthesis of luteinizing hormone (LH), prolactin (LTH) and somatotropic hormone (STH) in rat hypophysis using solid-phase immunosorbents prepared on the basis of antisera to the hormones studied, copolymerized with chlorcarbonic acid isobutyl ester. The immunosorbents exhibited high specificity and pronounced immunosorption capacity. The analysis was carried out as follows: incubation of hypophyses with 14C-lysine in vitro, chromatography of the hypophysis extracts on columns with Sephadex G-25 and immunosorption of hormones. Within 4 hrs of incubation the biosynthetic processes in hypophysis were distinctly increased, reaching maximal values between 4 hrs and 6 hrs of incubation. Biosynthesis of LH and LTH in adult females exceeded 2-fold the STH biosynthesis and in 23 days old female rats the STH biosynthesis was more than 1.5- and 3-times higher than that LH and LTH synthesis. Luliberin at a dose 1.5 X 10(-6) M/hypophysis stimulated biosynthesis of LH, inhibited LTH biosynthesis but did not affect the STH synthesis in vitro. Thyroliberin (3.0 X 10(-6) M/hypophysis) stimulated LTH and STH biosynthesis and did not affect the LH synthesis. Dibutyryl-cAMP (0.5 X 10(-3) M/hypophysis) stimulated biosynthesis of all these hormones.

Animals↗
PubMed1977

The influence of glycyl residues on the flexibility of peptide hormones in solution. A 13C-nuclear-magnetic-resonance study of luteinizing hormone-releasing hormone (luliberin) and its des-glycinamide10 N-ethylamide analog.

13C nuclear magnetic resonance spectroscopy in used to gain information on the flexibility of the backbone in peptide hormones and peptide hormone analogs. 13C spin-lattice relaxation times (T1) were measured on luliberin, the luteinizing-hormone-releasing hormone and des(Gly-NH2)10-luliberin-N-ethylamide in aqueous solution at 25.2 and 67.9 MHz at temperatures of 32 degrees, 40 degrees and 55 degrees C. The 13C spin-lattice relaxation times indicate increased flexibility of the peptide backbone in the immediate environment of glycyl residues in luliberin (less than Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH2) and the hormone analog des(Gly-NH2)10-luliberin-N-ethylamide (less than Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-NH-CH2CH3) in aqueous solutions. 13 C NMR spectroscopy is shown to be a sensitive technique for monitoring the time-averaged conformational flexibility of peptides in solution. Activation energies (Ea) of about 25 kJ/mol were obtained for rotational reorientation of non-terminal alpha-carbons in the peptide backbone. Rotation of methyl groups was characterized by an Ea of 9.6 kJ/mol whereas reorientation of the N-terminal pyroglutamyl residue showed an Ea value of 14.6 kJ/mol. The Ea values of individual carbons in the side-chains of prolyl, arginyl and leucyl residues in the peptides were similar to those obtained for the alpha-carbon of the same amino acid residue in the peptide backbone of the hormones.

Calorimetry↗
PubMed1987

Effect of a low-fat diet on hormone levels in women with cystic breast disease. II. Serum radioimmunoassayable prolactin and growth hormone and bioactive lactogenic hormones.

For investigation of the bioactivity of circulating prolactin and growth hormone (lactogenic hormones) in symptomatic benign breast disease, serum was assayed by the Nb2 lymphoma cell method in premenopausal patients with cystic breast disease and cyclic mastalgia and in normal premenopausal women. The results were compared with serum prolactin and growth hormone concentrations determined by radioimmunoassay. The serum bioassayable hormone levels in the benign breast disease patients (74.0 +/- 77.6 ng/ml) were significantly higher (P less than .001) than in normal women (23.8 +/- 10.7 ng/ml). There were no significant differences in the radioimmunoassayable prolactin or growth hormone levels between the 2 groups. When 16 cystic breast disease patients were placed on a low-fat (20% of total kilocalories) diet for 3 months, there were significant reductions in the serum bioassayable hormone levels (P less than .02). It is concluded that the bioactivity of prolactin may be elevated in the serum of patients with cystic breast disease and cyclic mastalgia, without corresponding increases in levels determined by radioimmunoassay; that this abnormality is reversible by a reduction in dietary fat consumption to 20% of the total kilocalories; and that serum prolactin may provide a valuable biomarker in clinical trials of a low-fat diet in women at high breast cancer risk.

Adult↗
PubMed1993

Human growth hormone and growth hormone releasing hormone: a double-masked, placebo-controlled study of their effects on bone metabolism in elderly women.

We treated 42 postmenopausal women with decreased bone mass for 12 weeks with human growth hormone, growth hormone releasing hormone, or placebo. Bone density and biochemical markers were determined before and during treatment, and 4 weeks after withdrawal. Biochemical markers of bone formation and resorption increased significantly in the group treated with growth hormone, whereas no changes were seen in the other groups. After withdrawal of therapy the bone markers declined without reaching baseline values. Bone density in the forearm, spine and proximal femur was unchanged in all groups. We conclude that treatment with growth hormone stimulates bone metabolism in elderly postmenopausal women with decreased bone mass.

Absorptiometry, Photon↗
PubMed1988

Response to a growth hormone-releasing hormone analog in heifers treated with recombinant growth hormone.

Sixteen pregnant Holstein heifers (430kg) were used to determine the effect of long-term administration of a bovine growth hormone (bGH) made by recombinant DNA technology on the ability of a bolus injection of a growth hormone-releasing hormone analog (Ac-His-1, D-Ala-2, Nle-27, GHRH(1-29 NH2) to increase serum GH. Eight heifers received a daily intramuscular injection of bGH (50 mg/day) for 5 months while the other half received a daily injection of physiological saline (control) over the same period. On the last day of bGH treatment and 1, 5, 10 and 25 days after the cessation of bGH treatment, five heifers from each group were challenged with GHRH analog and the response to this releasing hormone analog was measured. Basal GH concentrations were elevated on the last day of treatment in bGH-treated heifers and declined to concentrations similar to control heifers by 1 day after cessation of treatment. Response to GHRH analog was impaired by bGH during the last day of treatment and one day later. Responsiveness returned to a level similar to controls by 5 days after the end of bGH treatment. Response to GHRH analog was lessened during the period of bGH treatment but there were no long term effects on the animals' ability to respond to the releasing hormone.

Animals↗
PubMed1989

Effects of two years of methionyl growth hormone therapy in two dosage regimens in prepubertal children with short stature, subnormal growth rate, and normal growth hormone response to secretagogues. (Dutch Growth Hormone Working Group).

Thirty short, slowly growing children with normal plasma growth hormone response to standard provocation tests were randomly assigned to a group (n = 20) undergoing therapy with methionyl growth hormone, 2 IU/m2 subcutaneously once daily, (group 1) or a control group (n = 10, group 2). The mean (+/- SD) height velocity increment in group 1 was 3.0 +/- 1.9 cm/yr in the first year, compared with -0.2 +/- 0.7 cm/yr in group 2. Of the 18 children who completed the first year of treatment, 12 had a height velocity increment of more than 2 cm/yr and 11 of them continued treatment for a second year (group 1A). The remaining six children also reached height velocities greater than the mean for bone age, but because of a low height velocity increment they were termed nonresponders and their growth hormone dosage was increased to 4 IU/m2/day (group 1B). Of the 10 children in the control group, seven received authentic biosynthetic growth hormone in the second year of the study (group 2); the remaining three received no therapy (group 3). The mean height velocities (measured in centimeters per year) before and during the first and second years of therapy were 3.6, 7.6, and 6.1 in group 1A; 5.7, 6.9, and 7.3 in group 1B; 4.2, 4.0, and 6.7 in group 2; and 5.0, 4.9, and 5.2 in group 3. The effect of doubling the dosage was a further increase of 1.9 cm/yr. Bone age advance paralleled growth acceleration, resulting in an unchanged height standard deviation score for bone age and ambiguous results on final height prediction. Growth hormone therapy in such short children appears to be safe and efficacious in increasing growth velocity for 2 years, but its efficacy in terms of increasing final height is uncertain.

Age Determination by Skeleton↗
PubMed1999

Prospective determination of the hormonal response after cessation of luteinizing hormone-releasing hormone agonist treatment in patients with prostate cancer.

OBJECTIVES: To determine the hormonal (luteinizing hormone [LH] and testosterone) and biochemical (serum prostate-specific antigen [PSA]) response to withdrawal of luteinizing hormone-releasing hormone (LHRH) agonists in patients who received more than 2 years of LHRH therapy for advanced prostate cancer. METHODS: Fourteen patients with clinical Stage T3 or higher prostate cancer and no evidence of clinical or biochemical progression, who had received 2 years or more of LHRH therapy, were enrolled at the time of their scheduled 3-month depot injection. Patients underwent history, physical examination, and measurement of serum PSA, LH, and testosterone at baseline, monthly for 3 months, and then every 3 months for 1 year following LHRH withdrawal. RESULTS: The mean age of patients was 70.3 years (range 56 to 84). Patients previously received LHRH agonist for a mean of 38.6 months (range 25 to 82). All patients had castrate levels of testosterone (median 10.0 ng/dL) and suppressed LH levels (median 0.1 mIU/mL) at baseline. Median baseline PSA was 0.15 ng/mL. On multiple groupwise comparison, there was no significant change (compared with baseline) in LH or testosterone until 6 months after withdrawal and no change in PSA throughout the duration of the study (median PSA at 1 2 months 0.30 ng/mL). Despite significant increases in LH and testosterone when compared with baseline beginning at 6 months, both LH and testosterone remained markedly suppressed, with median testosterone remaining in the castrate range at both 6 and 9 months and significantly below the lower limit of normal at 12 months (median 111.0 ng/dL). Despite no statistically significant change for the entire cohort in serum PSA, a rising PSA was noted in 4 patients between 3 and 9 months, and LHRH therapy was reinitiated. The remaining patients continued to have suppressed LH and testosterone, with 4 patients remaining in the castrate range at 12 months. CONCLUSIONS: The recovery of function of the hypothalamic-pituitary-testicular axis after prolonged LHRH administration is variable. Castrate levels of testosterone and suppressed LH may persist even up to 1 year after discontinuing LHRH. These results have significant implications regarding the interpretation of clinical trials incorporating neoadjuvant and adjuvant hormonal therapy. Further studies are needed to expand on these preliminary observations and should also address the feasibility of incorporating LHRH withdrawal into clinical practice.

Aged↗
PubMed1999

Correlations of plasma growth hormone with somatostatin, gonadal steroid hormones and thyroid hormones in rainbow trout during sexual recrudescence.

The study explores the interrelationships among growth hormone (GH), somatostatin-14 (SRIF), non-esterified fatty acids (NEFA), gonadal steroid hormones and thyroid hormones (THs) in sexually recrudescent rainbow trout (Oncorhynchus mykiss) to examine aspects of the complex set of physiological changes associated with gonadal growth and maturation. Females exhibited significant decreases in plasma SRIF, NEFA and triiodo-L-thyronine (T3) concentrations, and a significant increase in plasma GH concentration associated with gonadal maturation, whereas in males, only SRIF and NEFA concentrations showed significant changes during testicular maturation. The declining SRIF levels during gonadal recrudescence may indicate a role for the hormone in the energy repartitioning processes that occur in both sexes at this time. Correlation analysis of plasma variables revealed a direct correlations between plasma NEFA and 17 beta-estradiol (E2) in females, an inverse correlation between NEFA and testosterone (T) in males, inverse correlations between GH and SRIF in both males and females, and inverse correlations between THs and SRIF concentrations in females. These marked gender differences in correlations likely reflect the different physiological challenges faced by the two sexes and emphasizes the need to consider gender, as well as maturity when studying the interactions of hormones.

Animals↗
PubMed2005

Serum luteinizing hormone, follicle-stimulating hormone and oestradiol pattern in women undergoing pituitary suppression with different gonadotrophin-releasing hormone analogue protocols for assisted reproduction.

Gonadotrophin-releasing hormone analogues (GnRH-a) are used widely in controlled ovarian stimulation (COS) cycles for assisted reproduction. At present, there is great debate about the influence of exogenous hormone activity on the hypothalamus-pituitary axis following pituitary desensitization. The objective of this comparative study was to investigate the pattern of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and oestradiol in women undergoing ovarian stimulation with different GnRH-a preparations. We retrospectively analysed 201 women, aged between 27 and 43 years, who were referred consecutively to our infertility clinic between January 2002 and January 2003. All women had no endocrinopathies or occult ovarian failure as assessed by day-3 hormone profile. Women were enrolled in one of the following COS protocols: depot triptorelin long protocol (n = 38), buserelin long protocol (n = 101) or buserelin short protocol (n = 62). Recombinant FSH was used to induce ovulation. Treatment was monitored by transvaginal ultrasound scan and serum measurement of FSH, LH and oestradiol. Among the women initially included, 30 had cancelled cycles due to poor ovarian response. Serum LH levels were significantly higher in the short-protocol group compared with the long-protocol groups (p < 0.001). The number of follicles, oocyte yield, number of grade-I embryos and fertilization rate were significantly lower in the short-protocol group than in the long-protocol groups. These findings showed that LH concentrations are significantly higher in women undergoing reversible medical hypophysectomy with a GnRH-a short protocol than in women treated with a long protocol. The hypothesis of an LH ceiling is confirmed.

Adult↗
PubMedDate not supplied

Long-term, pulsatile, low dose, subcutaneous luteinizing hormone-releasing hormone administration in men with idiopathic oligozoospermia. Failure of therapeutic and hormonal response.

In four normal men with a history of long standing infertility, severely disturbed sperm qualities (determined in at least three spermiograms), normal serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels (measured over a time period of 90 minutes), and lack of evidence of further andrological or other obvious endocrine disorders the effectiveness of luteinizing hormone-releasing hormone (LH-RH) treatment was investigated. LH-RH was administered subcutaneously with a portable, comterized infusion pump (Zyclomat) for 3 months, with administration intervals of 90 minutes and bolus dosages of 5 micrograms (three patients) and 20 micrograms (one patient). Semen qualities during and after LH-RH treatment, as compared to pretreatment values, showed no improvement in volume of ejaculate, number of sperms per milliliter and motility. During or at the end of the treatment period no evident differences were observed in serum LH, FSH and testosterone levels (measured over a 90 minutes period) compared with hormonal values before LH-RH therapy, nor at the low-dose (5 micrograms) neither at the high-dose (20 micrograms) administration schedule. It is concluded that pulsatile subcutaneous LH-RH treatment in normogonadotropic, oligozoospermic men does not seem to improve the therapeutical arsenal.

Adult↗
PubMed1986

Secretion of neuron-specific enolase, prolactin, growth hormone, luteinising hormone and follicle stimulating hormone by "functionless" and endocrine-active pituitary tumours in vitro.

Secretion of the neuroendocrine marker neuron-specific enolase by 24 pituitary tumours was measured in maintenance tissue culture. Eleven endocrine-active and 13 "functionless" tumours were defined by measurement of prolactin, growth hormone, luteinising hormone (LH) and follicle stimulating hormone (FSH) secretion rates in vitro and the corresponding plasma hormone levels. Measurement of prolactin secretion provided a clear distinction between true prolactinomas and "functionless" tumours causing hyperprolactinaemia by stalk compression (pseudoprolactinomas). A previous report of LH and/or FSH secretion by the majority of "functionless" tumours was confirmed, but plasma levels of LH and FSH were usually normal. It is argued that LH and FSH are not the major hormones secreted by "functionless" tumours. A high production rate of neuron-specific enolase appears to be characteristic of the cell type from which most "functionless" tumours derive.

Adenoma↗