Mechanisms leading to hypogonadism in men with burns injuries.

A profound and persistent depression of serum testosterone concentrations was found in 19 men with burns injuries. This could not be explained by changes in sex hormone binding globulin capacity, hyperprolactinaemia, classical primary testicular failure, or a hypogonadotrophic state. Pulsatile release of luteinising hormone was found in control subjects but was absent or diminished in burnt patients with low serum testosterone concentrations. In addition, these patients showed reduced biological activity of luteinising hormone as measured by bioassay even though normal concentrations of luteinising hormone were detected by radioimmunoassay. The temporary hypogonadism after burns injury and possibly in other clinical states may be related to hypothalamic dysfunction, which leads to abnormal generation of luteinising hormone releasing hormone and non-pulsatile secretion of luteinising hormone of reduced biological activity.     

Loss of pulsatile luteinising hormone secretion in men with chronic renal failure.

In an attempt to determine the nature of hypothalamic and pituitary dysfunction in renal failure the secretory patterns of luteinising hormone were measured in men with end stage renal disease and compared with those in healthy controls and renal transplant recipients of similar age distribution. Mean luteinising hormone and oestradiol concentrations were significantly higher and the number of luteinising hormone secretory pulses was significantly lower in uraemic men compared with controls. Plasma testosterone and oestradiol concentrations were significantly lower in renal transplant recipients than normal men, but there were no significant differences in mean gonadotropin concentrations or the number of pulses of luteinising hormone between the two groups. As pulses of luteinising hormone are thought to reflect episodic gonadotropin releasing hormone from the hypothalamus these data suggest that uraemia interferes with central mechanisms controlling synchronised release of gonadotropin releasing hormone. This defect appears to be reversible after successful transplantation.     

Is changing hypothalamic activity important for control of ovulation?

The activity of the hypothalamic gonadotrophin releasing hormone pulse generator in women with regular ovulatory and anovulatory menstrual cycles was assessed to see whether changes therein are important determinants of normal and impaired ovarian function. Endogenous gonadotrophin releasing hormone secretion was inferred by measurement of the pituitary luteinising hormone response by characterisation of pulsatile luteinising hormone release over eight hours on three occasions during the course of follicular development and once during the luteal stage of the same cycles. In 13 ovulatory cycles (serum progesterone concentration greater than 25 nmol/l) confirmed by ovarian ultrasonography a pronounced variability in luteinising hormone pulse patterns among subjects was compatible with ovulation. In the luteal stage of ovulatory cycles the luteinising hormone interpeak interval (85 min, range 42-125) was significantly longer than that during the early follicular (64 min, 40-103), mid-follicular (62 min, 37-107), and late follicular (59 min, 39-80) stages of the same cycles. Thus in ovulatory cycles no increase in frequency of the gonadotrophin releasing hormone pulse generator was detected during follicular development, though this activity decreased in the luteal stage. In five late follicular stage studies in which part of the preovulatory luteinising hormone surge was captured no change in pulse frequency of luteinising hormone was detected compared with the mid-follicular stage of the same cycles or when compared with the late follicular stage of other cycles when no luteinising hormone surge was captured. Though mean luteinising hormone concentrations in luteinising hormone surge series (36 IU/l) were high, the amplitude of luteinising hormone pulses (165%) was only slightly greater than during non-surge late follicular stage studies (145%). Hence no change in hypothalamic gonadotrophin releasing hormone activity is required to generate the preovulatory discharge of luteinising hormone in man, which occurs as a result of the sensitising action of rising oestradiol concentrations on pituitary responsiveness to the same hypothalamic input signal. Luteinising hormone pulse frequency, peak amplitude, and mean serum luteinising hormone concentrations in seven anovulatory cycles (progesterone concentration less than 10 nmol/l) were not different from those at comparable stages of ovulatory cycles. These data suggest that the primary abnormality in this group of regularly menstruating anovulatory women lies in the ovary rather than in the hypothalamic control of the anterior pituitary.     

Long term effects of cyclophosphamide on testicular function.

Thirty men treated in childhood with cyclophosphamide for a mean of 280 days were assessed at a mean of 12.8 years after treatment for hormone concentrations and spermatogenesis. Four were azoospermic, nine oligospermic, and 17 normospermic. There was a significant inverse correlation of sperm density with cyclophosphamide dosage and duration of treatment. After a further mean follow up of 7.2 years three patients who were previously oligospermic and one who was azoospermic had normal sperm counts. All patients had normal sexual characteristics and libido. Serum androgen and prolactin concentrations did not differ significantly between patients and controls. Raised basal and stimulated follicle stimulating hormone concentrations were in keeping with impaired spermatogenesis. All patients had significantly raised luteinising hormone responses on stimulation with luteinising hormone releasing hormone. The results suggest compensated Leydig cell failure, and patients with this condition require long term evaluation of testicular function. Potential recovery of spermatogenesis with time requires appropriate counselling and contraceptive advice.     

The ability of prolactin to change the sensitivity of the pituitary of the lactating rat to luteinising hormone releasing hormonein vitro

The ability of prolactin to influence the responsiveness of the lactating rat pituitary to luteinising hormone releasing hormone has been examinedin vitro. The pituitary responsivenessin vivo to luteinising hormone releasing hormone decreased as a function of increase in the lactational stimulus. Prolactin inhibited the spontaneousin vitro release of luteinising hormone and follicle stimulating hormone to a small extent, from the pituitary of lactating rats with the suckling stimulus. However, it significantly inhibited the release of these two hormones from luteinising hormone releasing hormone-stimulated pituitaries. The responsiveness of pituitaries of rats deprived of their litter 24 h earlier, to luteinising hormone releasing hormone was also inhibited by prolactin, although minimal. It was concluded that prolactin could be influencing the functioning of the pituitary of the lactating rat by (a) partially suppressing the spontaneous release of gonadotropin and (b) inhibiting the responsiveness of the pituitary to luteinising hormone releasing hormone.     

Primary amenorrhoea: the ambiguous non-entity.

Hypothalamic-pituitary activity was investigated in 20 women with primary amenorrhoea, in whom gonadal dysgenesis and lower Müllerian duct anomalies had been excluded. There was no specific or uniform pattern of response to luteinising hormone-releasing hormone and no evidence of a common defect at pituitary-hypothalamic level to account for the absence of spontaneous menstruation. Six women had hyperprolactinaemia; of these five had radiological evidence of pituitary enlargement. The conventional distinction between "primary" and "secondary" amenorrhoea should be abandoned, and, in common with current practice for other endocrine glands, primary amenorrhoea should indicate an abnormality of the gonad itself and secondary amenorrhoea an abnormality that results from hypothalamic-pituitary dysfunction.     

Changes in pituitary hormone levels induced by met-enkephalin in man—The role of dopamine

The interaction of dopamine with the effects of the opiate agonist peptide D-Ala²-MePhe⁴-met-enkephalin-O-o1 (DAMME) on anterior pituitary hormone secretion was investigated in normal male subjects. DAMME produced clear elevations in prolactin, growth hormone and thyroid-stimulating hormone, while inhibiting the release of luteinising hormone and cortisol. There was no change in follicle stimulating hormone. The elevations in prolactin and TSH were enhanced by the dopamine antagonist, domperidone, and blocked by an infusion of dopamine. Neither dopamine nor domperidone modulated the changes in growth hormone, luteinising hormone or cortisol. The data are comptible with the association of the release of prolactin and TSH by opiate peptides with decreased hypothalamic dopaminergic activity; changes in the other anterior pituitary hormones seem to involve different mechanisms.     

Does suppressing luteinising hormone secretion reduce the miscarriage rate? Results of a randomised controlled trial.

OBJECTIVE--To determine whether prepregnancy pituitary suppression of luteinising hormone secretion with a luteinising hormone releasing hormone analogue improves the outcome of pregnancy in ovulatory women with a history of recurrent miscarriage, polycystic ovaries, and hypersecretion of luteinising hormone. DESIGN--Randomised controlled trial. SETTING--Specialist recurrent miscarriage clinic. SUBJECTS--106 women with a history of three or more consecutive first trimester miscarriages, polycystic ovaries, and hypersecretion of luteinising hormone. INTERVENTIONS--Women were randomised before conception to receive pituitary suppression with a luteinising hormone releasing hormone analogue followed by low dose ovulation induction and luteal phase progesterone (group 1) or were allowed to ovulate spontaneously and then given luteal phase progesterone alone or luteal phase placebo alone (group 2). No drugs were prescribed in pregnancy. MAIN OUTCOME MEASURES--Conception and live birth rates over six cycles. RESULTS--Conception rates in the pituitary suppression and luteal phase support groups were 80% (40/50 women) and 82% (46/56) respectively (NS). Live birth rates were 65% (26/40) and 76% (35/46) respectively (NS). In the luteal phase support group there was no difference in the outcome of pregnancy between women given progesterone and those given placebo pessaries. Live birth rates from an intention to treat analysis were 52% (26/50 pregnancies) in the group given pituitary suppression and 63% (35/56) in the controls (NS). CONCLUSIONS--Prepregnancy suppression of high luteinising hormone concentrations in ovulatory women with recurrent miscarriage and hypersecretion of luteinising hormone does not improve the outcome of pregnancy. The outcome of pregnancy without pituitary suppression is excellent.     

Cardiac abnormalities in liver cirrhosis.

Cirrhosis is associated with several circulatory abnormalities. A hyperkinetic circulation characterized by increased cardiac output and decreased arterial pressure and peripheral resistance is typical. Despite this hyperkinetic circulation, some patients with alcoholic cirrhosis have subclinical cardiomyopathy with evidence of abnormal ventricular function unmasked by physiologic or pharmacologic stress. Florid congestive alcoholic cardiomyopathy develops in a small percentage, but the concurrent presence of cirrhosis seems to retard the occurrence of overt heart failure. Even nonalcoholic cirrhosis may be associated with latent cardiomyopathy, although overt heart failure is not observed. Tense ascites is associated with some cardiac compromise, and removing or mobilizing ascitic fluid by paracentesis or peritoneovenous shunting results in short-term increases in cardiac output. Cirrhosis also appears to be associated with a decreased risk of major coronary atherosclerosis and an increased risk of bacterial endocarditis. Small hemodynamically insignificant pericardial effusions may be seen in ascitic patients. The release of atrial natriuretic peptide appears to be unimpaired in cirrhosis, although the kidney may be hyporesponsive to its natriuretic effects.     

Gonadal function in young adults after surgical treatment of cryptorchidism.

In a follow-up study of 48 young men who had been surgically treated for cryptorchidism before puberty testicular function was assessed by examining the genitalia, testicular volume, secondary sex characteristics, semen, plasma luteinising hormone (LH) and follicle-stimulating hormone (FSH) concentrations after luteinising hormone-releasing hormone stimulation, and plasma testosterone concentrations. Clinical androgen effects were normal. The mean testicular volume of both testes was in the low normal range in those who had had unilateral cryptorchidism and below normal in those who had had bilateral cryptorchidism. Of 37 patients whose sperm counts were recorded (14 bilateral) six showed azoospermia (all bilateral), five had severe oligospermia (four bilateral), and 10 had moderate oligospermia (one bilateral). In nearly all those who had had bilateral cryptorchidism and most of those who had had unilateral cryptorchidism plasma gonadotrophin levels were increased. Four cases of possible partial LH deficiency were identified. Plasma testosterone concentrations were normal in all except two patients.     

Selective increase in plasma luteinising hormone concentrations in drug free young men with mania.

The hypothalamic-pituitary-gonadal system was investigated in drug free young men with either mania or acute schizophrenia and in age matched controls by measuring, at frequent intervals during a 17 hour "neuroendocrine day," plasma concentrations of luteinising hormone (LH), follicle stimulating hormone, prolactin, testosterone, sex hormone binding globulin (SHBG), and cortisol. Plasma LH in mania was significantly increased compared with the control value at all time periods and increased in the morning and evening samples compared with values in the schizophrenic patients. Plasma prolactin and cortisol concentrations were significantly greater in mania and schizophrenia compared with control values at several times during the day, but there were no significant between group differences in plasma testosterone or SHBG. These results show that in young men with mania there is a major disturbance in the central mechanisms that control the release of LH, the control of prolactin and cortisol secretion is abnormal in mania and acute schizophrenia, and plasma LH concentrations may provide a useful hormonal diagnostic test for mania.     

Pituitary-testicular interrelationships in mumps orchitis and other viral infections

Leydig-cell function was assessed in 27 men with acute mumps orchitis by measuring plasma testosterone concentrations before and after the administration of human chorionic gonadotrophin (HCG). The test was also performed on groups of patients with other febrile viral infections and mumps without orchitis and on healthy euspermic men. The concentrations both before and after HCG were significantly lower in patients in the acute phase of mumps—but not in those with other viral infections and mumps without orchitis—than in the healthy men. Basal concentrations of follicle-stimulating hormone (FSH) and luteinising hormone (LH) were significantly increased in patients with acute mumps orchitis, while an exaggerated response to LH-releasing hormone was noted in four patients after the acute phase of the disease. Raised plasma LH concentrations were also found in several patients with viral infections, including mumps without orchitis. There appeared to be no particular merit of any of the treatments used (aspirin, prednisolone, and cold baths). In patients reevaluated three to five and 10 to 12 months after the acute phase of their disease the basal testosterone concentrations were similar to those of the healthy men, but several of the patients showed a severely impaired response to HCG. Mean basal FSH and LH concentrations were significantly increased 10 to 12 months after the acute phase, while the mean LH concentration was also raised at three to five months.It is concluded that mumps orchitis impairs Leydigcell function during the acute phase of the disease but may also have a more permanent damaging effect, similar to that found in the germinal epithelium.     

Direct effects of triiodothyronine on production of anterior pituitary hormones and gonadal steroids in goldfish

The present study investigated the effects of triiodothyronine (T3) on pituitary gonadotropin (GTH) subunits, thyroid stimulating hormone (TSH) β subunit, and growth hormone (GH) mRNA levels, as well as gonadal steroid secretion during different stages of reproduction in goldfish. Goldfish pituitary cells cultured with T3 exhibited lower tshβ mRNA levels in all reproductive stages and lower luteinising hormone β (lhβ) mRNA levels in early recrudescence, whereas gh and fshβ mRNA levels were not altered. T3 injections significantly reduced circulating oestrogen (OE2) concentrations in early and mid recrudescent male goldfish, but were without effect on the circulating level of OE2 in female fish. T3 injections also reduced circulating levels of testosterone in both male and female goldfish during the mid stage of gonadal recrudescence. In vitro culture of goldfish ovarian follicles at the late stage of gonadal recrudescence, in the presence of T3, resulted in reduced OE2 secretion; no consistent effect of T3 on testosterone secretion was observed in cultured goldfish ovarian follicles and testis. These findings support the hypothesis that T3 impairs reproduction by inhibiting production of gonadal steroids and pituitary luteinising hormone production in goldfish. Mol. Reprod. Dev. 79: 592–602, 2012. © 2012 Wiley Periodicals, Inc.     

Long term treatment with luteinising hormone releasing hormone agonists and maintenance of serum testosterone to castration concentrations.

Serum concentrations of luteinising hormone and testosterone were measured by radioimmunoassay one, two, four, seven, and 24 hours after the subcutaneous administration of 500 micrograms of the luteinising hormone releasing hormone agonist [D-Trp6, des-Gly-NH2(10)] LHRH ethylamide or [D-Ser(TBU)6, des-Gly-NH2(10)]LHRH ethylamide in patients who had previously received daily treatment with these peptides for 0, 1, 6, 12, 18, and 24 months. No increase in the serum concentrations of luteinising hormone or testosterone were detected at any time between one and 24 months'' treatment. The data show that daily subcutaneous administration of the two luteinising hormone releasing hormone agonists used at the appropriate dose can maintain concentrations of serum androgens equivalent to those after castration during long term treatment.     

One hundred pregnancies after treatment with pulsatile luteinising hormone releasing hormone to induce ovulation.

OBJECTIVE--To review treatment with pulsatile luteinising hormone releasing hormone in infertile women who do not ovulate and are resistant to clomiphene after 100 pregnancies achieved with this treatment. DESIGN--Retrospective analysis of 146 courses of treatment over 434 cycles. SETTING--Infertility clinic. PATIENTS--118 Women whose failure to ovulate was due to idiopathic hypogonadotrophic hypogonadism (n = 39), amenorrhoea related to low weight (n = 17), organic pituitary disease (n = 15), or polycystic ovaries (n = 47). INTERVENTIONS--Dose of 15 micrograms luteinising hormone releasing hormone/pulse subcutaneously every 90 minutes given with a miniaturised pump throughout cycle monitored by ultrasound. Women with hypogonadotrophic hypogonadism had 48 courses, women with amenorrhoea related to low weight 23, women with organic pituitary disease 18, and women with polycystic ovaries 57. END POINT--Follow up of 100 pregnancies achieved in 77 women during six years after introducing treatment. MEASUREMENTS and main results--One hundred pregnancies (seven multiple, 28 miscarriages). Cumulative rates of pregnancy were 93-100% at six months in women with idiopathic hypogonadotrophic hypogonadism, amenorrhoea related to low weight, and organic pituitary disease. In women with polycystic ovaries (cumulative rate of pregnancy 74%) adverse prognostic factors were obesity, hyperandrogenism, and high luteinising hormone concentrations, which were also associated with a high rate of early pregnancy loss. CONCLUSIONS--Treatment with pulsatile luteinising hormone releasing hormone is safe, simple, and effective, and the preferred method of inducing ovulation in appropriately selected patients. Compared with exogenous gonadotrophin treatment there is little need for monitoring, no danger of hyperstimulation, and a low rate of multiple pregnancies.     

The effects of nerve growth factor and anti-nerve growth factor antibody on the neuroendocrine reproductive system in the European starling Sturnus vulgaris

Thyroidectomy of starlings causes them to remain in breeding condition indefinitely; deactivation of gonadotrophin-releasing hormone neurons that is characteristic of photorefractoriness does not occur. We hypothesise that a neurotrophin, whose presence or ability to function is dependent upon thyroid hormones, is somehow involved in this termination of gonadotrophin-releasing hormone release. Nerve growth factor is one such candidate. Mouse 7S-nerve growth factor dissolved in artificial cerebro-spinal fluid was therefore infused into the lateral ventricle of thyroidectomised male starlings held on long days four times daily for 21 days and 31 days, in separate experiments, to see if photorefractoriness would occur. The result was significant gonadal regression in the treatment groups during the infusion period, with no change in testicular volume in the control groups. Testicular recrudescence occurred after the end of the treatment period. To see if this was a non-specific effect, or progression towards photorefractoriness per se, we used castrated, photorefractory starlings held on long days. Anti-nerve growth factor antibody was infused into the lateral ventricle at increasing concentrations and frequency. There was a significant rise in circulating luteinising hormone levels in the treatment groups as compared to controls, increasing with antibody dosage. Accepted: 30 January 1997     

Pituitary responsiveness to gonadotrophin-releasing and thyrotrophin-releasing hormones in children receiving phenobarbitone.

The effect of long-term treatment with phenobarbitone on pituitary responsiveness to gonadotrophin-releasing hormone and thyrotrophin-releasing hormone was studied in 20 boys being treated with the drug to prevent febrile convulsions. Baseline concentrations of luteinising and follicle-stimulating hormones were reduced as well as the responses of these hormones to stimulation with gonadotrophin-releasing hormone. Baseline prolactin concentrations were raised in comparison with those in normal children. The response of prolactin to thyrotrophin-releasing hormone, however, was impaired only in the children who had been receiving the drug for a long time. Phenobarbitone had no effect on the secretion of growth hormone. Further studies should be carried out to ascertain how long these effects on pituitary function last after phenobarbitone is withdrawn and whether this interference with pituitary function modifies the child''s subsequent development.     

Influence of serum luteinising hormone concentrations on ovulation,conception, and early pregnancy loss in polycystic ovary syndrome.

Women with the polycystic ovary syndrome do not respond well to treatment with luteinising hormone releasing hormone. To determine whether this might be due to an underlying endocrine disturbance basal concentrations of luteinising hormone were measured in 54 infertile women treated with pulsatile luteinising hormone releasing hormone and concentrations at the time of maximum follicular growth were measured in 23 of the patients. Forty one patients ovulated. Forty one patients ovulated and 27 conceived, but nine pregnancies terminated within four weeks after ovulation. Basal luteinising hormone concentrations were significantly lower in those who conceived (12.4 (range 1.3-29.0) IU/l) than in those who did not (19.0 (3.5-50.0) IU/l) and in those whose pregnancy progressed (9.6 (1.3-29.0) IU/l) than in those with early loss of pregnancy (17.9 (7.0-29.0) IU/l). Concentrations at the time of maximum follicular growth were significantly lower in women who ovulated (9.4 (2.9-35.4) IU/l) than in those who did not (29.0 (7.0-50.0) IU/l) and in those who conceived (6.2 (2.9-8.5) IU/l) than in those who did not (17.9 (4.0-50.0) IU/l). These results indicate that high concentrations of luteinising hormone during the follicular phase in women with polycystic ovaries have a deleterious effect on rates of conception and may be a causal factor in early pregnancy loss.     

Functional studies after storage at - 190 degrees C of isolated and cultivated pituitary cells from pig and rat

For the first time, it is shown here that enzymatically dispersed pituitary cells of animals survive freezing and storage at -190 degrees C in liquid nitrogen. Frozen/thawed pituitary cells from both rat and pig are able to form monolayer aggregates in culture, and to produce hormones similar to that observed with unfrozen cells. The production of both basal and LHRH (luteinising hormone releasing-hormone)-induced bioassayable LH (luteinising hormone) were measured before and after cry-opreservation. Though after cryopreservation the number of cells was reduced by about 50%, a highly significant amount of both basal and LHRH stimulation-induced release of LH was measured in cultures from frozen/thawed pituitary cells from both species.     

Plasma and Urinary Luteinizing Hormone Levels in the Diagnosis of Endocrine Disease

The diagnostic value of measurements of plasma and urinary luteinizing hormone (LH) has been studied in 209 patients with endocrine disease. In 44 patients puberty was either delayed or had failed to occur. In those with chromosomal abnormalities the LH levels were often within the normal range, whereas those with a pituitary cause usually had low levels. In boys with delayed puberty plasma LH levels rose before physical changes occurred and had prognostic value. In patients with later gonadal failure, men with impotence or infertility, and women with secondary amenorrhoea LH assays proved of little value, although in one case a premature menopause was suspected and six patients with anorexia nervosa had low LH levels.Sixty patients with disorders of the hypothalamicpituitary area were studied. Levels of LH were measured and considered in relation to the other anterior pituitary hormones. Impairment of LH secretion was one of the first effects on hormone production of disease affecting this area, and this was, of course, most readily detected in postmenopausal women.The normal ranges of both plasma and urine LH are wide and there seems to be considerable day-to-day variation, especially of urinary output. Several samples should, therefore, be measured if therapeutic decisions are involved.