Synchronization of augmented luteinizing hormone secretion with sleep during puberty

Neural regulation of pituitary function

Neural regulation of pituitary function can serve as a basis for understanding endocrine and reproduction dysfunction in epilepsy. Because the pituitary gland is the final common pathway for central neural modulation of the endocrine system, hypothalamic control of pituitary function is important. The syndrome of functional hypothalamic amenorrhea is an example of stress-induced alteration in endocrine function and may serve as a model to suggest the impact of limbic system activation on reproduction and the endocrine milieu.

Lateralized rhythms of the central and autonomic nervous systems

This paper reviews lateralized ultradian rhythms in the nervous system and their unique place in evolutionary development. The rhythmic lateralization of neural activity in paired internal structures and the two sides of the central and autonomic nervous system is discussed as a new view for the temporal and spatial organization of higher vertebrates. These lateralized neural rhythms are integral to the hypothesis of the basic rest-activity cycle. Rhythms of alternating cerebral hemispheric dominance are postulated to be coupled to oscillations of the ergotrophic and trophotrophic states. The nasal cycle is coupled to this cerebral rhythm. This lateralized central and autonomic rhythm is discussed in relationship to ultradian rhythms of neuroendocrine activity, REM and NREM sleep, lateralized rhythms of plasma catecholamines, and other lateralized neural events. The relationship of this phenomenon to stress and adaptation is postulated. The effects of unilateral forced nostril breathing is reviewed as a method to alter cerebral activity, cognition, and other autonomic dependent phenomena.

Pattern of secretion of bioactive and immunoreactive gonadotrophins in normal pubertal children

OBJECTIVE

The aim was to investigate the relationship between the nocturnal pulsatile secretory patterns of immunoreactive and bioactive luteinizing hormone in normal children at various stages of puberty.

DESIGN

Blood samples were taken at 15-minute intervals from 2000 hours to 0800 hours. Pubertal stage was assessed by the method of Tanner (1962).

PATIENTS

Thirty-four healthy siblings (17 males, 17 females) of diabetic children were recruited (median age 13.1, range 9.1-20.9 years). They were of normal height, non-obese, and covered the range of puberty.

MEASUREMENTS

Follicle stimulating and luteinizing hormone levels were measured by radioimmunoassay in all 34 subjects; bioactive LH (B-LH) was assayed in a subgroup of 13 subjects selected to encompass the range of normal puberty. Oestradiol (girls) and testosterone (boys) were also measured at hourly intervals.

RESULTS

Immunoreactive luteinizing and follicle stimulating hormone concentrations showed a progressive rise during puberty in both sexes. FSH concentrations were significantly higher in females than in males at all stages of puberty. Overnight mean bioactive luteinizing hormone concentrations were higher than immunoreactive luteinizing hormone levels in all the girls studied (n = 7). Although the number of bioactive luteinizing hormone pulses (31) was greater than immunoreactive pulses (27), the profiles were generally very similar. In the early pubertal girls an increase in the bioactive: immunoreactive ratio was observed during the middle of the night with the onset of pulsatility. Oestrogen was detected in the girls in breast stage 4-5 but not in two of the early pubertal girls, despite pulses of immunoreactive and bioactive luteinizing hormone. The boys had higher mean bioactive than immunoreactive luteinizing hormone levels and overall bioactive and immunoreactive luteinizing hormone and testosterone concentrations increased with puberty stage. Concordance between bioactive and immunoreactive hormone pulses was good although more immunoreactive pulses (16) were seen than bioactive pulses (14). As in the girls, an increase in the bioactive: immunoreactive ratio was observed in the middle of the night with the onset of pulsatility at genital stage 2 but, in contrast to the oestrogen data in the girls, testosterone secretion always followed luteinizing hormone pulsatility overnight.

CONCLUSION

We conclude that mean overnight immunoreactive luteinizing and follicle stimulating hormone concentrations increase during puberty in both sexes. Bioactive luteinizing hormone levels are two to three times higher than immunoreactive luteinizing hormone in both sexes, but there is very little discordance between immunoreactive and bioactive luteinizing hormone pulsatility. The bioactive: immunoreactive ratio increases with the occurrence of pulsatility overnight in early pubertal children. The relationship between these changes in bioactive and immunoreactive luteinizing hormone and sex steroids is clearest in boys where the nocturnal testosterone rise always follows pulsatile LH secretion.

Pulsatile immunoreactive and bioactive luteinizing hormone secretion in adolescents with chronic renal failure. The Cooperative Study Group on Pubertal Development in Chronic Renal Failure (CSPCRF)

Delayed or arrested pubertal development is common in children with chronic renal failure (CRF). Normal puberty is initiated by the onset of episodic nocturnal secretion of luteinizing hormone (LH) containing an increasing proportion of bioactive hormone. To test the functional integrity of the hypothalamo-pituitary axis in CRF we measured immunoreactive (i-LH) and bioactive (bio-LH) plasma LH concentrations at 15-min intervals from 2000 to 0700 hours in 65 pubertal patients aged 10-23 years [46 boys/19 girls; 20 on conservative treatment (CT), 13 on dialysis (D), 32 with transplants (TP)]. i-LH was determined by radio-immunoassay and bio-LH by a mouse Leydig cell assay. Peak detection was performed by the cluster analysis computer programme. The mean (+/- SD) number of i-LH (in both sexes) and bio-LH pulses (in boys) per profile, and the mean peak area of i-LH (in both sexes) and bio-LH (in girls) were higher in TP than in CT or D patients. The ratio of bio-LH to i-LH increased during puberty in CT (G1 vs G4/5, 0.3 +/- 0.5 vs 1.8 +/- 0.,4) and TP (0.6 +/- 0.7 vs 1.8 +/- 0.7) but remained low in male D patients (0.4 +/- 0.7 vs 1.1 +/- 0.8). The ratios were subnormal, however, even in mature TP patients compared with healthy adults. The bio-LH/i-LH ratio and the bio-LH peak area best predicted integrated nocturnal testosterone concentrations in TP but not in uraemic male patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Gonadotropin-releasing hormone agonist testing of pituitary-gonadal function

The development of gonadotropin-releasing hormone (GnRH) agonists has provided a unique means to functionally assess the pituitary-gonadal axis in both males and females. These agonists, when given in a dose sufficient to stimulate the gonadotropes and induce a gonadal steroid response, have provided insights into normal reproductive physiology, hyperandrogenic conditions such as the polycystic ovary syndrome (PCOS), and disorders of pubertal development. This review provides an overview of the use of such agonists as probes of the functional status of the pituitary-gonadal axis in both normal and abnormal reproductive states.

Neuroendocrine rhythms

Hormones are secreted with circhoral, circadian and seasonal periodicities. Circhoral pulsatility is a temporal code, many chronic and acute changes in neuroendocrine status being mediated by changes in the frequency of circhoral release. The identity of the neuronal circuits controlling circhoral release is not known. Circadian release of hormones occurs with a precise temporal order entrained to the light-dark cycle, synchronized to the activity/rest rhythm and generated by circadian oscillators, of which the suprachiasmatic nuclei are the most important. Seasonal rhythms are driven either by an endogenous circannual clock mechanism or by a process of photoperiodic time measurement which is dependent upon the duration of the nocturnal peak of the pineal hormone melatonin.

Neuroendocrine control of human reproduction in the male

The traditional difficulty in studying the neuroendocrine control of reproduction in the human male has been the inability to tease out the hypothalamic from the pituitary component of this neuroendocrine system. The use of multiple models, each with its own strength and weakness, represents an overlapping approach that has permitted further insights to be gained into the hypothalamic control of the neuroendocrine regulation of gonadotropin secretion in the human. Such an insight is an important prerequisite to the understanding of the pathophysiology of various disease states, the unraveling of a control of FSH secretion by GnRH vs other modulators, and the subsequent design of rational therapies for male reproductive disorders.

Primary and secondary testicular insufficiency

The possibility of testicular insufficiency is a common problem for the pediatric practitioner. Presentation varies with the severity of the defect, the developmental age achieved before onset, and the presence of associated other abnormalities. Most commonly, primary and secondary testicular insufficiency present at the time of puberty, but the presentation may be at birth or in the early neonatal period. Appropriate investigations may uncover the diagnosis at the time and allow intervention later at the appropriate age. Secondary testicular failure, although more difficult to diagnose and to differentiate from simple delay of development, offers the possibility of later development of spermatogenesis and the attainment of fertility through the use of gonadotropins or GnRH replacement programs. In primary testicular failure, because it implies an intrinsic abnormality of the functioning elements of the testis, spermatogenesis is not inducable by hormonal stimulation. Treatment of testicular failure in the neonatal period is unnecessary unless micropenis is associated. In the pubertal boy, testosterone replacement is the treatment of choice and should be initiated carefully, taking into consideration the age of the subject, his bone age, and the psychosocial circumstances. The goal of therapy is to achieve a normal progression of physical changes of puberty to physical maturity and the normal potential for sexual function.

Ontogenic studies of the neural control of adenohypophyseal hormones in the rat: gonadotropins

1. Serotonergic, dopaminergic, and opioid systems controlling luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion develop with particular characteristics in the male and female prepubertal rats. 2. Serotonergic pathways evoke a maximal release of LH and FSH in female rats from day 12 to day 20 of age, but not in males of the same age. 3. Antidopaminergic drugs increase LH and FSH levels only in the female infantile rats. This effect is absent at birth and disappears after 20 days of age. 4. Naloxone markedly increases gonadotropins in 12-day-old females. 5. On the other hand, in 12-day-old male rats some neurotropic drugs such as diazepam could enhance LH levels, the effect being absent at other ages or in female littermates. 6. A period of high sensitivity of gonadotropins to neurotropic drugs is present during the second and third weeks of life of the rat and it is related to the sexual differentiation of the brain.

Luteinizing hormone and follicle stimulating hormone secretion patterns in girls throughout puberty measured using highly sensitive immunoradiometric assays

Pulsatile gonadotrophin secretion patterns were studied in 36 healthy girls by measuring every 10 min and applying immunoradiometric assays (IRMA). Different stages of puberty were associated with significant changes in the plasma LH and FSH levels, pulse numbers (Pno) and pulse amplitudes (pA). Plasma LH was not detectable by day or night in young prepubertal girls (B1), neither was plasma oestradiol (E2); however, plasma FSH was detectable in a pulsatile pattern. In the older prepubertal girls (B1-onset) a discrete pulsatile LH pattern became detectable only during the night; plasma FSH tended to rise, while E2 became just detectable. In the early pubertal girls (B2) most daytime LH values were above the detection limit, in some with low-amplitude pulses. At night, pulses with a wide range of pulse amplitudes were detected. Plasma FSH increased further, plasma E2 only slightly. With the progression of puberty the plasma LH and FSH levels, Pno and pA increased significantly from stage B2 to B3 during the day (P less than or equal to 0.05) and close to significance during the night (0.05 less than or equal to P less than or equal to 0.1). However, in stage B4 the secretory characteristics tended to decline, while from stage B3 onwards plasma E2 started to rise rapidly (P less than or equal to 0.05, during the night from stage B2 to B3, during the day from B3 to B4m-). Simultaneous LH and FSH pulses were observed throughout puberty, usually during the night. Using these IRMA methods nocturnal LH in older prepubertal girls and both diurnal and nocturnal FSH pulsatility could be demonstrated in young prepubertal girls. From this study we conclude that (1) puberty in girls, as in boys, may be brought about by an increasing GnRH secretion both in frequency and amplitude, first appearing during the night. This increased GnRH stimulation results in LH secretion only during the night; (2) a cyclical pulsatile LH pattern including an LH surge can be established before the menarche; the capacity for positive feedback activity is not the final maturation characteristic to achieve an ovulatory menstrual cycle.

Luteinizing hormone and follicle stimulating hormone secretion patterns in boys throughout puberty measured using highly sensitive immunoradiometric assays

Pulsatile gonadotrophin secretion patterns were studied in 32 normal boys (chronological age, CA 7.2-14.6 years) at different stages of pubertal development (5 in stage G1, 11 in G2, 5 in G3, 4 in G4, 7 in G5). Plasma LH and FSH concentrations were measured at 10 min intervals from 1200 to 1800 h and from 2400 to 0600 h using an immunoradiometric assay with a lower limit of detection of 0.15 IU/l for both LH and FSH. Plasma testosterone (T) was measured hourly. In the young prepubertal boys plasma LH was not detectable during day or night. In contrast, plasma FSH ranged from 0.7 to 1.4 IU/l. Plasma T was not detectable either (less than 0.25 nmol/l). In the older prepubertal boys a discrete pulsatile LH pattern (2 per 6 h) became discernible only during the night (range 0.1-0.4 IU/l). Plasma FSH also revealed a pulsatile pattern only during the night (2 per 6 h), while plasma T still remained undetectable. In the early pubertal boys (G2) a median daytime LH value of 0.37 IU/l was determined with 1 pulse per 6 h and at night definite LH pulses (4 per 6 h) were found in all boys (range 0.4-4.7 IU/l). Plasma FSH increased considerably to a median level of 2.50 IU/l during the day; most boys had a pulsatile FSH pattern (one per 6 h). Plasma T became detectable during the day (median 0.54 nmol/l) and night (median 1.16 nmol/l). With the progression of puberty the mean plasma level of LH and FSH, the LH/FSH pulse number and the LH/FSH pulse amplitude increased; plasma T rose as well, more obviously during the night. In G5, however, the LH pulse number decreased, while the LH level and pulse amplitude still increased, presumably as a result of the increased negative feedback action of sex steroids. Simultaneous LH/FSH pulses developed during the night at onset of puberty but during the day only towards the end of pubertal development. The use of these novel highly sensitive IRMA methods demonstrated nocturnal LH and both diurnal and nocturnal FSH pulsatility to be present in older prepubertal boys. The early detectable FSH level plus the existence of solitary FSH pulses throughout puberty as well as in adult men support the hypothesis of the existence of a GnRH-independent FSH secretion in men. Our results are in accordance with the following hypotheses: (1) puberty is brought about by GnRH secretion increasing with time, both in frequency and amplitude, and first appearing during the night.(ABSTRACT TRUNCATED AT 250 WORDS)

Rapid eye movement sleep deprivation depresses plasma FSH and LH in castrated rats

In castrated Wistar rats four days of Rapid Eye Movement sleep (REMs) deprivation by the cuff pedestal method induced decrements in plasma LH and FSH. The adenohypophyseal levels of these hormones were decreased in the REMs-deprived rats and in the control rats kept on pedestals with the supporting cuff in the elevated position as compared with the home-cage control rats. The results are discussed in terms of regional brain metabolic activity and transmission.

Immunohistochemical colocalization of delta sleep-inducing peptide and luteinizing hormone-releasing hormone in rabbit brain neurons

The anatomical distributions of luteinizing hormone-releasing hormone and delta sleep-inducing peptide immunoreactivity in the rabbit brain were studied by indirect immunofluorescence technique. The comparison of adjacent serial sections, one being immunolabeled with an antiserum to luteinizing hormone-releasing hormone, the other with an antiserum to delta sleep-inducing peptide, showed that the respective distribution patterns of immunoreactivity exhibited a remarkable overlap through the basal forebrain and hypothalamic regions. A sequential double-immunolabelling (elution-restaining method) clearly indicated that all the luteinizing hormone-releasing hormone-immunoreactive cell bodies displayed delta sleep-inducing peptide immunoreactivity. These cell bodies were sparse and mainly located throughout the septal-preoptico-suprachiasmatic region and the ventrolateral hypothalamus. The colocalization of luteinizing hormone-releasing hormone and delta sleep-inducing peptide immunoreactivity was also observed in many fibres supplying all these brain regions and terminal areas such as the organum vasculosum of the lamina terminalis, the subfornical organ, the median eminence and the pituitary stalk. These neuroanatomical findings are suggestive of interaction between delta sleep-inducing peptide and luteinizing hormone-releasing hormone in various brain areas including some circumventricular organs.

Effect of preovulatory estradiol concentrations on luteinizing hormone diurnal secretory patterns: a hypothesis for the timing of the luteinizing hormone surge

The effect of preovulatory estradiol concentrations on 24-hour patterns of luteinizing hormone secretion was studied in six women with normal menstrual cycles. Blood samples were collected every 15 minutes for 24 hours before and after 7 days of estradiol benzoate administration, which achieved mean (+/- SE) estradiol concentrations of 424 +/- 54 pg/ml. The luteinizing hormone pulse frequency decreased significantly during sleeping hours both before (p less than 0.05) and after (p less than 0.005) estradiol benzoate administration. After estradiol benzoate, there also was diurnal variation in overall mean luteinizing hormone concentrations, which markedly increased secretion in the morning hours. The diurnal changes in luteinizing hormone secretion varied inversely with those of prolactin. These findings are consonant with the observation that the onset of the preovulatory luteinizing hormone surge in women occurs most frequently in the early morning hours.

Pulsatile luteinizing hormone-releasing hormone treatment of male hypogonadotropic hypogonadism

Luteinizing hormone-releasing hormone (LH-RH) secretion from the hypothalamus follows a rhythmic pattern, inducing pulsatile luteinizing hormone (LH) and follicle-stimulating hormone (FSH) secretion from the pituitary gland. Consideration of this physiologic principle led to the introduction of pulsatile LH-RH therapy via infusion pump for the treatment of different forms of hypogonadotropic hypogonadism. We report on 10 male patients, 16 to 28 years of age, suffering from idiopathic hypogonadotropic hypogonadism (IHH) including Kallman's syndrome (n = 2) and delayed puberty (n = 2). All presented with complete eunuchoidism and had undergone no treatment for their conditions during the previous 2 years. LH-RH was administered in subcutaneous pulses of 4 to 16 micrograms, with a portable infusion pump (ZYKLOMAT, Ferring Corp., Kiel, FRG); treatment periods ranged from 6 to 24 months. With therapy, the subjects improved secretion of LH, FSH and testosterone. Testicular volumes and penis size increased; all patients developed normal secondary sexual characteristics. Spermatogenesis was induced in all patients. The time to onset of spermatogenesis ranged from 3 to 15 months. No major side effects were observed, and no patient dropped out of the study. The results indicate that pulsatile LH-RH therapy is an highly effective treatment for IHH and delayed puberty.

Reduced frequency of luteinizing hormone pulses in women with weight loss-related amenorrhoea and multifollicular ovaries

We have studied pulsatile secretion of LH in 10 women with secondary amenorrhoea and multifollicular ovaries (MFO). This group of patients have a history of mild to moderate, or partially recovered weight loss. They have normal basal LH concentrations but evidence of oestrogen deficiency suggesting a hypothalamic abnormality of gonadotrophin regulation. The results of gonadotrophin pulse analysis were compared with those in normal women during the early follicular phase of the cycle. The mean LH concentration during the 8 h study (5.0 +/- 0.9 [SD] U/l) was not significantly different from that in normal women (5.7 +/- 2.5). There was no difference between the groups in mean LH pulse amplitude (2.1 +/- 0.5 in MFO; 2.2 +/- 1.3 in normal women). The frequency of LH pulses was, however, significantly lower in women with MFO (2.8 +/- 1.6 vs 4.8 +/- 1.5, P less than 0.05). Two women with MFO had LH pulses of normal frequency. One subsequently developed a normal pattern of ovarian follicles. The other showed a sleep-related rise in LH concentrations during a 24 h profile which was similar to the pattern of gonadotrophin secretion normally observed during late puberty. These results show that women with MFO have a hypothalamic disturbance of gonadotrophin regulation with slowing of LH pulses without a diminution of pulse amplitude.

The mechanism of the adolescent growth spurt induced by low dose pulsatile GnRH treatment

We have used GnRH administered in a pulsatile fashion to treat 26 patients (12M:14F) with delayed puberty. Treatment was for a mean of 1.05 years (range, 0.3-1.6). Mean age at the onset of treatment was 16.4 years in the girls (range, 12.7-28.2) and 15.8 years in the boys (range, 13.8-17.8). At different stages of sexual maturation, overnight serum samples for growth hormone (GH) were taken at 15 min intervals between 2000 h and 0600 h. The girls had a peak growth velocity which occurred between breast stages 2 and stage 3 (B2/3). GH secretion (both sum of the GH peaks and area under the GH pulse) increased at B2 and reached a peak at B3. Growth acceleration in the boys started at the attainment of a 9-10 ml testicular volume and reached a peak at 11-15 ml. The boys demonstrated an initial fall in GH secretion with the onset of treatment until the attainment of 9-10 ml testicular volume; peak GH secretion occurred at the attainment of 11-12 ml testicular volume. There was no change in GH pulse frequency during treatment in either sex. These observations and the maintenance of the normal relationship of the growth spurts to the appearance of secondary sexual characteristics are relevant to the mechanisms and timing of the adolescent growth spurts in normal girls and boys.

Delta sleep inducing peptide (DSIP) stimulates the release of LH but not FSH via a hypothalamic site of action in the rat

Long term ovariectomized (OVX) Sprague-Dawley rats were injected intraventricularly (3rd ventricle) with 5 micrograms (2 microliter) of DSIP. This caused a significant elevation (p = 0.01) of LH levels within 30 min. The values remained elevated for 2 hr; however, FSH levels remained unchanged. The minimal effective dose of DSIP to evoke this effect was 1 microgram. If plasma PH was lowered by pretreatment of the animals with estradiol, the 5 micrograms dose evoked an even greater effect to elevate LH significantly at 30 and 60 min following its intraventricular injection. To determine the site of action of DSIP, dispersed, overnight cultured pituitary cells from OVX rats were incubated with varying concentrations (10(-7) to 10(-12) M) of DSIP in an in vitro system. There was no response to DSIP from the cells in the above system. To evaluate its possible action on the hypothalamus, median eminence (ME) fragments from male rats were incubated in vitro with DSIP in varying concentrations from 10(-7) to 10(-10) M. There was a significant (p less than 0.001) increase in LHRH released from the ME at a concentration of DSIP of 10(-7) M. A sleep-related increase in LH release is seen during puberty in man. It is possible that DSIP released within the hypothalamus may play a physiological role in sleep-related LH release.

Neuroendocrine control processes. Pubertal onset and progression

This discussion has outlined current concepts in neuroendocrinologic control of pubertal onset and progression. Central nervous system regulation of the arcuate nucleus (ventromedial hypothalamus) pulse generator that subsequently controls pituitary gonadotropin synthesis and secretion has been highlighted. Significant investigative issues that deserve assessment in the next several years include the following: 1. Systematic neuropharmacologic, electrophysiologic, and anatomic assessment of the hypothalamic arcuate nucleus. These assessments would include the use of recombinant DNA technology to probe cellular regulation of GnRH production. 2. Physiologically oriented examination of hypothalamic GnRH synthesis and secretion, along with function in the remaining reproductive endocrine system, during situations of nutritional impairment and excessive energy utilization and psychologic stress. 3. Further assessment of the neurophysiologic inhibition of GnRH production during childhood and the late prepubertal reactivation of the arcuate nucleus pulse generator. Roles of opioids, dopamine, other neurotransmitters, and metabolic signals remain to be clarified. 4. Exploration of regulators of hypothalamic, pituitary, and gonadal function when pulsatile GnRH administration has replaced the usual hypothalamic mechanisms. Pituitary-gonadal interactions may be independently assessed. 5. Assessment of pubertal growth, endocrine function, and neuropharmacologic control mechanisms in circumstances of chemical removal of pituitary gonadotrope function by GnRH agonists or antagonists. 6. Concordance and discordance of potency estimates of gonadotropins made by bioassay and immunoassay. The biologic basis for qualitative changes in bioassayable levels of LH and FSH, often related to carbohydrate content of the glycoprotein, may help to explain changes of gonadal function during the pubertal process. The potential for significant molecular heterogeneity of the gonadotropins is recognized and suggests substantial posttranslational changes of LH and FSH. 7. A cogent delineation of the hormonal, nutritional, and energy regulators of the pubertal growth spurt, though not discussed in this manuscript, remains to be accomplished. The relationship between pituitary gonadotropins and growth hormone, sex steroids, and the various peptide growth factors, especially the relationship between the growth factors and intragonadal steroidogenesis and germ-cell production, remain to be resolved. The importance of local production and action of peptide-growth factors in diverse tissues, skeletal and other, is being increasingly recognized.(ABSTRACT TRUNCATED AT 400 WORDS)

Induction of puberty by pulsatile gonadotropin releasing hormone

15 girls and 17 boys with delayed or arrested puberty were treated with gonadotropin releasing hormone (GnRH) for a mean of 1.04 years. GnRH was administered subcutaneously in a pulsatile fashion at 90 min intervals, and the dose was increased as required to maintain progression of puberty, initially only at night and subsequently over 24 h. Initial GnRH dose was 1-2 micrograms per pulse in the girls and 2-4 micrograms per pulse in the boys. The effect of treatment was monitored by serial overnight gonadotropin profiles in all patients and with pelvic ultrasound in the girls. The clinical features, growth acceleration, endocrinology, and ovarian ultrasound morphology of puberty were those seen in normal children. Measurement of spontaneous gonadotropin pulsatility after treatment had been discontinued allowed the distinction between 20 patients with hypogonadotropic hypogonadism and 12 who had constitutional delay of growth and puberty. 2 girls and 6 boys did not respond to the treatment regimen. These findings indicate that normal puberty is GnRH dependent.

Delta sleep-inducing peptide (DSIP) stimulates LH release in steroid-primed ovariectomized rats

Delta sleep inducing peptide (DSIP) has been shown to increase sleep in various animals and it is found in various parts of the brain including the hypothalamus. While intraventricular administration of DSIP (2 or 10 micrograms) failed to affect LH release in ovariectomized rats, in two separate experiments DSIP (2 or 10; 15 or 30 micrograms) promptly stimulated LH release in ovariectomized estrogen, progesterone-primed rats. However, DSIP (10(-8) or 10(-6)M) had no effect on either basal or luteinizing hormone-releasing hormone-induced in vitro LH release from the hemipituitaries of ovarian steroid-primed rats. These findings are in accord with the hypothesis that DSIP or DSIP-like peptide(s) may activate the hypothalamic neural circuitry responsible for stimulation of LH release reported to occur during sleep.

Studies of gonadotrophin pulsatility and pelvic ultrasound examinations distinguish between isolated premature thelarche and central precocious puberty

We have studied the pulsatile secretion of gonadotrophins at night and made ovarian ultrasound examinations in three girls with central precocious puberty and three with isolated premature thelarche. The three girls with precocious puberty had well-defined pulsatile secretion of LH and FSH with LH predominating, as would be expected in normal puberty. Pulsatile secretion of gonadotrophins was also seen in girls with premature thelarche but the pattern was reversed. In girls with precocious puberty, large "multicystic" ovaries and large uteri were seen on ultrasound examination, whereas girls with isolated premature thelarche had small uteri and ovaries with less than four "cysts" up to 15 mm in diameter. These data provide the key to understanding the aetiology of isolated premature thelarche.

Sleep EEG in growth disorders

The sleep of 30 children with disorders of growth and development was studied because of the known association between sleep and the secretion of hormones. Thirty three normal children were studied for comparison. The sleep of two consecutive nights was monitored at home using a small portable electroencephalogram and electro-oculogram recorder. Within the normal group there were no significant differences between sexes nor between the first and second nights of recording. There was a significant decrease in total sleep time with increasing age due to reduction in the amounts of rapid eye movement sleep and stage IV sleep. There was no change in rapid eye movement latency or overall rapid eye movement activity between the three age groups. Children with genetic short stature and those with poor growth as a result of poor eating habits had an increased percentage of rapid eye movement sleep. A significant decrease in the percentage of stage IV sleep, increased amount of rapid eye movement sleep (especially active rapid eye movement sleep), and decreased rapid eye movement cycling time was found in five children with severe psychosocial deprivation. Children with constitutional delay of growth and puberty had an increased rapid eye movement cycling time and thus less rapid eye movement sleep over the whole night.

Multifollicular ovaries: clinical and endocrine features and response to pulsatile gonadotropin releasing hormone

By means of pelvic ultrasonography, a multifollicular ovarian appearance was observed in women with weight-loss-related amenorrhoea. Multifollicular ovaries (MFO) are normal in size or slightly enlarged and filled by six or more cysts 4-10 mm in diameter; in contrast to women with polycystic ovaries (PCO), stroma is not increased. Unlike PCO patients, women with MFO were not hirsute and serum concentrations of luteinising hormone and follicle stimulating hormone were normal and decreased, respectively. The uterus was small indicating oestrogen deficiency. In MFO, treatment with gonadotropin releasing hormone (LHRH) induced ovulation in 83% of cycles and there were seven pregnancies in 8 women; in PCO, only 40% of cycles were ovulatory and there were eleven pregnancies (8 women) but six of these aborted. In MFO ovarian morphology reverted to normal in ovulatory cycles, whereas in PCO the polycystic pattern persisted despite the presence of a dominant follicle. MFO may represent a normal ovarian response to weight-related hypothalamic disturbance of gonadotropin control.

Spontaneous gonadotrophin pulsatility and ovarian morphology in girls with central precocious puberty treated with cyproterone acetate

We have studied four girls with central precocious puberty treated with cyproterone acetate for a mean of 3.6 years (range 1.5-6.3 years). Pelvic ultrasound assessment demonstrated suppression of the ovarian morphology of central precocious puberty despite the presence of spontaneous pulsatile gonadotrophin secretion at night. We suggest that the previously reported effects on gonadotrophin secretion induced by cyproterone acetate therapy, administered in recommended doses, are minor and that the predominant effect of cyproterone acetate in the treatment of girls with central precocious puberty is direct inhibition of ovarian steroidogenesis.

The treatment of central precocious puberty using an intranasal LHRH analogue (buserelin)

Eight girls and one boy with precocious puberty were treated with intranasal (D-Ser6)-LHRH (buserelin) for 0.5-2.3 years (mean 1.2 years). Treatment regimen varied between 17 and 40 microgram/kg/d in the girls to 10 micrograms/kg/d in the boy in two or three divided doses. Gonadotrophin-dependent clinical signs showed arrest or regression whereas those of adrenarche progressed. Serial pelvic ultrasound assessment was used to monitor treatment in four girls. Although peak stimulated gonadotrophins reduced to prepubertal levels, basal gonadotrophins became elevated on treatment. The mode of action of buserelin was the abolition of gonadotrophin pulsatility. Initial data suggest an improved growth prognosis. We concluded that intranasal therapy is an alternative route of administration of LHRH analogue in the treatment of precocious puberty.

Ovarian ultrasound assessment in normal children, idiopathic precocious puberty, and during low dose pulsatile gonadotrophin releasing hormone treatment of hypogonadotrophic hypogonadism

Ultrasound assessment of ovarian volume, follicular size, and uterine growth was undertaken in 40 normal premenarcheal girls aged 6 months to 14 years. Ovarian follicles were detected from 6 months of age and increased in size and number, so that after the age of 8.5 years there was a progressive increase in the incidence of 'megalocystic' appearance. Eight girls with idiopathic precocious puberty had large megalocystic ovaries which regressed on treatment with gonadotrophin releasing hormone analogue. These findings contrasted with those seen in two prepubertal patients with hypogonadotrophic hypogonadism in whom the natural sequence of ovarian development was greatly accelerated by pulsatile administration of native gonadotrophin releasing hormone.