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Biomedical subjects

E D Weitzman

Publications and source records attributed to E D Weitzman.

At least 91 records · Page 5Linked to original sources
PubMed1975

Altered growth of hormone secretory pattern following prolonged sleep deprivation in the rhesus monkey.

Plasma concentrations of growth hormone (GH) were determined in samples obtained sequentially at 15-min intervals during the last 4 h in monkeys deprived of sleep for 76 h and the first 8 h of ensuing recovery sleep. Electroencephalographic (EEG), electro-oculographic (EOG), and electromyographic (EMG) activities were recorded. Stages 3-4 sleep occurred rapidly after sleep onset and were of long duration. Plasma GH secretion was markedly elevated during sleep recovery, without apparent relationship to stage of sleep.

Animals↗
PubMed1975

Twenty-four-hour secretory patterns of gonadotropins and prolactin in a case of Chiari-Frommel syndrome.

Plasma LH, FSH and prolactin secretory patterns were derived from the measurement of 20-min interval plasma samples obtained during a complete 24-h period in a patient with persistent postpartum amenorrhea and galactorrhea (Chiari-Frommel syndrome), before and after clomiphene citrate therapy. During nocturnal sleep, polygraphic monitoring was carried out to precisely identify sleep onset, specific sleep stages and waking periods. During the evening and nighttime hours, LH and FSH concentrations were markedly reduced, compared to the daytime patterns both before and after clomiphene therapy. A sleep associated rise of prolactin concentration was present, similar to the pattern found in normal subjects but at higher concentrations. The reciprocal nature of the nocturnal secretory patterns for LH and FSH and prolactin in this patient suggests an alteration in hypothalamic dopaminergic mechanisms which are thougt to control the secretion of these hormones.

Adult↗
PubMed1975

Seasonal patterns of sleep stages and secretion of cortisol and growth hormone during 24 hour periods in northern Norway.

A group of 7 healthy male subjects was studied in regard to sleep stages and 24 h plasma cortisol and growth hormone patterns during the 4 seasons of the year in an Arctic environment (Tromsø, Norway). No difference in total sleep or sleep stage per cents was found for any of the yearly seasons. A small but statistical significant increase in mean plasma cortisol concentration and amount secreted for 24 h was found for the autumn-winter seasons, as compared with the spring and summer. However, no difference in the circadian curve of cortisol hormonal pattern was found. All subjects secreted growth hormone shortly after sleep onset at night and no difference was found as a function of season of the year.

Adult↗
PubMed1975

The circadian rhythm of the intraocular pressure in the New Zealand White rabbit.

Most physiologic functions in man as well as in animals have been shown to have a circadian (approximately 24 hour) rhythm. It has been found in both the normal and glaucomatous human eye that the intraocular pressure, which is one of these circadian functions, varies considerably over a 24-hour period. Because of the extensive use of the rabbit in glaucoma research, a detailed study of the intraocular pressure over a 24-hour period was undertaken. Using hourly applanation tonometry for 25 consecutive measurements in ten New Zealand White rabbits (20 eyes), a circadian rhythm of the rabbit intraocular pressure was found. The pressures were lowest at night and rose to their highest values during the day. In addition, the data suggest that the maximum intraocular pressure may be biphasic with maximum values occurring between 0800 and 1100 and 1600 and 1900. Therefore, studies involving the New Zealand White rabbit must take into consideration these 24-hour pressure changes when intraocular pressure measurements are made.

Animals↗
PubMed1974

Hypothalamic-pituitary function in diverse hyperprolactinemic states.

Prolactin secretion in normal adults is characterized by periods of episodic secretion which increase in magnitude during sleep. In this study, we report the 24-h mean prolactin concentrations, prolactin secretory patterns, and associated pituitary hormone function in nine patients (seven women and two men) with hyperprolactinemia of diverse etiologies. Four of the women and one of the men had clinically demonstrable pituitary tumors, one boy had a hypothalamic tumor, and the three other women had "functional" hyperprolactinemia. The 24-h mean prolactin concentrations derived from averaging the 20-min interval samples for 24 h ranged from 28.6 to 1,220 ng/ml. The plasma prolactin patterns in these patients showed persistence of episodic secretion in all and loss of the normal sleep-wake difference in plasma prolactin in seven of nine. Three of the patients with galactorrhea and comparable 24-h mean prolactin concentrations (58.3, 59.7, and 64.3 ng/ml) showed similar prolactin secretory patterns despite different etiologic mechanisms. Evaluation of the secretory patterns of luteinizing hormone (LH) in these patients showed loss of normal pulsatile LH release and a low 24-h mean LH concentration in the patient with the pituitary tumor, while the two patients without clinically demonstrable pituitary tumors ("post-pill" galactorrhea and "idiopathic" galactorrhea) showed normal LH secretory patterns and 24-h mean LH concentrations. The 24-h mean cortisol concentrations and secretory patterns were normal in five of the seven patients who had these parameters measured. The patient with the hypothalamic tumor had a low 24-h mean cortisol concentration and production rate and absent response to metyrapone. The patient with "idiopathic" galactorrhea had an elevated 24-h mean cortisol concentration but normal cortisol production rate and urinary 17-hydroxycorticoid excretion. Growth hormone secretion was abnormal in four of the patients (one with the hypothalamic tumor and three with pituitary tumors). Thyrotropin-releasing hormone (TRH) administration in four patients resulted in normal TSH release in two patients (one of whom developed galactorrhea after the test), an absent response in the patient with the hypothalamic tumor, and a blunted response in one of the women with a pituitary tumor. The two men had low 24-h mean plasma testosterone concentrations (69 and 30 ng/100 ml) and symptoms of impotence and loss of libido. Five of the women (four with pituitary tumors and one with Chiari-Frommel syndrome) had either low 24-h mean LH concentrations, abnormal LH secretory patterns, or both. These data indicate that patients with hyperprolactinemia encompassing a varied etiological range frequently show loss of the normal sleep-associated increase in prolactin secretion as well as abnormalities in the regulation of the other hypothalamic pituitary-regulated hormones. The finding that the abnormalities in LH, growth hormone, thyrotropin, and cortisol (adrenocorticotrophic) secretion were almost uniformly confined to the patients with the clinically demonstrable hypothalamic or pituitary tumors suggests that the size of the lesion is the critical factor.

17-Hydroxycorticosteroids↗
PubMed1974

Human puberty. Simultaneous augmented secretion of luteinizing hormone and testosterone during sleep.

Plasma luteinizing hormone (LH) and testosterone (T) were measured by radioimmunoassay in nine pubertal boys and three sexually mature young men at 20-min intervals for 24 h. Plasma LH and T were also measured in one boy during a delayed sleep onset study. Polygraphic monitoring was carried out to identify precisely sleep onset. Wakefulness, and specific sleep stages. In all nine pubertal boys the plasma T concentration fluctuated and was significantly higher during normal nocturnal sleep as compared to daytime waking. This increased T secretion during sleep was temporally linked to the characteristic pubertal sleep augmentation of LH secretion. To define further the relationship of this increased T secretion to sleep, plasma LH and T were also measured in three of the pubertal boys after acute (1-day) reversal of the sleep-wake cycle. One of these boys was also studied after 3 days of sleep-wake cycle reversal. The results of these studies showed that plasma T was now augmented during the reversed daytime sleep period; the mean T concentrations during this period were significantly higher (P < 0.001) than during nocturnal waking in all four studies. Measurement of plasma LH and T in the three sexually mature young men showed episodic secretion of LH and T during both waking and sleep periods; there was no consistent significant augmentation of LH or T secretion during sleep. This study demonstrates that (a) in normal pubertal boys and sexually mature young men plasma T fluctuates episodically; (b) there is marked augmentation of T secretion during sleep in pubertal boys, which is dependent on increased LH secretion; (c) this pubertal LH-T secretory "program" is dependent on sleep, since it shifts with delayed sleep onset and reversal of the sleep-wake cycle; and (d) this demonstrable tropic effect of LH on T is evident only during puberty, since sexually mature young men fail to show any consistent relationship between LH and T secretion either awake or asleep.

Adolescent↗