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Biomedical subjects

L Hellman

Publications and source records attributed to L Hellman.

At least 109 records · Page 6Linked to original sources
PubMed1975

Preparation and antigenic properties of androsterone-7-BSA conjugate.

The 7-carboxymethoximino derivative of androsterone (1) has been prepared from dehydroisoandrosterone-17-ethyleneketal by a sequence involving inversion at C-3, introduction of a carbonyl at C-7, and reduction of the double bond at C-5. The substance was condensed with BSA by the carbodiimide procedure to afford a conjugate which produced anti-androsterone antiserum in innoculated rabbits. The antiserum is sufficiently active to be useful in radioimmunoassay procedures.

Androsterone↗
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

24-Hour secretory pattern of dehydroisoandrosterone and dehydroisoandrosterone sulfate.

Dehydroisoandrosterone (DHA) and cortisol were measured by radioimmunoassay and protein binding techniques respectively in plasma from blood taken at 20-min intervals over 24-h periods in 3 normal men, 2 women with Stein-Leventhal syndrome and a man with a benign adrenocortical adenoma. In all subjects but the latter, DHA and cortisol were episodic and synchronous throughout the entire day; in this patient, continuous secretion of cortisol by the tumor apparently abolished stimulation of the contralateral adrenal, and DHA production was negligible. Dehydroisoandrosterone sulfate analysis in plasma displayed a pattern which, probably because of its origin both by secretion and sulfation and its long half-life showed less synchronicity with DHA and cortisol and less fluctuation than did the free hormones.

Adenoma↗
PubMed1975

Twenty-four hour prolactin (PRL) secretory patterns during pregnancy.

To determine if the central nervous system "program" controlling PRL secretion is operative during pregnancy, three pregnant women (12th, 20th and 32nd week of gestation) had 24-hour, 20-minute interval plasma sampling and polygraphic monitoring of nocturnal sleep. All three subjects showed episodic PRL secretion during waking which became augmented during nocturnal sleep. Since the number of "major" PRL secretory episodes was similar to normals, the increased PRL levels were most probably achieved by increased secretion per secretory episode. These findings suggest that during pregnancy, the PRL sleep related secretory "program" is maintained in a qualitative manner, albeit at a higher set-point.

Adult↗
PubMed1975

Influence of body weight on estradiol metabolism in young women.

The metabolism of estradiol in girls with anorexia nervosa was compared with obese subjects and normal weight, age and sex matched controls. Increasing body weight was accompanied by a sharp decrease in 2-hydroxylation of estradiol and an increase in 16alpha-hydroxylation. These metabolic changes are discussed in terms of the biological activity of 2-hydroxyestrone and estriol.

Adolescent↗
PubMed1975

Changes in estradiol and cortisol production rates in men under the influence of narcotics.

The production rates of estradiol and cortisol in two male opiate addicts while on narcotic maintenance, were in the low normal or subnormal range. There was a sharp several-fold increase upon withdrawal with a subsequent fall to normal values after a period of abstinence. The changes in estradiol production rates were proportionally greater than those of cortisol and suggest that they were due to changes in testicular secretion of the precursor testosterone.

Adrenal Glands↗
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

Hormone profiles in hormone-dependent cancers.

Studies on the relationship of urinary excretion of androgen metabolites and estrogens to the natural history of breast cancer are reviewed. The importance of distinguishing between "within-population" studies (i.e., cancer patients versus normal controls) and "between populations" studies (i.e., low-risk versus high-risk populations) is emphasized, and it is pointed out that "qualitative" agreement (i.e. the same direction of differences) between the two types of studies must be present in order to implicate a hormonal parameter as a determinant of the natural history of breast cancer. For reasons detailed in this paper, it is concluded that the reported relationship of low urinary androgen metabolite excretion to increased risk of developing breast cancer and poor response to adrenalectomy or hypophysectomy and the validity of the "estriol hypothesis," namely, that a high urinary ratio of estriol to estrone-plus-estradiol in early life is protective against subsequent development of breast cancer, are both dubious. A new hypothesis concerning the relationship of estrogens to breast cancer risk is presented: "A period of of time, prior to age 30, during which the amount of biological availability of active estrogens' (i.e., estrone and estradiol) is diminished, protects against subsequent development of cancer." This hypothesis is shown to be compatible with the epidemiological and biochemical data. Reports concerning the influence of nutrition on endocrine parameters are reviewed. Inanition and obesity have been shown to alter steroid metabolism but it is not known whether nutritional "microdifferences" (i.e., differences between populations or individuals that are due to cultural, geographic, or socioeconomic factors, but that fall within the range of "normal" or adequate nutrition) can also alter steroid metabolism.

Adrenalectomy↗
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↗