Moravian missionaries recorded all births in two Eskimo communities in northern Labrador from 1778 to 1940. These records demonstrate an annual cycle in births characterized by a peak in March, a trough in June, with an amplitude of 80%; they agree with previous observations on seasonal breeding among the Eskimo made by early Arctic explorers.

Birth Rate↗

PubMed1983

Episodic hyperhidrosis, hypothermia, and agenesis of corpus callosum.

Episodic hyperhidrosis and hypothermia are the primary symptoms of a rare central nervous system disorder of thermoregulation which is often associated with agenesis of the corpus callosum and can present in childhood or adult years. During attacks, patients may exhibit confused, withdrawn, and lethargic behavior and ataxia or other neurologic symptoms. A 21-year-old man with temperature chronically between 30 and 32 degrees C transiently responded to phenobarbital and to cyproheptadine therapy. A 34-year-old woman with frequent, brief episodes of hypothermia and hyperhidrosis improved with chlorpromazine treatment. Episodic thermoregulatory disturbance has been attributed to "vagal attacks" or "diencephalic epilepsy," but the pathophysiology remains undefined.

Adult↗

PubMed1982

TRH and spinocerebellar degeneration.

Explore the source record for details and available documents.

Animals↗

PubMed1982

Daily rhythm of plasma melatonin in normal and precocious puberty.

A previous study of normal humans has shown a decrease in plasma melatonin at the onset of puberty, suggesting that melatonin may act to restrain pubertal onset. We have measured plasma melatonin throughout a 24-h period in normal and constitutionally short males at different pubertal stages and in patients with idiopathic true precocious puberty and familial male isosexual precocity. The 24-h profile of plasma melatonin was similar for the prepubertal, pubertal, and adult males studied, with all subjects having low levels (20-50 pg/ml) during the day and high levels (80-100 pg/ml) at night between 0100-0500 h. The 24-h profiles of the patients with isosexual precocity were similar to the profiles observed throughout normal puberty. These data do not support a role for melatonin in the initiation of normal or precocious puberty in man.

Adolescent↗

PubMed1978

Neuroendocrine mechanisms mediating the suppression of circulating testosterone levels associated with chronic stress in male rats.

Neuroendocrine mechanisms involved in the reduction of testosterone (T) levels induced by the chronic surgical stress of s.c. gauze implantation were investigated in male rats. The reduction resulted from a decline in T secretion and not an increase in clearance of the hormone from the circulation. In most cases, the decrement was accompanied by a reduction in LH levels, indicating that decreased LH stimulation is the primary factor mediating the drop in T levels. The suppressive effect of surgical stress on LH and T levels was apparently not mediated by the pituitary-adrenal system.

Adrenal Glands↗

PubMed1976

Effects of sex steroids on serotonin uptake in blood platelets.

Blood platelets have been suggested as amodel for serotonin uptake and storage in the brain. To examine possible effects of se- steroids, platelets from human volunteers were incugated for 15 min with oestradiol, testosterone, and dihydrotestosterone, and then incubated fro 1 min with radioactive serotonin. The effects of the various steroids on serotonin uptake were measured. At 10(-3) M, oestradiol decreased serotonin uptake by 70%, testosterone by 49%, and dihydrotestosterone by 25%. Both oestradiol and testosterone showed maximal enhancement of uptake at 10(-6) M; oestradiol increased serotonin uptake by 41%, and testosterone by 60%. Dihydrotestosterone maximally facilitated uptake by 40% at a concentration of 10(-4) M. No sex differences were found in either direction or in magnitude of change in uptake due to any hormone. It is suggested that the effects of oestradiol are of physiological significance and that the site of action of the sterioid effect on serotonin uptake is the cell membrane of the platelets.

Blood Platelets↗