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Biomedical subjects

H Friesen

Publications and source records attributed to H Friesen.

At least 37 records · Page 2Linked to original sources
PubMed1980

Concentrations of placental lactogen in chronically catheterized ewes and fetuses in late pregnancy.

The concentration of ovine placental lactogen (oPL) was measured by radioimmunoassay in plasma samples from chronically catheterized ewes and their fetuses from day 110 of gestation to term (about day 145). Concentrations of oPL in the plasma of the mother and fetus were raised after surgery, and remained raised for 3--5 days after the operation. Concentrations of oPL were greatest in the fetus at days 120--124 of gestation, and then declined until delivery. Mean concentrations of oPL in the fetus in late pregnancy for single, twin and triplet pregnancies were 101 +/- 6 (S.E.M.), 100 +/- 11 and 115 +/- 59 ng/ml respectively and were not significantly different. Mean concentrations of oPL in the mother in late pregnancy for single, twin and triplet pregnancies were 718 +/- 227, 1387 +/- 160 and 1510 +/- 459 ng/ml respectively; the difference between these means was significant (P less than 0.05). Peak concentrations were noted at days 130--139 of gestation after which concentrations fell and were significantly lower on the day of delivery (P less than 0.01). Concentration of oPL in the mother showed no circadian rhythm. The mean concentrations of oPL in maternal plasma during late pregnancy was significantly correlated to the combined fetal weight at birth (r = 0.624, P less than 0.01).

Animals↗
PubMed1979

Hepatic-portal glucose and insulin levels: relationship to glucose-induced satiety and hunger.

The hepatic-portal infusions of both smaller and larger glucose loads, which had no significant effect on food intake in chronic feeding experiments, produced only a brief dose-dependent peak-like elevation in glucose and insulin levels. In contrast, metabolic changes produced by duodenal infusions were greater and considerably longer in duration. The maximal level and duration of glucose and insulin increase further differentiated two feeding phenomena induced by duodenal infusions: 1) the metabolic satiety of smaller glucose loads associated with blunted and delayed glucose and insulin increases within normal physiological range; 2) paradoxical antiregulatory stimulation of food intake induced by larger glucose loads associated with a gradually intensified, exaggerated and prolonged insulin increase. This increase was significantly larger than corresponding preinfusion value even at the end of 3 hour test period. Present results thus demonstrate that various glucose-induced feeding phenomena are associated and apparently dependent for their expression on distinct, prolonged changes in glycemia and insulin levels.

Animals↗
PubMed1978

Opiate-like naloxone-reversible actions of somatostatin given intracerebrally.

The latency to tail-flick response in the rat was significantly prolonged by cerebroventricular infusion of 1.0 microgram of somatostatin (SRIF) and more so with 10.0 microgram. The D-tryptophan analog was less effective than native SRIF. Pretreatment with naloxone eliminated analgesia but not seizures induced by SRIF. Recording of the EEG activity enabled determination of the specific state of the sleep-waking cycle in which the repeated tail-flick responses were tested: latency was generally longer in both control and test animals when tail immersion was performed during the state of sleep or drowsiness rather than during the awake state. Although animals receiving SRIF were less likely to fall asleep between subsequent test trails, the average latency was actually longer than after control saline infusion when the animals slept more. SRIF, unlike other releasing factors and peptides tested, showed significant activity in an opiate radioreceptor assay. The blockade of SRIF action by naloxone pretreatment, along with binding of SRIF to opiate receptors in vitro, suggest opiate receptors to be involved in the mediation of analgesia observed in present study.

Animals↗
PubMed1977

The release of prolactin by medroxy-progesterone acetate in human subjects.

Medroxyprogesterone acetate an injectable contraceptive when administered to four lactating women at a dose of 150 mg every three months significantly raised prolactin levels over those observed in four control women. Prolactin levels were higher at all times during 4-17 weeks in the drug-treated women, irrespective of whether the samples were collected before or after suckling. It was also observed that while suckling clearly released prolactin in both groups the difference was greater in the women receiving the injection, indicating that the drug enhanced the release of prolactin in response to the suckling stimulus.

Adult↗
PubMed1977

Neostriatal administration of somatostatin:differential effect of small and large doses on behavior and motor control.

The administration of small doses of somatostatin (SRIF) (0.01 and 0.1 microgram) into the neostriatal complex of unrestrained, freely moving rats induced general behavioral excitation associated with a variety of stereotyped movements, tremors, and a reduction of rapid eye movements (REM) and deep slow wave sleep (SWS). In contrast, the higher doses of SRIF (1.0 and 10.0 microgram) caused movements to be uncoordinated and frequently induced more severe difficulties in motor control such as contralateral hemiplegia-in-extension which restricted or completely prevented the expression of normal behavioral patterns. As a result, the animals appeared drowsy and inhibited. Analysis of the sleep-waking cycle revealed prolonged periods of a shallow SWS while REM sleep and deep SWS were markedly reduced; electroencephalogram recordings revealed periods of dissociation from behavior. The administration of endocrinologically inactive as well as the active analogues of SRIF failed to induce effects comparable with those observed after the administration of the same dose of the native hormone (10.0 microgram).

Animals↗
PubMed1976

Somatostatin and thyrotropin releasing hormone: central effect on sleep and motor system.

The hypothalamic hormones, somatostatin (SRIF or GH-RIH) and thyrotropin releasing hormone (TRH) applied intraventricularly into rat brain had a considerable effect on motor function and resulted in profound alterations in the sleep-waking pattern. While TRH induced primarily an increase in exploratory and motor stereotyped behavior, the effect of somatostatin was striking and prolonged: stereotyped circular running in many instances evolved into catatonia, paraplegia-in extension and/or tonic-clonic seizures.

Animals↗
PubMed1976

Cortical administration of somatostatin (SRIF): effect on sleep and motor behavior.

Cortical administration of SRIF in unrestrained, freely moving rats produced an early activation, stereotyped behavior patterns and later, coordination difficulties often associated with drowsiness. A few animals showed a tendency toward paraplegia-in-extension. A considerable, prolonged alteration in the sleep-waking cycle was also observed. Similar results were obtained in both intact and hypophysectomized animals. Intraperitoneal administration of SRIF induced several other effects in addition to those seen after cortical application. The latter were however, restricted in variety, intensity and duration.

Animals↗
PubMed1975

Lack of action of prolactin suppression on the regulation of the human menstrual cycle.

Bromocriptin (CB 154) has been found to suppress established lactation at a time when human plasma prolactin (HPRL) concentrations have already returned to the nonpregnant range. This action is due to inhibition of prolactin from the pituitary. It was then thought that a similar degree of inhibition induced during the menstrual cycle may help to uncover other possible biological actions of prolactin. In an attempt to elucidate this question eight breast-feeding mothers and seven normally menstruating volunteers underwent treatment with CB 154, including blood sampling during a sleep period. The dosage was 1 mg., three times daily, for 14 days in the first group and for a whole cycle in the normal volunteers. A control cycle preceded drug administration in the latter group. Prolactin (HPRL), growth hormone (HGH), luteotropin (LH), progesterone (PG), and estradiol (E2) were estimated (mean +/- standard error) along the menstrual cycles in the normal volunteers. HPRL and milk volumes were measured in the breast-feeding women in the base-line period and during treatment. In the postpartum group, basal HPRL had already reached normal levels prior to therapy (10.8 +/- 1.0 ng. per milliliter) and was significantly (p less than 0.002) depressed to 3.7 +/- 0.4 ng. per milliliter by CB 154. This degree of inhibition was effective in suppressing lactation within 24 to 48 hours in all of the subjects in that group. The fall in plasma HPRL from 9.5 +/- 1.5 ng. per milliliter to 3.2 +/- 0.2 ng. per milliliter observed in the normally menstruating women was similar to the one recorded in the breast-feeding group, but the sequence of hormonal changes during the menstrual cycle was not altered by treatment. The overnight study ensured around-the-clock prolactin inhibition. Results indicate no action of prolactin in the regulation of the human menstrual cycle at levels of inhibition at which a biological action of this hormone is clearly suppressed.

Adult↗
PubMed1975

Medical Research Council of Canada therapeutic trial of human growth hormone: first 5 years of therapy.

The Medical Research Council of Canada has initiated human growth hormone (hGH) therapy in 151 patients with documented complete hGH deficiency that was idiopathic in 76% of cases, secondary to craniopharyngioma (organic) in 17% and of varied cause in 7%. Approximately 50% of the patients with idiopathic disease had isolated hGH deficiency; during therapy thyroid deficiency developed in five patients and cortisol deficiency in three. A similar increase in mean height velocity occurred in the first treatment phase for patients less than 12 years old (0.93 plus or minus 0.30 cm/mo) and those 12 years and older (0.86 plus or minus 0.29 cm/mo). Although subsequent courses of hGH therapy yielded significantly diminished response in both age groups, this diminution was not progressive: the height velocity of the younger patients returned to 0.82 plus or minus 0.26 cm/ml in the fifth therapy phase. The mean height velocity attained at the optimal dosage (0.20 to 0.29 units/kg three times per week) for each age group did not differ significantly. Despite therapy being carried out for only 6 months of the year, normal increment ratios for height age and bone age against chronologic age were observed in the patients with idiopathic disease. In only four patients did treatment failure occur, and three of these were more than 20 years old. The addition of fluoxymesterone (10 mg/d) to the hGH therapeutic regimen (15 units/wk), when diminished response to hGH alone became evident, promoted an enhanced growth response in 9 of 11 older patients. These data indicate that age of the patient and dosage of hGH, but not diagnostic category, were important influences on the response to therapy. Younger patients responded best and maintained a higher mean growth velocity than older patients during intermittent hGH therapy

Adolescent↗
PubMed1975

Dynamic evaluation of growth hormone (GH) and prolactin (hPRL) secretion in active acromegaly with high and low GH output.

Ten patients with active acromegaly were studied. In 9 plasma GH levels failed to suppress after glucose (OGTT), in 8 an increase in serum GH occurred after thyrotropin releasing hormone (TRH). After L-Dopa, 4 patients showed no change in serum GH, 3 exhibited a decrease and in 3 an increase in serum hGH occurred. With a combined insulin (ITT) and arginine (ATT) test, 2 patients exhibited an increase in hGH, and in 6 no change occurred. Fasting serum GH concentration was less than 11 ng/ml in 5 patients. Basal prolactin (hPRL) levels were normal in all patients including two with galactorrhea. L-Dopa suppressed and TRH stimulated hPRL secretion in all, but the responses which were seen were subnormal. Hydrocortisone infusion in two acromegalics did not affect the prolactin induced increase after TRH but blunted the GH increase after TRH.

Acromegaly↗