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Biomedical subjects

G C Lachelin

Publications and source records attributed to G C Lachelin.

At least 37 records · Page 2Linked to original sources
PubMed1982

Plasma noradrenaline and adrenaline levels in normal pregnancy and in pregnancy-induced hypertension.

Plasma concentrations of noradrenaline and adrenaline were measured serially during normal pregnancy in 52 women who remained normotensive and in nine who developed pregnancy-induced hypertension but were otherwise normal. There was a significant fall in both noradrenaline (P less than 0.005) and adrenaline (P less than 0.05) levels during normal pregnancy. Throughout pregnancy the mean levels of both catecholamines were lower in the patients who developed pregnancy-induced hypertension than in the normotensive patients. There was no evidence of increased sympathetic nervous system activity in the women who developed pregnancy-induced hypertension.

Adult↗
PubMed1982

Long term effects of nightly dexamethasone administration in patients with polycystic ovarian disease.

The long term effects of nightly dexamethasone administration on basal levels and diurnal fluctuations of circulating gonadotropins, androgens, and cortisol were studied by frequent sampling in four women with polycystic ovarian disease and a similar number of normal women. Basal LH, testosterone, and androstenedione levels were elevated in the patients with polycystic ovarian disease. There were significant diurnal variations of all steroids measured in both groups, with the exception of androstenedione and androstenediol in the polycystic ovarian disease and control subjects, respectively. Nightly dexamethasone administration for 1 month resulted in marked suppression of dehydroepiandrosterone, androstenediol, and cortisol. For testosterone the mean percent decreases of the 24-h transverse means were 15% and 46% for the polycystic ovarian disease and normal subjects, respectively. For androstenedione the mean percent decreases were only 7% and 20%, respectively. The diurnal variation of all steroids disappeared with dexamethasone. These results support the concept that in patients with polycystic ovarian disease the majority of delta 5-androgens is adrenal while the preponderance of elevated testosterone and androstenedione is ovarian in origin. These results do not support the use of long term dexamethasone as an effective agent in suppressing the elevated levels of testosterone and androstenedione in patients with this disease.

Adult↗
PubMed1981

Reduced sex hormone binding globulin and derived free testosterone levels in women with severe acne.

Reduced circulating sex hormone binding globulin (SHBG) levels were found in 54% of a group of women with moderate to severe acne and in 60% of another group of twenty-three women who had acne complicated by hirsutism and/or irregular menstrual cycles. The concentrations of SHBG for the women with acne alone (mean 48 +/- 24 nmol/l) and for those with acne and hirsutes (mean 39 +/- 18 nmol/l) were compared with the SHBG concentrations of fifteen unaffected women with normal menstrual cycles (mean 70 +/- 19 nmol/l). The differences in mean SHBG values for both groups of women with acne were significant (P less than 0.001) on comparison with the mean for the unaffected women. Twenty-nine per cent of the women with acne had elevated testosterone values (mean testosterone concentration for the group 1.5 +/- 0.3 nmol/l) and 41% had elevated 'derived' free testosterone levels (mean 21 +/- 6 pmol/l). Of the women with acne and hirsutes 65% had elevated plasma testosterone levels (mean 2.1 +/- 0.6 nmol/l) and 89% had elevated free testosterone concentrations (mean 31 +/- 10 pmol/l). The mean values for testosterone and free testosterone in the plasma of unaffected women (mean testosterone concentration 1.1 +/- 0.3 nmol/l and free testosterone 13 +/- 4 pmol/l) were significantly lower than in women with acne alone (P less than 0.01 and P less than 0.001) and in women with acne and hirsutism (P less than 0.001). This study indicates that a deficiency in SHBG and an elevation in 'derived' free testosterone is a frequent finding in women with severe acne and may be a significant factor in the aetiology and/or perpetuation of this condition.

Acne Vulgaris↗
PubMed1978

Prolactin and luteal insufficiency.

The relationship between mid-luteal plasma levels of progesterone and prolactin was studied in 75 women with regular menstrual cycles. Eighteen women had normal prolactin (mean 260 +/- 51.7 mU/l) and normal progesterone levels (mean 67 +/- 21.3 nmol/l). Thirty-nine women had elevated prolactin levels (mean 850 +/- 503 mU/l): progesterone levels were normal in all cases (mean 61 +/- 22.3 nmol/l). Eighteen women had evidence of luteal deficiency (mean progesterone 15.3 +/- 7.7 nmol/l); prolactin levels were normal in all cases (mean 243 +/- 106 mU/l). There was no correlation between plasma prolactin and progesterone levels.

Adult↗
PubMed1977

The effect of dopamine infusion on insulin and glucagon secretion in man.

The effect of dopamine on the release of insulin and glucagon was investigated in eight adult subjects. Dopamine infused iv at a rate of 4 mug/kg/min X 2 hr, unaccompanied by cardiovascular changes, induced a prompt and significant increase in plasma insulin and glucagon and in plasma glucose levels. These findings suggest that dopamine may stimulate both alpha and beta cells.

Adult↗
PubMed1977

The inhibitory effect of dopamine agonists on LH release in women.

Our demonstration of an inhibitory effect of dopamine on LH release prompted us to examine whether a similar action exists for dopamine agonists, such as L-dopa and 2-bromo-alpha-ergocryptine (CB-154). Following the administration of L-dopa (0.5 g, orally) to 6 normal women in the early follicular phase, a significant fall in mean LH levels after 1 h which lasted for 5 h was observed (P less than 0.00005). This was followed by a significant rebound above basal levels between the 7th and 10th h (P less than 0.00005). The expected fall in mean PRL levels which lasted for 4 h (P less than 0.00001) was followed by a significant rebound above basal levels after the 6th h (P less than 0.00001)). There was no significant change in mean FSH levels. Following the administration of CB-154 (2.5 mg. orally) to 6 women with hyperprolactinemic amenorrhea, there was also a significant fall in LH levels (P less than 0.00001) and in FSH levels (P less than 0.00001) from 5 h until the study ended at 10 h. The anticipated PRL suppression was also observed and persisted for the duration of the 10 h study. The demonstration of an inhibitory effect of L-dopa and CB-154 on LH release adds further support to the role of dopaminergic control of pituitary LH secretion.

Amenorrhea↗
PubMed1976

Effects of dopamine infusion on pituitary hormone secretion in humans.

Dopamine, infused at a rate of 4 mug/kg/min for 3-4 h unaccompanied by any significant changes in cardiovascular dynamics, induced a prompt and sustained suppression of circulating prolactin (PRL) levels in normal men and women as well as in patients with hyperprolactinemia. At the discontinuation of the infusion, there was a marked rebound in PRL levels in normal subjects and a rapid return to basal levels in hyperprolactinemic patients. Dopamine infusion also induced a significant fall in LH levels in the normal subjects with a marked rebound in LH levels following the infusion. No significant changes in GH, TSH, and FSH levels were observed. These data indicate that in man a dopaminergic mechanism ixists in the regulation of PRL secretion and that dopamine also exerts an inhibitory effect of LH release.

Dopamine↗