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Biomedical subjects

A N Andersen

Publications and source records attributed to A N Andersen.

At least 73 records · Page 4Linked to original sources
PubMed1986

Increased dopaminergic activity inhibits basal and metoclopramide-stimulated prolactin and thyrotropin secretion.

The influence of physiological to pharmacological doses of dopamine (DA) on basal and metoclopramide (MTC)-stimulated PRL and TSH secretion was studied in 11 regularly menstruating women between days 3 and 8 of the cycle. In groups of 6, the women received 5-h infusions of either 5% glucose or DA in a solution of 5% glucose at a rate of 12-16 ml/h, adjusted according to weight. Infusion rates of DA were 0.04 microgram/kg . min (low), 0.4 microgram/kg . min (medium), and 4.0 micrograms/kg . min (high). After 3 h of infusion, 10 mg MTC were given iv. Blood samples were collected every 15 min from 1 h before to 2 h after the infusion, for a total of 8 h, for measurements of PRL and TSH. The mean serum PRL concentrations declined significantly (P less than 0.05) during DA infusions to nadir values of 62 +/- 5% (+/- SEM; low), 43 +/- 3% (medium), and 43 +/- 6% (high) of the basal levels, whereas basal TSH levels declined significantly, to 64 +/- 5% of basal levels (P less than 0.05), during both the medium and high dose DA infusions. On paired comparisons, the hormone responses to MTC were lower (P less than 0.05) during the infusion of high dose DA (PRL, 2286 +/- 495% vs. 891 +/- 328%; TSH, 100 +/- 43% vs. 60 +/- 15%), but were not changed when MTC was given during the low and medium doses of DA. A rebound phenomenon was found for PRL (P less than 0.05) after the medium and high doses of DA and for TSH (P less than 0.05) after the high dose. These results indicate that doses of DA considered physiological inhibit PRL and TSH secretion and larger doses inhibit their responses to the DA antagonist MTC.

Adult↗
PubMed1986

Prolonged dopamine receptor blockade in normoprolactinemic amenorrhea: a double-blind placebo study.

Patients with functional amenorrhea may have a raised central dopaminergic activity, leading to inhibition of pituitary-ovarian function. In a double-blind placebo trial, ten patients with amenorrhea received metoclopramide (MTC) orally in daily doses from 20 to 7.5 mg in a sequential form for 10 weeks. Six patients received placebo. Serum levels for luteinizing hormone (P less than 0.02), follicle-stimulating hormone (P less than 0.05), and prolactin (P less than 0.001) increased significantly during MTC administration, and no (P greater than 0.05) hormonal changes occurred in the placebo group. Six patients observed vaginal bleedings during MTC administration but without postovulatory progesterone levels. Dopamine receptor blockade may activate the hypothalamic-pituitary axis of amenorrheic patients, although an ovulatory response is not achieved.

Adult↗
PubMed1986

Prolactin and glucose tolerance in normal and gestational diabetic pregnancy.

The relationship between the deterioration of glucose tolerance and plasma prolactin (PRL) levels was investigated in 15 normal pregnant women and in 15 women with gestational diabetes mellitus. Oral glucose tolerance tests were performed in late pregnancy and postpartum, and the insulin, glucagon, and PRL responses were measured. In late pregnancy the gestational diabetics revealed significantly elevated fasting glucose levels compared with the normal pregnant women and after the glucose challenge their insulin responses were significantly diminished and the suppression of glucagon less pronounced. These differences in glucose metabolism were markedly reduced early postpartum. There was no difference in basal PRL concentrations between the two groups neither in pregnancy nor postpartum. The PRL levels were not altered during the oral glucose tolerance tests and no correlation between the deterioration of glucose tolerance and the PRL concentrations could be demonstrated in either group. These results indicate that abnormal PRL levels are not of pathophysiologic importance for the development of gestational diabetes mellitus.

Adolescent↗
PubMed1985

Gonadotropin secretion before and during acute and chronic dopamine-receptor blockade in insulin-dependent diabetic patients with amenorrhea.

The dopaminergic influence on luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin (PRL) was studied in 12 diabetic patients with amenorrhea (DMAM) and in 10 normal menstruating diabetic patients (DM). DMAM patients had a reduction in LH pulsatility (P less than 0.05) and basal LH levels (P less than 0.02), compared with DM patients, whereas they had an LH and FSH response to intravenous metoclopramide (MTC) at 30, 45, and 60 minutes and at 30 minutes, respectively (P less than 0.05). Basal (P less than 0.05) and MTC-stimulated (P less than 0.05) PRL levels were lower in DMAM than in DM patients. Serum PRL and FSH increased significantly (P less than 0.02) in six DMAM patients during 10 weeks of oral MTC administration, whereas no significant (P greater than 0.05) alterations occurred in serum LH and estradiol levels. These data point toward increased dopaminergic activity in DMAM patients.

Adolescent↗
PubMed1985

Abnormal conjugated dopamine levels in patients with normoprolactinaemic amenorrhoea and in insulin-dependent diabetic patients.

We determined the circulating dopamine levels in 17 patients with insulin-dependent diabetes mellitus (IDDM), of whom eight had amenorrhoea (DM-AM) and nine were normally menstruating (DM). Seven non-diabetic women with normoprolactinaemic, normogonadotrophic secondary amenorrhoea (AM) and nine normally menstruating women (controls) were studied. In all subjects basal blood concentrations of free dopamine (f-DA), conjugated dopamine (c-DA), epinephrine (E), norepinephrine (NE), prolactin (PRL), luteinizing hormone (LH), thyroid-stimulating hormone (TSH) and oestradiol-17 beta were determined and all subjects, except for three AM patients, had a Metoclopramide test performed for measurements of f-DA, c-DA, PRL, LH and TSH. Plasma c-DA was significantly (p less than 0.05) increased in patients with amenorrhoea compared to the respective control groups. In diabetic patients c-DA levels were significantly (p less than 0.05) lower compared to controls. The ratio between basal f-DA and c-DA concentrations was significantly (p less than 0.01) higher in diabetic patients compared with non-diabetic patients. After Metoclopramide stimulation DM-AM patients showed a significant (p less than 0.05) rise in c-DA, whereas this was not seen in other groups. DM-AM patients had significantly (p less than 0.05) lower basal PRL and LH levels than DM patients and controls. In addition DM-AM patients had a significantly (p less than 0.05) lower PRL response to Metoclopramide compared with DM patients. There were no significant correlations between catecholamines and basal as well as Metoclopramide stimulated pituitary hormones. This study suggests that the abnormal pituitary hormone secretion in patients with amenorrhoea may in part be caused by an increased dopaminergic activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Evidence of altered dopaminergic modulation of Prl, LH, FSH, GH and TSH secretion during chronic partial dopamine receptor blockade in normal women.

In order to study the influence of chronic, partial dopaminergic blockade on pituitary secretion of Prl, TSH, GH, LH and FSH, 8 normally menstruating women were given metoclopramide (MTC, Primperan ) 7.5 mg daily for 4 weeks. Based on weekly measurements of progesterone, all cycles were ovulatory. Prior to and after 4 weeks of drug administration serial measurements of basal hormone levels as well as the acute alterations after 10 mg of MTC iv were assessed during the early follicular phase. Chronic MTC administration significantly increased serum Prl (P less than 0.02), reduced basal levels of LH (P less than 0.02), whereas basal serum concentrations of TSH, GH and FSH were not changed. Before chronic administration iv MTC evoked significant increments in serum Prl (P less than 0.001), TSH (P less than 0.001) and GH (P less than 0.005). The acute TSH increments were significantly (P less than 0.02) diminished after 4 weeks of treatment. The influence of chronic MTC administration on serum LH and TSH levels may be the result of a competitive effect of a stimulatory influence of the dopamine receptor blocker and an opposing inhibitory influence of an increased hypothalamic dopamine activity, evoked by the MTC induced hyperprolactinaemia. Our data favour that the latter mechanism is dominating in normal women, during chronic administration of a low dose of MTC.

Adult↗
PubMed1984

Evidence of altered dopaminergic modulation of Prl, LH and TSH secretion in patients with normoprolactinaemic amenorrhoea.

Basal plasma concentrations of Prl, LH, FSH, GH, TSH, T3, T4, resin T3 uptake ( RT3U ), and oestradiol as well as hormone responses to iv metoclopramide (MTC) were investigated in 16 consecutive patients with normoprolactinaemic, normogonadotrophic amenorrhoea. The control group consisted of 17 normal menstruating women between day 3 and 6 of the menstrual cycle. The mean age of the amenorrhoeic patients was 24.0 years (range 19 to 34) and the mean duration of amenorrhoea was 31 months (range 12 to 60). Amenorrhoeic patients had significantly (P less than 0.05) lower basal levels of LH, oestradiol and RT3U , whereas other hormone levels were similar in the two groups. Plasma Prl and TSH concentrations rose significantly (P less than 0.05) after the administration of MTC in the two groups. A significant positive correlation (r = 0.69 P less than 0.01) was found between the TSH response to MTC and basal TSH levels in controls, but not in amenorrhoeic patients. Plasma LH levels increased significantly (P less than 0.05) in amenorrhoeic patients, but not in controls. The Prl and TSH responses to MTC were significantly (P less than 0.001) lower in amenorrhoeic patients than in normal women. In amenorrhoeic patients none of the hormonal parameters correlated significantly (P greater than 0.05) with the percentage of ideal body weight. It is concluded that the hormonal changes in amenorrhoeic patients may in part be caused by a raised dopaminergic activity leading to a depression of central ovulatory mechanisms.

Adult↗
PubMed1984

Possible altered dopaminergic modulation of pituitary function in normal-menstruating women with insulin dependent diabetes mellitus (IDDM).

In order to assess whether a possible altered dopamine activity in normal-menstruating diabetic patients may influence the pituitary hormone secretion we have measured the basal serum concentrations of Prl, LH and FSH in 28 patients with insulin dependent diabetes mellitus (IDDM) and in 55 normal-menstruating women at day 3 to 6 of the menstrual cycle. In addition basal levels of oestradiol-17 beta, TSH, thyroxine (T4), triiodothyronine (T3) and resin-T3 uptake (RT3U) were determined in 17 patients with IDDM and in 17 controls. The responses of FSH, LH, Prl, GH and TSH to metoclopramide (MTC) administration (10 mg iv) were studied in 17 patients and 17 controls. In 10 patients with IDDM and 8 controls the short-term variations in pituitary hormones and blood glucose concentration were evaluated. Patients with IDDM had significantly lower basal levels of Prl (P less than 0.01) and TSH (P less than 0.05) and significantly (P less than 0.05) higher basal levels of GH than normal women. No significant (P greater than 0.05) differences were found regarding basal serum concentrations of FSH, LH, oestradiol, T4, T3 and RT3U. During the 3 h period the mean coefficient of variation of Prl, FSH, LH and GH was not significantly (P greater than 0.05) different between diabetic patients and controls. Both groups responded significantly (P less than 0.01) in Prl and TSH to MTC but the TSH response was significantly (P less than 0.05) lower in patients with IDDM. The Prl response to MTC was not significantly (P greater than 0.05) different within the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Preserved prolactin fluctuations and response to metoclopramide in ovulatory, infertile, hyperprolactinemic women.

The study included 18 infertile, hyperprolactinemic women with preserved menstrual cycles. Among 13 women with consistently elevated prolactin (PRL) levels, 6 had either anovulatory cycles or luteal insufficiency, whereas 7 had apparently normal ovulatory cycles. Comparisons of these two groups showed that basal levels were similar but the PRL response to metoclopramide (MTC) and the day-to-day fluctuations were significantly lower in the group with altered ovulatory function. In this group the PRL response to MTC was significantly greater than in control patients with hyperprolactinemic amenorrhea (n = 12), but lower than in normal women (n = 10). The PRL response to MTC in hyperprolactinemic women with normal ovulatory function did not differ significantly from that of normal women, irrespective of whether hyperprolactinemia was sustained (n = 7) or intermittent (n = 5). The study indicates that the degree of autonomy of PRL secretion reflected by both the fluctuations in basal levels and the response to a dopamine antagonist, may be used to evaluate whether or not slightly elevated PRL levels are of clinical significance in relation to fertility.

Adult↗
PubMed1984

Normal and abnormal prolactin levels during human pregnancy. Lack of influence on fetoplacental endocrine function.

Serial measurements of serum prolactin (PRL), chorionic gonadotropin (hCG), estradiol and progesterone were performed during 16 normal pregnancies. The same hormone analyses were performed in a woman with the galactorrhea-amenorrhea syndrome and a pituitary adenoma during two pregnancies, with and without continued treatment with bromocriptine throughout gestation. The study indicates that marked differences in circulating PRL levels do not influence the fetoplacental hormone levels. Furthermore, tumor expansion may possibly be prevented and successful breast-feeding can be achieved after treatment with bromocriptine throughout gestation.

Adenoma↗
PubMed1984

Low maternal but normal fetal prolactin levels in cigarette smoking pregnant women.

In the 36th week of pregnancy, levels of serum prolactin (PRL) (p less than 0.01) and estriol (p less than 0.05) were significantly lower in 101 consecutive women smoking 10 cigarettes or more per day, compared with a control group of 104 non-smoking pregnant women. Cord serum PRL was not related to maternal smoking habits, whereas estriol was significantly (p less than 0.05) lower in the infants of smokers, compared with the control group. The lower PRL levels in cigarette-smoking pregnant women may be due either to a direct effect of nicotine or secondary to lower estrogen levels, and the finding may be of clinical importance in relation to lactation.

Adolescent↗
PubMed1983

Gonadotropin responses to gonadotropin-releasing hormone and prolactin responses to thyrotropin-releasing hormone and metoclopramide in women with amenorrhea and insulin-treated diabetes mellitus.

Gonadotropin responses to GnRH and PRL responses to TRH and metoclopramide (MTC) were investigated in nine consecutive women with amenorrhea and insulin-treated diabetes mellitus. Nine normal menstruating diabetic women, 12 normal women in the early follicular phase, and nine consecutive nondiabetic women with functional amenorrhea served as controls. No significant differences were found in relation to diabetes regulation within the two diabetic groups. Amenorrheic patients with diabetes mellitus had significantly lower basal PRL levels than normal women and estradiol levels compared to the other groups. Basal plasma LH concentrations were significantly lower in women with amenorrhea and diabetes mellitus than in nondiabetics with amenorrhea, whereas plasma FSH levels were similar in all groups. The LH response to GnRH was significantly lower in amenorrheic patients with diabetes mellitus than in normal women, and a significant correlation (r = 0.81, P less than 0.01) was found between the LH response to GnRH and the basal estradiol level in these women. The FSH response to GnRH and the PRL response to TRH were similar in all groups. Amenorrheic diabetics had significantly lower PRL responses to MTC compared to other groups, and nondiabetics with amenorrhea had significantly lower PRL response than normal women. It is concluded that diabetic patients with functional amenorrhea have low basal and MTC-stimulated PRL levels, low basal LH levels, and decreased LH response to GnRH despite low estrogen levels. These hormonal changes may in part be caused by a raised central dopaminergic activity leading to a depression of pituitary ovulatory mechanisms.

Adult↗
PubMed1983

The possible prognostic value of serum prolactin increment during pregnancy in hyperprolactinaemic patients.

In 15 hyperprolactinaemic, infertile patients achieving 17 bromocriptine-induced pregnancies, the presence or absence of prolactin (Prl) increment in the 3rd trimester of pregnancy was correlated to the basal Prl levels before treatment and after pregnancy. The hyperprolactinaemic patients revealed a marked heterogeneity in the Prl increment compared to normal women. Five patients showed a pronounced increase in serum Prl during gestation, whereas Prl levels were unaltered or decreased slightly in 10 patients. In the latter group of patients serum Prl was significantly (P less than 0.01) lower after pregnancy than before treatment. Our study indicates that some hyperprolactinaemic patients may benefit from a pregnancy, and that these patients probably can be identified, as they do not show any significant changes in Prl levels during pregnancy.

Adenoma↗
PubMed1982

Influence of breast-feeding pattern on pituitary-ovarian axis of women in an industrialized community.

A longitudinal study of 48 postpartum women showed that during the first 6 months the daily frequency of infant feedings remained between six and seven. The lower threshold of the ratio breast-feedings/supplementary feedings that sustained both hyperprolactinemia and anovulation was 4.5/1. The duration and the 24-hour distribution, but not the intensity, of breast-feedings were significantly altered during prolonged lactation and when supplementary feeding was used. However, neither differences in the levels of prolactin (PRL) no gonadal status could be correlated with qualitative differences in the breast-feeding pattern. Postpartum maternal body weight was not related to serum PRL, gonadotropins, or resumption of ovulation, but mothers who smoked cigarettes had significantly lower serum levels of PRL during the third and fourth months, and weaned their babies earlier, than did mothers who were nonsmokers. Our data showed that minor quantitative differences in the feeding pattern have a significant impact on the pituitary-gonadal axis, and that the decline in the levels of PRL during continued lactation is due mainly to a decreased frequency of breast-feeding but may be due also to a shorter duration and more heterogeneous 24-hour distribution of nursings but not to a reduced intensity of sucking.

Adult↗
PubMed1982

Excretion of methimazole in human milk.

It is universally stated that antithyroid drugs are concentrated in human milk and are thus contraindicated during breast-feeding. We recently showed, however, that propylthiouracil (PTU) was not concentrated in milk and a study has now been made of the excretion of another widely used antithyroid drug carbimazole (CMI) in human milk. Methimazole (MMI) in blood and milk from five lactating women was measured after oral administration of CMI 40 mg, which is rapidly and completely transformed to the active antithyroid compound MMI. One hour after CMI, the mean serum-MMI reached 253 microgram/I and the mean concentration of MMI in milk reached 182 microgram/I. MMI was found to be unionized and not to be protein bound in serum, and it occurred in milk in the same concentration as the serum; the mean milk/serum ratio was 0.98. The mean total amount of MMI excreted in milk over 8 h was 34 microgram (SEM +/- 5, n = 5), i.e. 0.14% of the dose administered.

Administration, Oral↗