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)

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.

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)

Prolactin and pituitary-gonadal function in cigarette smoking infertile patients

Serum prolactin (PRL) was significantly lower in smokers, compared with non-smokers in 233 males and 250 females referred to our infertility clinics. In subjects smoking 10 cigarettes or more per day, the mean serum PRL was 22% and 20% lower in men and women, respectively. In cigarette smoking men serum testosterone was significantly higher and semen volume lower, while neither serum luteinizing hormone (LH) or follicle stimulating hormone (FSH), sperm density, motility of morphology differed between smokers and non-smokers. It is possible that the higher serum testosterone levels in smokers are due to their lower bodyweight, and that the lower semen volume may be due to an effect of nicotine on the contractility of the deferental ducts. Cigarette smoking may increase central dopaminergic tonus and reduce PRL levels, but it is unknown whether or not this is of biological significance in relation to reproductive function.

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.

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.

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.

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.

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.

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.

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.

Suppressed prolactin but normal neurophysin levels in cigarette smoking breast-feeding women

The hormonal responses to breast-feeding were studied during the first 3 post-partum weeks in ten women smoking more than fifteen cigarettes/day and in a control group. Basal PRL levels were significantly lower in smokers compared with non-smokers, but suckling induced acute increments in serum PRL and oxytocin-linked neurophysin, which were not influenced by smoking. The lactational pattern was normal, but smokers weaned their babies significantly earlier compared with non-smokers. Heavy cigarette smoking women have lower basal PRL levels and this may shorten the period of lactation.

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.

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.

Prl, TSH, GH and LH responses to metoclopramide and breast-feeding in normal and hyperprolactinaemic women

In order to evaluate whether hyperprolactinaemic patients have an increased or decreased central dopaminergic tonus, we compared the serum Prl, TSH, GH and LH responses to metoclopramide (10 mg iv) and to breast-feeding in normal women (n = 8) and hyperprolactinemic patients (n = 8). Prl increments to metoclopramide were significantly (P less than 0.05) impaired in hyperprolactinaemic patients. Serum TSH increased significantly after metoclopramide both in normal and hyperprolactinaemic patients (P less than 0.025), but no significant differences were found between the two groups regarding TSH, GH or LH levels. Hyperprolactinaemic patients had no acute response to suckling while significant increments of Prl and GH (P less than 0.025) occurred in normal women. Out data indicate that the central dopaminergic tonus was not altered in hyperprolactinaemic patients, but showed regulatory dysfunction of both Prl and GH. The concept of a dopaminergic inhibition of TSH secretion was confirmed.

Effect of metoclopramide induced hyperprolactinaemia on the gonadotrophic response to oestradiol and LRH

The effect of oral metoclopramide 10 mg three times daily during the follicular and periovulatory period on Prl, LH, FSH, oestradiol and progesterone was determined in 6 regularly menstruating women. During a control cycle and a treatment cycle the gonadotrophic response was measured after 1 mg oestradiol benzoate given im on the 8th day and after LRH 25 μg iv on the 8th and 11th day of the menstrual cycle. Prl, LH and FSH were also measured in 7 post-menopausal women either during short-term or long-term treatment with metoclopramide. Compared to a control cycle metoclopramide significantly (P < 0.01) increased serum Prl, but a sustained hyperprolactinaemia was not obtained in 2 women. Treatment significantly (P < 0.02) increased the LH and FSH responses to LRH and augmented the negative feedback of oestradiol on both LH and FSH (P < 0.05). A major gonadotrophin surge occurred in those 2 women where a sustained hyperprolactinaemia was not achieved. Oestradiol benzoate caused a significant increase of the LH (P < 0.01) and FSH (P < 0.05) responses to LRH after 72 h during the control cycle, but failed to increase either LH or FSH responses significantly during treatment. Short-term hyperprolactinaemia in post-menopausal women was not associated with any consistent alteration in either LH or FSH levels or pulsatility, but chronic treatment resulted in a significant reduction in serum FSH (P < 0.02), without any alteration in LH levels or pulsatility. LH and FSH responses to LRH increased in all. There was no effect on serum DHAs, urinary androgens or follicular phase serum progesterone levels.

These data show that moderate drug induced moderate hyperprolactinaemia is associated with an increased responsiveness of both LH and FSH to LRH, and has a more pronounced effect on the negative feedback compared to the positive feedback of oestradiol on gonadotrophin secretion. It is suggested that hypersecretion of Prl impairs periodic LH release, mainly through an altered feedback mechanism, but also has a direct inhibitory effect on FSH secretion.

Sex hormone levels and intestinal absorption of estradiol and D-norgestrel in women following bypass surgery for morbid obesity

A report of reduced serum levels of progestins, following oral administration after jejunoileal bypass, promoted the present investigation of the absorption of D-norgestrel and estradiol following different types of intestinal bypass surgery for morbid obesity. A group of non-operated obese patients served as control. Apart from significantly higher gonadotrophin levels, which could be attributed to periovulatory sampling in the non-operated group, there was no significant differences in basal levels of estradiol, estrone, conjugated estrone, androstendione, testosterone, and progesterone. The operation did not influence the pattern of the menstrual cycle. Following a single oral dose of 4 mg micronized estradiol and 125 microgram D-norgestrel, serum levels of estradiol and estrone were equal in the three groups. serum D-norgestrel was equal in the two operated groups, but was significantly higher in the bypass group with 1:3 jejunoileal ratio, compared with the non-operated group. Further, a significant negative correlation between peak levels and weight was found. It is suggested that one year following bypass surgery, obesity - but not intestinal bypass - might be associated with reduced serum levels of exogenous sex steroids following oral administration.

Serum prolactin and oestradiol levels in women with cyclical mastalgia

Basal serum prolactin and serum oestradiol-17-beta concentrations were measured four times during one menstrual cycle in 20 women with severe cyclical mastalgia and normal to slightly fibroadenotic breasts. A group of 10 normal women who had never experienced mastalgia served as controls. Basal serum prolactin was significantly elevated in patients compared to normals, although within the normal range. Serum oestradiol concentrations did not differ in the two groups and were also within the normal range. A significant positive correlation between oestradiol and prolactin was found in patients and normals, but with larger prolactin levels in patients. The results point towards a prolactin secretory hypersensitivity for oestradiol in patients with cyclical mastalgia. Prolactin is considered a central factor in the eliciting of cyclical mastalgia.

Abnormal prolactin levels and pituitary-gonadal axis in the puerperium

To investigate the influence of breast-feeding and prolactin secretion on the pituitary-gonadal function, 3 different groups of patients were studied during the first 8 weeks of the puerperium. Group A comprised patients with hyperprolactinemia and secondary amenorrhea who conceived while on a regimen of bromocriptine. Group B was composed of normal lactating women. Group C comprised nonlactating women treated with bromocriptine. Group A patients had a normal decline in serum prolactin levels during the early postpartum period, but serum prolactin remained completely unaltered after clearance of placental estradiol. In group B suckling increased serum prolactin and suppressed luteinizing hormone. This pattern was not seen in group A. Group C patients had a rapid postpartum normalization of the pituitary-gonadal axis. The results indicate that in relation to lactation the pituitary function is rather autonomous in hyperprolactinemic patients.

Cholesterol saturation of bile after jejunoileal bypass increases more with a 1:3 than with a 3:1 jejunoileal ratio

Previous suggested, surprisingly, that after jejunoileal bypass surgery the lithogenicity of the bile, assessed by its cholesterol saturation and rate of gallstone formation, increases more with a 1:3 than with a 3:1 jejunoileal ratio of the functioning segment. The present study re-evaluates this by examining fasting bile samples drawn from duodenum after cholecystokinin stimulation in 34 obese patients without gallstones, who either were waiting for or had had bypass surgery, with a 1:3 or 3:1 jejunoileal ratio, 3,9, or 15 months earlier. In all groups, the cholesterol content exceeded the solubilizing capacity of the bile as determined on the basis of total lipid concentration and content of phospholipid relative to bile acids. The cholesterol supersaturation increased with bypass surgery as such, increased more with a 1:3 than with a 3:1 jejunoileal ratio, decreased with time after surgery, and reached the preoperative level at 15 months. Assuming a total lipid concentration of 10 g/dl in the bile did not change this pattern. Our results indicate that during the period of weight loss after bypass surgery the lithogenicity of gallbladder bile increases more with a 1:3 than with a 3:1 jejunoileal ratio.