Determination Of Serum Prolactin Research Articles

Pool vs single sample determination of serum prolactin to explore venipuncture associated stress induced variation

Stress is identified as a cause of transient hyperprolactinemia, whereas venipuncture is considered a source of stress for patient. The aim of this study was to investigate the association of venipuncture-induced stress with elevation of serum prolactin. This was a cross-sectional observational study conducted on a group of 150 outdoor patients visiting a tertiary care hospital. Serial sampling was performed by drawing venous blood at different time intervals (0, 30 and 60 min) by single venipuncture to measure serum prolactin to diagnose stress-induced hyperprolactinemia. The study was conducted in two phases, namely, Phase 1 and Phase 2, at different times. The Phase 1 results were divided into two groups: Group 1 (0 min) and Group 5 (pool prepared from samples collected at 0 + 30 + 60 min). Likewise, the results of Phase 2 were segregated into five groups; Group 1 (0 min), Group 2 (30 min), Group 3 (60 min), Group 4 (average of three groups), and Group 5 (pool from samples collected at 0 + 30 + 60 min). In both Phase 1 and Phase 2 of the study, there was a statistically significant (p = 0.0003 in Phase 1 and p = 0.02 in Phase 2) decrease in the mean prolactin (17.99 ± 24.76 ng/mL in Phase 1 and 19.61 ± 23.42 ng/mL in Phase 2) in the pooled samples (Group 5) in comparison to the mean prolactin (19.67 ± 27.69 ng/mL in Phase 1 and 21.06 ± 25.06 ng/mL in Phase 2) of the serum collected at 0 h (Group 1). There was no significant difference in the mean prolactin measured from the pooled samples and average prolactin calculated after individual testing from each sample collected at 0 h, 30 min and 60 min. Venipuncture-triggered fear and apprehension may result in transient hyperprolactinemia. In comparison to performing multiple testing on the samples collected at different time intervals and determining the mean, measurement of the analyte from the pooled serum is the better alternative as it can conserve both time and resources.

RELATIONSHIP OF SEMINAL FRUCTOSE AND SERUM PROLACTIN LEVELS IN INFERTILE MEN

Objective: Male infertility refers to a male’s inability to cause pregnancy in a fertile female. Infertility is a widespread problem for about one in five infertile couples. Male infertility is usually caused by a problem that affects either sperm production or sperm transport. The aim of the study was to evaluate prolactin levels in the serum and comparing the levels of fructose in the semen of infertile males and normal healthy controls of reproductive age of 20–45 years respectively. Methods: Hemoglobin (Hb) level in the blood of both groups was calculated by Sahli’s method using Sahli’s Hemoglobinometer. The Erythrocyte Sedimentation Rate (ESR) was determined using the modified Westergren’s method and total leukocyte count (TLC) in the blood was determined by microdilution method. Semen analysis was performed by the method specified in the World Health Organization Laboratory Manual. Morphology and motility of sperm and their counts were determined by microscopy. Fructose drop test in semen was estimated colorimetrically by the Semen Fructose Estimation Kit and determination of serum prolactin involved the use of Electrochemiluminescence immunoassay using Cobas e 411 analyzer. Results: Hb in infertile males was less than healthy controls. However, ESR in infertile men was considerably high and TLC, serum prolactin levels did not show much variation in infertile men. Seminal analysis of infertile men revealed high fructose levels and low sperm count with decreased motility. Conclusion: The concentration of seminal fructose in control group is lower than infertile males. High fructose levels in infertile men and less sperm count indicate oligozoospermia.

Effects of a progressive or an abrupt increase of hours of light exposition in fall-winter months in finishing Holstein bulls fed high-concentrate diets

A total of 218 Holstein bulls were used to evaluate the effect of a progressive (Experiment 1; n = 106; 335 ± 4.3 kg of BW, and 243 ± 0.1 d of age) and an abrupt (Experiment 2; n = 105; 352 ± 6.7 kg of BW, and 244 ± 2.6 d of age) increase of daylight hours. In experiment 1, bulls were randomly allocated in 2 treatments according to natural photoperiod (NP) or progressive increase of daylight hours (PP) for 84 d of study. In experiment 2, bulls were randomly allocated in 2 treatments according to natural photoperiod (NP) or abrupt increase of daylight hours (AP) for 70 d of study. A computerized concentrate feeder was used to record daily concentrate intake and eating behavior. Body weight and animal behavior was recorded every 14 d until bulls were transported to the slaughterhouse. Blood samples were collected on d 0, 28, 56, and at the end of the study for serum prolactin determination. At slaughter, hot carcass weight and degree of carcass fatness and conformation were recorded. Data were analyzed using mixed models with treatment, time and its interaction as main effects, and the interaction between treatment and pen and the 3-way interaction between treatment, pen and period as random effects. Progressive or abrupt increase of daylight hours up to 16 h a day did not improve weight gain and did not modify total feed intake. In experiment 1, PP calves increased (P < 0.05) number of meals a day while meal size and meal duration decreased (P < 0.001); PP increased lying and rumination time, reduced number of fights, attempts to mount and mounts (P < 0.05) compared with NP. PP bulls tended (P < 0.10) to have a greater percentage of carcasses classified as poor conformation and low fatness scores than NP bulls. In experiment 2, AP calves had more (P < 0.05) attempts to mount and mounts compared with NP. AP bulls increased (P < 0.05) one meal per day compared with NP bulls. Serum prolactin concentration increased (P < 0.05) in PP and AP compared with NP calves. Carcass conformation and fatness did not differ between AP and NP. Progressive photoperiod modification could be used as a strategy to reduce sexual and aggressive behaviors although carcass quality may be impaired. Caution should be taken with abrupt photoperiod modification as sexual behaviors could increase the risk of carcass bruising impairing carcass quality.

Alcohol Use Disorders Identification Test (AUDIT) scores are elevated in antipsychotic-induced hyperprolactinaemia

Hyperprolactinaemia in antipsychotic treated patients with schizophrenia is a consequence of D2 receptor (DRD2) blockade. Alcohol use disorder is commonly comorbid with schizophrenia and low availability of striatal DRD2 may predispose individuals to alcohol use. In this pilot study we investigated whether hyperprolactinaemia secondary to pharmacological DRD2 blockade was associated with alcohol use disorder in 219 (178 males and 41 females) patients with schizophrenia. Serum prolactin determinations were made in patients diagnosed with schizophrenia and maintained on antipsychotic agents. Clinical assessment included demographics, family history and administration of the AUDIT (Alcohol Use Disorders Identification Test). Higher AUDIT scores were associated with prolactin-raising antipsychotic medication (n=106) compared with prolactin-sparing medication (n=113). Risperidone (n=63) treated patients had higher AUDIT scores and prolactin levels than those on other atypical antipsychotics (n = 113). Across the entire sample, patients with a prolactin greater than 800 mIU/L had higher AUDIT scores and were more likely to exceed the cut-off score for harmful and hazardous alcohol use. These differences were not explained by potential confounds related to clinical features and demographics, comorbidity or medication side-effects. These data suggest that by lowering dosage, or switching to another antipsychotic agent, the risk for alcohol use disorder in those with schizophrenia may be reduced. This hypothesis requires testing using a prospective methodology.

The prolactin responses to active and passive heating in man

The aim of this study was to compare the prolactin and blood pressure responses at identical core temperatures during active and passive heat stresses, using prolactin as an indirect marker of central fatigue. Twelve male subjects cycled to exhaustion at 60% maximal oxygen uptake (VO2peak) in a room maintained at 33 degrees C (active). In a second trial they were passively heated (passive) in a water bath (41.56 +/- 1.65 degrees C) until core temperature was equal to the core temperature observed at exhaustion during the active trial. Blood samples were taken from an indwelling venous cannula for the determination of serum prolactin during active heating and at corresponding core temperatures during passive heating. Core temperature was not significantly different between the two methods of heating and averaged 38.81 +/- 0.53 and 38.82 +/- 0.70 degrees C (data expressed as means +/- s.d.) at exhaustion during active heating and at the end of passive heating, respectively (P > 0.05). Mean arterial blood pressure was significantly lower throughout passive heating (active, 73 +/- 9 mmHg; passive, 62 +/- 12 mmHg; P < 0.01). Despite the significantly reduced blood pressure responses during passive heating, during both forms of heating the prolactin response was the same (active, 14.9 +/- 12.6 ng ml(-1); passive, 13.3 +/- 9.6 ng ml(-1); n.s.). These results suggest that thermoregulatory, i.e. core temperature, and not cardiovascular afferents provide the key stimulus for the release of prolactin, an indirect marker of central fatigue, during exercise in the heat.

Platelet monoamine oxidase B (MAO-B) activity and its relationship to DL-fenfluramine-induced prolactin response in healthy men

Several techniques are used to assess central serotonergic neurotransmission in man, e.g. challenge tests (hormonal and physiological responses to serotonin active drugs), platelet MAO-B activity as well as brain imaging techniques. Little is known about how these tests relate to each other. The aim of the present study was therefore to investigate if platelet MAO-B activity could be related to hormonal and temperature responses to the serotonin active drug DL-fenfluramine in healthy men. Twelve male subjects without any history of psychiatric disorders or drug abuse/dependencies were recruited. Prior to the challenge with 60 mg DL-fenfluramine, which was given orally, blood for determination of platelet MAO-B activity was drawn. Blood samples for determination of serum prolactin and serum cortisol were drawn at baseline and thereafter every hour for the following six hours. In addition, body temperature was measured at the same time-points. Delta-values were calculated as the difference between the baseline values and the highest (prolactin and cortisol) or lowest value (temperature) thereafter. There was a strong positive correlation (r = 0.75, p < 0.02) between platelet MAO-B activity and Delta-prolactin. No correlations were found to Delta-cortisol, Delta-temperature or any of the baseline values. The results support the notion that the peripheral marker platelet MAO-B activity is related to the function of the central serotonergic neurotransmitter system as assessed by the prolactin response to 60 mg DL-fenfluramin.

Photoperiod nonresponsive Siberian hamsters: effect of age on the probability of nonresponsiveness.

Groups from three different breeding lines of Siberian hamsters (UNS = general colony animals, PNRa = selected for photoperiod nonresponsiveness as adults, PNRj = selected for photoperiod nonresponsiveness as juveniles) were exposed to short days at weaning and again as adults (Experiment 1) or only as adults (Experiment 2). The proportion of photoperiod nonresponsive individuals in each line was determined by measuring testis length after 6 weeks of exposure to short days (juveniles) or by paired testis weights after 12 weeks in short photoperiod (adults). Adults were blood sampled on the day of sacrifice (Experiment 1) or on Weeks 3, 4, 5, 6, 8, 10, and 12 (Experiment 2) for determination of serum prolactin (PRL) and follicle-stimulating hormone (FSH) concentrations. Nonresponsive individuals were present in all three lines of hamsters. Furthermore, all three lines of hamsters showed an increase in the proportion of nonresponders with age; some individuals are responsive to short days as juveniles, but become nonresponsive in adulthood. The two PNR lines exhibited a greater proportion of nonresponders at both ages compared to the UNS line, with the PNRj line exhibiting the greatest proportion of nonresponders at each age. During exposure to short days, nonresponders exhibited significantly higher serum PRL and FSH concentrations that did the UNS line; nonresponders also exhibited larger testis size, and fewer animals molted to winter-type pelage. The results indicate that (a) in all three lines, a significantly higher proportion of animals are nonresponsive to short photoperiod as adults than as juveniles; (b) selection for nonresponsiveness as juveniles can produce a line of hamsters that, as adults, are nearly all nonresponsive to short days; and (c) some individuals from each line are responsive to short photoperiod early in life, but become nonresponsive as adults.

Differences in the metoclopramide-induced prolactin release related to age at first full-term pregnancy or nulliparity.

To investigate if an association exists in parous women between metoclopramide-induced prolactin (PRL) release and chronological age at first full-term pregnancy and to compare their response to a group of non-parous women, we studied 139 healthy, non-lactating women, aged 15.8-48.2 years, on days 18-22 of their menstrual cycle (except two post-menopausal women). There were 61 parous women divided according to chronological age at first full-term pregnancy: 22 were aged < or = 20.0 years, 25 were aged 20.1-29.9 years and 14 were aged > 30 years. There were also 50 nulliparous women and 28 women who had experienced only first trimester abortions. Three basal blood samples were obtained before oral metoclopramide (10 mg) was administered; subsequently samples were taken at 60, 90 and 120 min. Duplicate serum PRL determinations were performed by radioimmunoanalysis and the area under the curve (AUC) calculated. In parous women, the PRL AUC was positively correlated with chronological age at first full-term pregnancy (P < 0.0001), and it was lower than in nulliparous women or in women with abortions. These data suggest that in parous women a greater dopaminergic tone may exist compared with non-parous women, which seems to decrease gradually as chronological age at first full-term pregnancy increases.

組換えマウスプロラクチンを用いたエンザイムイムノアッセイの開発

組換えマウスプロラクチンを用いたエンザイムイムノアッセイの開発

Serum prolactin response to thyrotropin-releasing hormone during status epilepticus

Determination of serum prolactin can help distinguish between epileptic and pseudo-epileptic attacks since generalized tonic-clonic and complex partial seizures frequently are accompanied by a transient rise in prolactin. In status epilepticus, however, serum prolactin levels are well within the normal range: cellular depletion due to the prolonged seizure activity has been suggested as a mechanism for this finding. The control of prolactin secretion is complex. Among several possible regulators, inhibitory dopamine and stimulatory thyrotropin-releasing hormone (TRH) may take part in the regulation of prolactin levels in connection with epileptic activity. There may be subpopulations of prolactin-producing cells that react differently in response to various regulators. A dopamine receptor blocker given during status epilepticus brings forth a distinct increase in prolactin levels. In order to add to the understanding of prolactin changes in connection with status epilepticus, we injected TRH i.v. during status epilepticus in seven consecutive patients. All patients had prolactin levels within the normal range (< 25 micrograms/l) before injection of TRH which resulted in at least a two-fold increase in prolactin levels. Our results contradict the hypothesis of cellular depletion of prolactin in connection with status epilepticus. The mechanism behind prolactin values within the normal range after prolonged seizure activity remains unknown.

Serotonin function and depression: neuroendocrine and mood responses to intravenous L-tryptophan in depressed patients and healthy comparison subjects

This study was designed to compare central serotonergic function in depressed patients and healthy comparison subjects by examining neuroendocrine and mood responses to intravenous L-tryptophan. One hundred twenty-six drug-free patients with DSM-III-R major depression (109 unipolar, 17 bipolar; 68 melancholic, 58 nonmelancholic; 28 psychotic, and 98 nonpsychotic patients) and 58 healthy comparison subjects participated. After an overnight fast, subjects received an intravenous infusion of L-tryptophan, 7 g. Blood was obtained for determination of serum prolactin, serum growth hormone (GH), and plasma tryptophan levels. Visual analogue scales were used to assess mood. Prolactin responses were blunted in nonmelancholic and higher in melancholic and psychotic depressed patients, while GH responses were blunted in combined unipolar, nonmelancholic, and nonpsychotic depressed patients. Controlling for baseline biological, clinical, and demographic factors eliminated the higher prolactin response in the melancholic and psychotic patients, attenuated the blunted GH response in the unipolar patients, and revealed a blunted GH response in the melancholic patients. Patients and comparison subjects differed on five of 13 mood responses, primarily because of baseline differences. These findings are consistent with previous studies demonstrating blunted neuroendocrine responses to intravenous L-tryptophan in depression. Restriction of these findings to specific subtypes of depression may reflect a differential role of serotonergic abnormalities in these subtypes.

Cabergoline versus Bromocriptine in Suppression of Lactation after Cesarean Delivery

We evaluated the efficacy of cabergoline, a new ergoline derivative, in blocking puerperal lactation in a group of women delivered by cesarean section. In a single-blind controlled trial 36 women were randomly allocated to treatment with cabergoline 1 mg in a single dose p.o. (n = 18) or bromocriptine 5 mg/day p.o. for 14 days (n = 18). Treatment was started about 50 h after delivery. Clinical assessment of breast signs and determination of serum prolactin were performed just before treatment and at 3, 5, 7 and 14 days. In the cabergoline-treated group milk secretion was inhibited in 17 women (94.4%). Maximum decrease of serum prolactin was -89.7% at 5 days, and the prolactin-lowering effect of cabergoline was still present at 14 days. In the bromocriptine group milk secretion was inhibited in 16 women (88.9%). Maximum prolactin decrease (-86.9%) was reached at 3 days. Persistent side effects were comparable in the two groups. This study demonstrates that a single oral dose of 1 mg cabergoline is as effective in suppressing puerperal lactation as a full treatment with bromocriptine, even in women delivered by cesarean section.

Role of serum prolactin determination in evaluation of impotent patient

Hyperprolactinemia is a recognized cause of impotence. The discovery of elevatedprolactin levels in impotent men is very important since pharmacotherapy in this instance is highly successful. We review our experience with prolactin determinations in impotent men, and a population is defined that may benefit from routine prolactin determination. In our experience, the predominant symptom associated with hyperprolactinemia in men is loss of libido.

Presentation and evaluation of hyperprolactinemia in adolescence: Case reports and suggested clinical guidelines

We describe the presentation, clinical evaluation, and outcome of 3 cases of hyperprolactinemia in adolescent females. Case #1 is a 16 and 4/12-year-old female with secondary amenorrhea. Pregnancy testing had previously been negative with no further evaluation. Bilateral expressible galactorrhea was discovered on physical examination and a serum prolactin was 110.3 ng/ml. The computed tomography (CT) scan was normal and menses resumed with bromocriptine therapy. Case #2 is a 15 and Vi2-year-old female who came for a routine yearly examination. She had no complaint and was menstruating regularly. Specific questioning revealed a history of galactorrhea confirmed by physical examination. A serum prolactin was 47.0 ng/ml. A CT scan showed a pituitary microadenoma. She was treated with bromocriptine. Case #3 is a 16 and 9/12-year-old female who was seen for primary amenorrhea. An evaluation revealed a serum prolactin of 143.0 ng/ml. A CT scan showed a pituitary microadenoma. She was treated with bromocriptine and began to menstruate regularly. For the physician seeing the adolescent female, thorough medical histories must include questions regarding the breast, and evaluation for galactorrhea must be part of every breast examination. The physician also needs to be familiar with the evaluation of amenorrhea and/or galactorrhea and include determination of serum prolactin when indicated. We recommend obtaining a constant enhanced CT scan or magnetic resonance imaging (MRI) of the sella turcica to evaluate any elevation of serum prolactin.

Serum prolactins in the diagnosis of epilepsy

Serum prolactin levels rise after generalized tonic-clonic and partial complex seizures, but not after pseudoepileptic seizures. The criteria for a significant elevation in serum prolactin vary with individual investigators. The prevalence of pseudoseizures in the population studied determines the predictive value of serum prolactin determinations. In populations where most patients have epilepsy, a rise in serum prolactin is highly predictive for true epilepsy, but no increase in serum prolactin is not predictive for pseudoseizures.

Use of sexual history to differentiate organic from psychogenic impotence.

The use of sexual symptomatology to differentiate psychogenic from organogenic impotence was studied. All patients were independently classified based on the evaluation of a minimum of one night of nocturnal penile tumescence recording, a sleep lab technician's rating of penile turgidity of erections, Doppler determination of penile blood flow, determination of serum prolactin and testosterone levels. Three aspects of symptomatology significantly discriminated the criterion groups. The single best predictor was the presence or absence of early morning erections as reported by the patient.

Pituitary transplantation: Part 1. Successful reconstitution of pituitary-dependent hormone levels.

Neonatal or adult pituitary glands were transplanted to the median eminence of adult rats of the same or a histoincompatible inbred strain. The hormonal status of 39 transplanted rats and of control animals was evaluated by serial determination of serum prolactin and thyroxine. Grafts of neonatal tissue to adults of the same strain resulted in normal postoperative hormone levels. This indicates not only that pituitary grafts had survived, but also that the transplants were under hypothalamic control. Grafts of adult tissue were less successful. The prolactin value was lower, but still within the normal range, whereas the thyroxine value was lower than normal, suggesting that viable pituitary tissue had survived but was not under hypothalamic control. Transplantation across a histocompatibility barrier was uniformly unsuccessful. Postoperative prolactin levels were low and thyroxine levels were not significantly different from those in hypophysectomized controls.

Involvement of cholinergic nicotine-like receptors as modulators of amine turnover in various types of hypothalamic dopamine and noradrenaline nerve terminal systems and of prolactin, LH, FSH and TSH secretion in the castrated male rat.

The effects of high repeated subcutaneous doses (4 X 2 mg/kg) of nicotine have been evaluated on dopamine (DA) and noradrenaline (NA) levels and turnover in the long-term castrated male rat using catecholamine (CA) fluorescence histochemistry in combination with quantitative microfluorometry. The CA turnover was evaluated by studying the decline of the CA stores following tyrosine hydroxylase inhibition using alpha-methyltyrosine methyl ester (H 44/68). In the same experiments trunk blood was collected for the determination of serum prolactin, LH, FSH and TSH levels using standard radioimmunoassay procedures. The nicotine treatment produced a significant depletion of CA stores and an increase of CA turnover in DA and NA nerve terminals of the median eminence and in peri- and paraventricular NA systems. These effects were significantly counteracted by pretreatment with mecamylamine. Nicotine significantly reduced serum prolactin and TSH levels, and after H 44/68 it also reduced LH and FSH serum levels. These actions were counteracted by mecamylamine pretreatment, except the effects on serum TSH levels after H 44/68, which were even enhanced by pretreatment with mecamylamine. Overall intraindividual correlations showed a significant correlation between reduced CA turnover in several hypothalamic areas and increased serum LH and FSH levels, increased NA turnover in the paraventricular hypothalamic nucleus and increased serum TSH levels, and reduced DA turnover in the median eminence and increased serum LH levels. It is suggested that in the castrated male rat nicotine can activate cholinergic nicotine-like receptors facilitating DA and NA turnover and release in various hypothalamic CA nerve terminal systems including those inhibiting the secretion of prolactin and LH (DA terminals in medial and lateral palisade zone, respectively) and facilitating secretion of TSH (NA terminals in the parvocellular part of the paraventricular hypothalamic nucleus).

食餌コーン油含量の乳癌発育に及ぼす効果

To ascertain the effect of fat-content in diet on the development of breast cancer, the semisynthetic diets containing corn oil (polyunsaturated fatty acids; more than 80%) in the weight percentages of 0,8 or 40 were prepared and 141 young adult Sprague-Dawley females were used for the following experimental designs. In the first group, the uptake and clearance of labeled DMBA within the mammary fatty pads of 20 rats administered by fat-free and 40%corn oil diets, respectively, at the ages of 45-87 days were observed in 3 days after the intravenous injection of carcinogen. In the second group,90 rats (a-subgroup) were intubated by 10mg of DMBA twice on the ages of 56 and 59 days, and 31 rats (b-subgroup) never received DMBA. The animals of b-subgroup were fed on fat-free,8% corn oil and 40% corn oil diets, respectively, at the ages of 70-100 or -115 days, and they were finally sacrificed either for the determination of serum prolactin and estrogens or for the analysis of fatty acid compositions within the mammary fatty pads. The effective number of rats in a-subgroup were fed on 3kinds of the above-mentioned semisynthetic diets, respectively, at the ages of 90-150 days, and they were applied to the observations on the developments of mammary cancers, endocrinologic states of these cancer-bearers and fatty acid compositions of these mammary tumor phospholipids.In group II a, the averages of caloric intake were 52.4,52.2 and 50.3 Cal/rat/day, respectively, in the fat-free,8% corn oil and 40% corn oil diet groups, and the curves of average body weight were not different from each other diet group. However, both the average number of cancer per a rat (3.2±2.2,6.5±2.5) and average weight of cancer per a rat (654.0±498.7mg,690.5±477.3mg) were much higher in the 8% and 40% corn oil diet groups, wit h compared from the fat-free diet group (1.6±0.9,331.6±226.5mg). These figures were statistically different from each other diet group (p<0.01). The endocrinologic states (serum prolactin, serum estrogens, prolactin/estrogens at the same sexual cycle and weight of the endocrine organs) of the hosts were similar in each diet groups. In the mammary tumor phospholipids, linoleic acid increased and arachidonic acid decreased in the 40% corn oil diet group, in comparison of the fat-free diet group. These deviations were statistically significant (p<0.01). In group 11b, the hormonal balances of animals seemed to be not disturbed by these semisynthetic diets, and linoleic acid within the mammary fatty pads decreased profoundly in the fat-free diet group, where any disorders from essential fatty acid deficiency could not be detected yet. In group II, the uptake and clearance of tritiated DMBA within the mammary fatty pads of the 40% corn oil diet group were not significantly different from those of the other diet groups.In conclusion, the extremely high corn oil diet enhanced prominently the devel opment of DMBA-induced mammary cancers, especially number of cancer per an animal, without any endocrinologic and caloric alterations in these cancer-bearers. Such an enhancement might be introduced by the increased amounts of polyunsaturated fatty acids within the mammary fatty pads of the hosts and by some alterations of fatty acid composition of the tumor phospholipids.

Pituitary Tumors and Hyperprolactinemia

Hyperprolactinemia was demonstrated in eight of nine patients with clinical evidence of pituitary tumors without acromegaly or Cushing syndrome. Hourly sampling for 24 hours disclosed elevation of serum prolactin concentrations, whereas, measurable serum growth hormone levels were found rarely. Although eight of these patients were hypersecreting prolactin, only four of them were lactating. Prolactin secretion was characterized by moderate hourly fluctuations of serum levels and absence or blunting of the normal sleep-related augmentation of secretion. Patients with the highest serum prolactin concentrations tended to have the largest pituitary tumors, as indicated by pneumoencephalography. In two patients followed-up with serum prolactin determinations after treatment, a fall in serum prolactin concentrations correlated with clinical improvement. Future study will hopefully establish the value of serum prolactin determinations in following tumor growth before and after pituitary ablative therapy.