A comparative analysis of tellurite detoxification by members of the genus Shewanella.

The increasing industrial utilization of tellurium has resulted in an important environmental pollution with the soluble, extremely toxic oxyanion tellurite. In this context, the use of microorganisms for detoxifying tellurite or tellurium biorecovery has gained great interest. The ability of different Shewanella strains to reduce tellurite to elemental tellurium was assessed; the results showed that the reduction process is dependent on electron transport and the ∆pH gradient. While S. baltica OS155 showed the highest tellurite resistance, S. putrefaciens was the most efficient in reducing tellurite. Moreover, pH-dependent tellurite transformation was associated with tellurium precipitation as tellurium dioxide. In summary, this work highlights the high tellurite reduction/detoxification ability exhibited by a number of Shewanella species, which could represent the starting point to develop friendly methods for the recovery of elemental tellurium (or tellurium dioxide).

Construction of 6-thioguanine and 6-mercaptopurine carriers based on ßcyclodextrins and gold nanoparticles.

As a novel strategy to overcome some of the therapeutic disadvantages of 6-thioguanine (TG) and 6-mercaptopurine (MP), we propose the inclusion of these drugs in ßcyclodextrin (ßCD) to form the complexes ßCD-TG and ßCD-MP, followed by subsequent interaction with gold nanoparticles (AuNPs), generating the ternary systems: ßCD-TG-AuNPs and ßCD-MP-AuNPs. This modification increased their solubility and improved their stability, betting by a site-specific transport due to their nanometric dimensions, among other advantages. The formation of the complexes was confirmed using powder X-ray diffraction, thermogravimetric analysis and one and two-dimensional NMR. A theoretical study using DFT and molecular modelling was conducted to obtain the more stable tautomeric species of TG and MP in solution and confirm the proposed inclusion geometries. The deposition of AuNPs onto ßCD-TG and ßCD-MP via sputtering was confirmed by UV-vis spectroscopy. Subsequently, the ternary systems were characterized by TEM, FE-SEM and EDX to directly observe the deposited AuNPs and evaluate their sizes, size dispersion, and composition. Finally, the in vitro permeability of the ternary systems was studied using parallel artificial membrane permeability assay (PAMPA).

Alkylglycerols reduce serum complement and plasma vascular endothelial growth factor in obese individuals.

Alkylglycerols (AKGs), isolated or present in shark liver oil have anti-inflammatory properties. Complement 3 (C3) and 4 (C4) participate in lipid metabolism and in obesity, contributing to the metabolic syndrome and to the low-grade inflammation associated with obesity. In a randomized, controlled, crossover study, 26 non-diabetes obese individuals were assigned two preparations with low (LAC, 10 mg AKGs) and high (HAC, 20 mg AKGs) AKG content. Intervention periods were of 3 weeks preceded by 2-week washout periods in which shark liver oil was avoided. Cholesterol, C3, C4, and vascular endothelial growth factor (VEGF) decreased in a linear trend (P < 0.01) from baseline (control) to LAC and HAC. Values after HAC were significantly lower (P < 0.05) versus both baseline and after LAC. No adverse effects were observed or reported. Data from this pilot study open a promising field for the study of the beneficial effects of AKGs on cardiovascular risk factors in obese individuals.

Frequency of luteinizing hormone pulses in cattle influences duration of persistence of dominant ovarian follicles, follicular fluid concentrations of steroids, and activity of insulin-like growth factor binding proteins.

The objectives of the present study were to determine how varying frequency of LH pulses as controlled by varying treatments with progesterone (P4) in cattle would affect: (1) concentration of steroid hormones and activity of insulin-like growth factor binding proteins (IGFBPs) in the ovarian follicular fluid and blood plasma, and (2) duration of persistence of largest ovarian follicles. There were four treatment groups (n=7 per group) and a control group (n=5) of mature, non-lactating beef cows. Treatments were: (1) two progesterone releasing intravaginal devices (PRIDs) for 16 days (2PRID); (2) a half PRID for 16 days (0.5PRID); (3) two PRIDs for 8 days, then a half PRID for 8 days (2-0.5PRID); or (4) a half PRID for 8 days, then two PRIDs for 8 days (0.5-2PRID). Treatment was initiated on the fifth day of the estrous cycle, which was designated as Day 0, and continued for 16 days. All P4-treated females were administered prostaglandin F2alpha on Day 0 and 1 to regress their corpora lutea. Frequency of LH pulses was greater during treatment with the smaller dose of P4 compared with treatment with the larger dose of P4 and the control group. Ovarian follicles were classified into five categories based on ultrasonographic observations: growing (G); atretic (A); growing dominant (GD); growing persistent (GP); or atretic persistent (AP). At ovariectomy on Day 16, the largest and second largest follicles collected were re-classified into five categories based on follicular concentration of steroids. Classification of the largest follicle collected on Day 16 was influenced by treatment (P<0.005), with the 2PRID group having A follicles, the 2-0.5PRID group GP follicles, the 0.5-2PRID group AP follicles, and the 0.5PRID group GD and GP follicles. Concentrations of 17beta-estradiol (E2) were greatest in GD and GP follicles (P<0.05). There was less (P<0.05) activity of IGFBP-2 in GD follicles and less (P<0.05) activity of IGFBP-3 in GD and GP follicles than other follicles. Activity of IGFBP-4 and -5 was greater (P<0.05) in A and AP follicles than G, GD, and GP follicles. Maintenance of a frequent release of LH pulses over a 16-day period did not result in maintenance of persistent follicles throughout this period indicating that duration of dominance of these follicles is finite even when there is frequent release of LH pulses. Follicular atresia is associated with greater activity of IGFBP-2, -4, -5, and greater concentrations of P4 in follicles, whereas growing dominant and persistent follicles contained greater concentrations of E2, androstenedione (A4), and less IGFBP-2 activity than follicles of other classes. Follicle classifications based on ultrasonography or follicular concentration of steroids did differ (P<0.05) for the largest follicles from the 2PRID group. Two follicles in this group appeared as GD follicles by ultrasonography, but these were atretic based on follicular steroid contents. Objective 1 of the present study yielded the conclusion that concentrations of steroid hormones in follicular fluid and blood plasma could be predictably controlled by regulating the frequency of LH pulses with varying doses of P4. Objective 2 yielded the conclusion that maintain frequent release of LH pulses over a 16-day period could not maintain persistent follicles throughout this period, indicating that duration of dominance of these follicles is finite even when there is frequent release of LH pulses. Follicular atresia in the present study was associated with increased follicular fluid activity of IGFBP-2, -4, -5, and P4, whereas growing dominant and persistent follicles contained greater concentrations of E2, A4, and less IGFBP-2 activity than follicles of other classes.

[Second resection in patients with Ta-T1 bladder tumors]. / Segunda resección en pacientes con tumores vesicales Ta-T1.

OBJECTIVES: To study the incidence of "residual/recurrence" tumor after a second bladder resection (2nd TUR). METHODS: 40 patients with new or recurrent superficial bladder tumor underwent repeat transurethral resection within 3 months after the initial resection. 37 patients were staged as Ta-T1. We study the incidence of tumor after the 2nd TUR both macroscopically detected or included in the bladder scar. We also study the influence of possible factors as the time between both resections, stage, grade, number of tumor size, localization in the bladder, primary or recurrent tumor and tumor pattern. RESULTS: After the 2nd TUR we found tumor in 14 of 37 (37.8%) Ta-T1 bladder tumors. Among the 14 tumors, 10 (71.5%) were macroscopically visible tumors and 4 cases the tumor were found after resection of the bladder scar of the first resection. We did not find relation between the presence of tumor in the 2nd TUR and any of the variables. CONCLUSIONS: After a TUR of superficial bladder tumor the complete removal of tumor is not always achieved. The early 3 months cystoscopy may not find residual tumor. Although we have found tumor in 37.8% in the 2a TUR we can not recommend routine 2nd TUR in superficial bladder cancer.

Segunda resección en pacientes con tumores vesicales Ta-T1 / Second TUR in patients with stage Ta-T1 transicional cell carcinoma of the bladder

OBJETIVO: Estudiar la incidencia de tumor "residual/recidivante" tras segunda resección precoz (2ª RTU), y que factores influyen en su hallazgo. MATERIAL Y MÉTODO: Estudio prospectivo de 40 pacientes con neoplasia vesical superficial a los que se les realizó una 2ª RTU precoz. Como posibles factores de riesgo de hallazgo de tumor se estudiaron el intervalo de tiempo entre ambas RTU, el estadio, el grado, el número de implantes tumorales, el tamaño de los implantes, localización dentro de la vejiga, tumor primario o recidivante y el patrón tumoral. RESULTADOS: Al realizar la 2ª RTU se confirmó histológicamente tumor en 14 (37,8 por ciento) de 37 pacientes con tumores Ta-T1 (excluimos aquellos con afectación focal de la muscular): 10 (71,5 por ciento) eran tumores macroscópicamente visibles, en 4 casos (28,5 por ciento) se encontró tumor al biopsiar las áreas de cicatriz/edema de la resección anterior. No encontramos asociación entre la presencia de tumor en la 2ª RTU y ninguna de las variables en estudio. CONCLUSIONES: La erradicación de tumor vesical superficial mediante RTU no se consigue en un elevado porcentaje de pacientes. La cistoscopia a los tres meses no puede excluir tumor residual. Aunque hemos encontrado 37,8 por ciento de tumor en la 2ª RTU, actualmente no podemos recomendarla de forma rutinaria en los tumores vesicales superficiales (AU)

Ultrastructure and motility of the caudal epididymis spermatozoa from the volcano mouse (Neotomodon alstoni alstoni Merriam, 1898).

The volcano mouse Neotomodon alstoni alstoni is a genus endemic to the higher elevations of the Mexican transvolcanic belt. In the present study we examined for the first time the morphological features of the spermatozoa taken from the caudal epididymis of this species by transmission and scanning electron microscopy. Spermatozoan motility was studied in sucrose and bicarbonate solutions; vitality and morphology were observed by light microscopy. Transmission electron microscopy shows that the head of spermatozoon is asymmetric and possesses a large and curved hook. The axoneme of the spermatozoan tail is highly developed at fibers 1, 5, and 6. Absolute and relative measurements of the length of the head, the midpiece, and the rest of the tail were also obtained. N. alstoni alstoni spermatozoa were hyperactive in the presence of 290 mM sucrose and 10 and 20 nM bicarbonate solutions exhibited high motility (180-190 microm/sec), and high flagellum beating frequency (10-12 Hz). In contrast, the spermatozoa in 310 mM sucrose solution showed scarce motility (13.5 +/- 3.8 microm/sec) and low beating frequency (1.5 +/- 0.4 Hz). It is proposed that the volcano mouse spermatozoa possess some features very similar to other mammalian spermatozoa and that bicarbonate triggers caudal epididymal sperm motility of this species. J. Exp. Zool. 287:316-326, 2000.

Nutrición enteral en crisis grave de colitis ulcerosa: efectividad nutricional y tolerancia digestiva / Enteral nutrition in severe ulcerative colitis: safety, tolerance and nutritional efficiency

Backgrounds and aims: Total parenteral nutrition (TPN) has been traditionally used as an adjunctive therapy in severe ulcerative colitis patients. We performed a prospective study to ascertain the safety, nutritional efficiency, tolerance and costs of total enteral nutrition in this situation. Methods: After 48 hours of intensive medical treatment, severe ulcerative colitis patients initiated enteral feeding with a polymeric formula. The formula concentration and volume were increased daily. Results: 17 patients (7 women, 10 men; age 36,8ñ12,8 years) with a mean clinical activity score of 15,6ñ1,5 were included. In 14 patients (82,4percent) enteral nutrition was well tolerated, attaining in 11 of them more than 80percent of the caloric requirements by day 4. In 3 cases we observed vomiting and bloating. Prealbumin levels improved significantly from 11,1ñ3,4 mg/dl to 22,7ñ6,8 mg/dl (p= 0.002) at the end of enteral nutrition (11,8ñ4,7 days). Albumin and other nutritional parameters did not change. Conclusions: Total enteral nutrition could be considered a safe and well tolerated nutritional support in these patients. Although albumin and other nutritional parameters did not change during the study period, the increase in prealbumin levels suggests a favourable anabolic effect of total enteral nutrition

Colitis ulcerosa y embarazo / Evolution of ulcerative colitis in pregnancy

Background: The evolution of ulcerative colitis in pregnancy is far from clear. While some authors state that the disease aggravates during this period, others do not share this opinion. Aim: To assess the evolution of ulcerative colitis in pregnancy. Patients and methods: A paired case-control design was used in which 15 women, with diagnosed ulcerative colitis at the moment of becoming pregnant, were followed for 12 months and the activity of the disease was compared with that of the 12 months preceding the pregnancy. The activity of the disease in the period preceding the pregnancy was gathered retrospectively from the patient's charts. Results: The mean age of the first ulcerative colitis crisis was 24 years. It was moderate in 49 percent and severe in 35 percent of women. During pregnancy 55 percent of women did not have a crisis, compared with 26.7 percent during the period preceding pregnancy (relative risk of not having a crisis during pregnancy of 1.7). During both periods, seven women had digestive complications, whereas extra digestive complications were not observed in 60 percent of patients during pregnancy and 11.8 percent of patients during the preceding period. Perinatal results were similar to those of the general population. Conclusions: In our group of patients the evolution of ulcerative colitis was better during pregnancy, reflected by a lower number of crisis

[Kikuchi-Fujimoto disease associated with acute infection by herpesvirus 6]. / Enfermedad de Kikuchi-Fujimoto asociada a infección aguda por virus herpes 6.

The histiocytic necrotizing lymphadenitis or Kikuchi-Fujimoto disease is a very rare entity in Spain. We present a 34-year-old arabic male admitted to hospital because one-month story of asthenia, anorexia, weight loss, fever and lymphadenopathies in all palpable sites. Analytic studies were all within normal limits except LDH levels and globular sedimentation rate, both raised. After cervical lymph node biopsy performance high grade Non-Hodgkin lymphoma was initially diagnosed. During admission he complained from pain in both shoulders and an erythematous desquamative eruption in trunk appeared. Some days later, a second lymph node biopsy was performed and Kikuchi-Fujimoto disease was diagnosed. Serologic tests for human herpes virus 6 were positive demonstrating active associated infection. He begun treatment with indomethicin, fever and general symptoms disappeared one week later discontinuing treatment. Two months after discharge, all lymphadenopathies had disappeared. A review on epidemiological, clinical, pathological and differential diagnosis issues is made.

[Usefulness of bone marrow examination in patients with advanced HIV infection]. / Utilidad del estudio de médula ósea en pacientes con infección por VIH avanzada.

A bone marrow investigation is a common examination in HIV infected patients for the study of cytopenia, febrile syndromes of unknown origin and extension of neoplastic disorders. A study was made of bone marrow specimens from 35 patients with advanced HIV infection (stage IC or C, CDC, Atlanta) for morphologic and culture investigations (aerobes, anaerobes, fungi, and mycobacteria). In nine patients cytopenia accounted for the investigation of bone marrow specimens (9 aspirates and 3 biopsies); in only two cases did the investigation orientate towards a possible etiology: in the first patient a parvovirus B19 infection and in the second patient a hemophagocytic syndrome. In twenty-five patients the bone marrow specimen was studied because of fever of unknown origin (23 aspirates and 10 biopsies) and only in one case was the identification of Mycobacterium tuberculosis obtained. The other patient was studied for lymphoma staging and aspirate and biopsy examinations were normal. A high percentage of patients had eosinophilia, plasmacytosis, increased iron reserves, fibrosis, and changes consistent with myelodysplasia. In conclusion, in our experience the investigation of bone marrow specimen was of little help to clarify the possible etiology of cytopenia and febrile syndromes of unknown origin in patients with advanced HIV infection.

Effect of posterior pituitary lobectomy on in vivo and in vitro secretion of prolactin in lactating rats.

The effect of removing the posterior and neuro-intermediate lobes (PLX) of the pituitary gland of lactating rats was determined on both suckling-induced release and transformation of prolactin (PRL), and on regionalization of PRL release. Sixteen hours, or 1 or 4 d after either PLX or sham surgery, acute (15-min) suckling was applied. Also, regionalization of PRL release was analyzed by incubating the central and peripheral regions of APs from nonsuckled rats. Plasma PRL was analyzed by radioimmunoanalysis (RIA), whereas anterior pituitary (AP) PRL content and in vitro released PRL were determined by polyacrylamide gel electrophoresis. Plasma PRL increased 25- to 30-fold after suckling in intact and sham, and 10- to 15-fold in 1- and 4-d PLX rats, but no change occurred on either 16-h PLX nonsuckled and suckled rats. Also, PRL transformation occurred in intact, sham, and 4-d PLX suckled rats, but not in 16-h sham, or in 16-h and 1-d PLX suckled rats. Finally, the higher secretion of PRL shown in vitro by the central region of APs from intact and sham was not observed in APs from PLX rats. These results show that PLX transiently depresses the suckling-regulated PRL transformation and release. Likewise, influences from the posterior and/or neuro-intermediate lobes may determine regionalization of PRL release.

Central effects of catecholamines upon mammary contractility in rats are neurally mediated.

We injected, i.e., intracerebroventricularly (ICV) or systematically, small amounts of adrenaline (ADR), noradrenaline (NA), isoproterenol (ISOP) and dopamine (DA) in urethane-anesthetized lactating rats, and determined the effects on isometrically recorded intramammary pressure (IMP) responses to exogenous oxytocin (OXY). While centrally administered ADR, NA and DA provoked increased IMP responses to OXY, the beta-adrenergic agonist ISOP induced the opposite effect. These effects were reversible, dose related and also occurred in hypophysectomized rats. However, when injected systematically, all adrenergic agonists but DA depressed IMP responses to OXY. Further experiments showed that central effects of catecholamines were exerted by regulating ductal tone, through the direct innervation of the mammary glands. Thus, whereas complete blockage of these effects occurred after selective denervation of the mammary glands, increased ductal tone resulted from ICV administration of ISOP. Finally, evidence was also obtained that antagonistic alpha- and beta-adrenergic mechanisms may interact with each other to regulate milk ejection, and with afferent signals from the mammary glands. Thus, beta-adrenergic inhibition upon IMP was counteracted by either NA administration or by activation of ductal mechanoreceptors. Together, these results suggest that regulation of milk ejection may involve neurally mediated influences on mammary contractility. Such actions would interact closely with afferents from the mammary gland influencing ductal tone.

[Hodgkin's disease and HIV: relations between CD4/CD8 rate, histology and stage]. / Enfermedad de Hodgkin y VIH. Relación entre el cociente CD4/CD8, histología y estadio.

Hodgkin's disease (HD) is not currently accepted as an AIDS diagnostic criterion by the Centers for Disease Control (Atlanta), although there are reports on a higher incidence of the disease in HIV infected patients, with the special feature of a marked clinical and histological aggressiveness. A review of the literature was made and a total of 54 cases of HD compiled of patients with HIV infection. The relationships between the absolute counts of CD4 and the CD4/CD8 ratio with histopathology and with the stage at diagnosis was investigated. No significant differences were found between the absolute counts of CD4 and CD4/CD8 ratio with the clinical stage of disease, histopathologic subgroup or presence of B symptoms in HD. Nevertheless, lower CD4 counts were observed in more advanced clinical stages and in patients with B symptoms; the highest CD4/CD8 ratios were observed in patients with more advanced disease. It is hypothesized that immunological disturbances caused by HIV would lead to more aggressive histological lesions and more advanced stages of HD in HIV-positive patients. Thus, the inclusion of HD as a diagnostic criterion of AIDS would be warranted.

Changes in molecular variants during in vitro transformation and release of prolactin by the pituitary gland of the lactating rat.

PRL transformation involves a dopamine (DA)-controlled, thiol-mediated decrease in pituitary PRL detectability that precedes and may determine increased PRL release. The present studies were designed to determine 1) whether structural changes occur to adenohypophyseal (AP) PRL during in vitro transformation and may account for decreased PRL detectability; 2) whether such changes occur within AP PRL granules; 3) the type and proportion of secreted PRL variants; and 4) the influence of DA and/or thiol reducing agents upon AP PRL molecular changes. Quartered APs of 8 h nonsuckled lactating rats, injected or not with [3H]leucine (5 mCi/g body wt, 8 h before death) were incubated for 30-240 min. The effects of DA (50 microM) with or without reduced glutathione (10 mM), and the alkylant N-ethylmaleimide (1 mM) were compared to the changes in PRL molecular variants occurring in control incubated AP fragments. Polyacrylamide gel electrophoresis (PAGE) under native conditions and sodium dodecyl sulfate (SDS)-PAGE under reducing (R) or nonreducing (NR) conditions were used to resolve molecular variants of PRL and [3H]PRL, followed by Western blotting and densitometric/liquid scintillation techniques, respectively. Up to 5 and 10 major forms of immunoreactive PRL were resolved by PAGE and SDS-PAGE, respectively. The spontaneous transformation after 30 min incubation was correlated with a decrease of 23K PRL and 23K [3H]PRL bands and an increase in high mol wt (80 to greater than 100K) PRL forms. These changes were reversible upon reduction of the proteins before electrophoresis or after extraction of preparative gels. DA and N-ethylmaleimide prevented, whereas reduced glutathione induced these changes. Similar changes were observed in isolated granules from nonincubated and incubated pituitary fragments. Secreted PRL was also polymorphic, with a high predominance of 23K PRL and 23K [3H]PRL. In addition, a polymeric PRL variant, which in reducing gels showed an apparent mol wt of 27K, was secreted in high proportion, similar to that of 23K PRL. The nature of this polymeric variant of PRL is unclear at present. Altogether, these results suggest that a dynamic interconversion of PRL molecular variants occur during transformation. The decreased detectability associated with PRL transformation appears to involve the association of 23K PRL molecules into a 80 to greater than 100K disulfide-linked oligomer. This association is reversible upon reduction and takes place within secretory granules. DA appears to inhibit PRL transformation by preventing thiol-disulfide interchange.

Prolactin and propranolol prevent the suckling-induced inhibition of lactation in rabbits.

The normal once-a-day frequency of suckling in the rabbit was increased on day 31 (late lactation) by the addition of two extra sucklings (8 and 16 hr after) the daily suckling. In confirmation of previous data, two additional sucklings significantly decreased milk yield acutely on day 31 in comparison with the average 4-day milk yield before and after day 31. The decrease in milk secretion after the two additional sucklings was prevented by a single injection of 3 mg prolactin (given 24 hr before the two extra sucklings) and/or by injections of the beta-adrenergic-blocking drug, propranolol (100 micrograms/kg b. wt. given 30 min before each additional suckling). Since prolactin secretion is decreased in these species and the mammary gland is less responsive to the hormone during late lactation, the present results suggest that in addition to these factors, suckling-induced activation of sympathetic influences may contribute to the decline in milk production at this stage of lactation. Taken together, these results suggest that suckling may regulate lactation in the rabbit through antagonistic mechanisms at different stages of lactation.

Incidencia de displasia broncopulmonar / Incidence of bronchopulmonary dysplasia

Se determinó retrospectivamente la incidencia de displasia broncopulmonar en el total de recién nacidos sometidos a ventilación artificial en una unidad de neonatología, analizándola según peso al nacer y comparándola con la observada en el subgrupo de recién nacidos ventilados sobrevivientes a los 28 días de edad. Se estudió la posible asociación entre displasia broncopulmonar, enfermedad de membrana hialina, ductus arterioso permeable y rotura alveolar. El número de pacientes ventilados fue 200, de los cuales 9,5 por cento presentaron evidencias de DBP (19/200), falleciendo 1 de ellos (letalidad 5,2 por cento). La incidencia aumentó en forma progresiva en los niños de menor PN, hasta llegar a 37,5 por cento en los de <1.000 g (p <0,001 X*). Al considerar los sobrevivientes a los 28 días en este mismo grupo de PN la incidencia fue 75 por cento (p < 0,05 (Fisher)). Se puede plantear que en la medida que aumenta la sobrevida de los RN de muy bajo peso, aumenta también la incidencia de DBP. Se encontró una asociación significativa entre DBP con DAP y RA, DAP se presentó en 33/181 vs. 10/19 (p < 0,01) y RA en 16/181 vs. 6/19 (p <0,01) en el grupo sin DBP vs. el grupo con DBP. La presencia de EMH no mostró diferencias significativas en ambos grupos

Regulation of prolactin secretion by dopamine and thyrotropin-releasing hormone in lactating rat adenohypophyses: influence of intracellular age of the hormone.

We studied the effect of dopamine (DA) on the rate of processing of PRL after biosynthesis and, with TRH, on the secretion of PRL of different intracellular ages. In these studies anterior pituitary (AP) PRL of lactating rats was pulse labeled either in vivo with [3H]leucine (3 microCi/g BW, injected iv 0.2, 1, 4, 8, 16, or 24 h before removing the AP for incubation) or in vitro with [3H]- or [14C]leucine (5 microCi/ml Krebs-Ringer bicarbonate buffer for 5 min), followed by a chase period of 15-240 min of AP fragments in medium 199. Also, to determine if endogenous DA influenced PRL synthesis, the rate of [14C]-leucine incorporation into PRL was determined in AP fragments from alpha-methyl-p-tyrosine (alpha MpT)-pretreated (200 mg/kg BW) rats. Tissue and medium PRL levels were quantified by polyacrylamide gel electrophoresis densitometric and liquid scintillation techniques. In APs from alpha MpT-treated animals [14C]-leucine incorporation into PRL increased about 30% above control values after the 5-min pulse period, and the release of labeled PRL from alpha MpT-treated APs was about 80% higher than control values after 4 h of incubation. On the other hand, when DA (50 microM) was present in the incubation medium, AP concentrations and release of in vitro synthesized [3H]PRL were significantly decreased (45-55% compared to control values; P less than 0.001). The [3H]PRL concentration, but not that of total, i.e. unlabeled PRL, fell within the AP as the time from in vivo pulse labeling to removal of the pituitary gland increased from 8 to 24 h, thus suggesting that a loss of labeled hormone occurred as it aged within the gland. Also, it was found that biosynthesis and/or processing of PRL were markedly depressed in APs from rats whose pups were removed for 24 h. Under basal conditions, in vitro secretion of [3H]PRLs during the first 30-60 min of incubation consisted primarily of mature [3H]PRL, i.e. those labeled 4 and 8 h previously, whereas newly synthesized (labeled 0.2 and 1 h previously) and old [3H]PRL (labeled 16 and 24 h previously) were secreted at much lower rates. These data confirm previous in vivo and in vitro results on the sequential release of different age PRLs. DA (17 microM) had a significantly greater inhibitory effect on newly synthesized and older stored PRL than on PRL labeled 4-8 h previously. The converse was true with regard to the PRL stimulatory effects of TRH; it provoked greater stimulation of PRL labeled 4-8 h before incubation, thus suggesting an interdependence of the actions of DA or TRH with intracellular age of the hormone.