摘要:

When histological sections of noninnervated kidney grafts of pituitary pars intermedia were immunohistochemically processed for the demonstration of either alpha melanocyte-stimulating hormone or adrenocorticotropic hormone, chromophilic (dark) and chromophobic (light) cells could be detected. The latter, which were not detected in the intact intermedia, were interpreted as hyperactive cells, since they lacked secretory granules and displayed an increased nuclear area. The administration of ergocryptine prevented the development of light cells. Moreover, after chronic stress (swimming), some cells appeared less intensely granulated than dark cells. The results suggest that the pars intermedia is composed of parenchymal cells with different sensitivities to dopamine. Light cells would be subject to a greater dopamine-induced inhibitory influence than dark cells. The appearance of partially degranulated cells after stress points to a participation of the grafts in this event and indicates that innervation of the intermedia is not an indispensable condition for its contribution to stress.

ISSN:0028-3835    

DOI:10.1159/000125084

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Immunoreactive (IR) prolactin was localized immunocytochemically in cell bodies in the mediobasal hypothalamus and in fibers in many regions of the rat brain. The cell bodies were found in the arcuate nuclei and the adjacent areas ventral to the ventromedial nuclei. Fiber projections extended rostrally to and/or through the anterior hypothalamus, preoptic area, nucleus accumbens, septum, diagonal bands of Broca, caudate-putamen, frontal cortex and accessory olfactory bulb; laterally to the amygdala, especially the central nucleus and some parts of the medial nucleus; caudally to and/or through the midbrain central gray, reticular formation, parabrachial region, and several portions of the lower brain stem and spinal cord extending to sacral levels. The system appears to be essentially identical to that containing pro-opiomelanocortin (POMC) and its processed peptides, as shown by double immunocytochemistry. Preabsorption of the antiprolactin antiserum with either prolactin or the 16,000-dalton N-terminus of POMC eliminated immunoreactivity in the brain. Preabsorption with other POMC-derived peptides, including β-lipotropic hormone, β-endorphin, met-enkephalin, adrenocorticotrophic hormone (1–24), corticotropin-like intermediate lobe peptide, α- and γ-melanocyte-stimulating hormones and an octapeptide region of the N-terminus of POMC bearing some homology with prolactin, did not eliminate immunoreactivity in the brain. Similarly, preabsorption with growth hormone, luteinizing hormone, follicle-stimulating hormone, motilin or fetuin did not eliminate immunoreactivity in the brain. The antiprolactin antiserum also recognized all cells in the intermediate lobe and a subset of cells in the anterior lobe of the Snell dwarf mouse pituitary. This immunoreactivity was eliminated by preabsorption of the antiserum with prolactin or with the 16,000-dalton N-terminus of POMC. These results suggest that IR prolactin in the brain may be related to the N-terminus of POMC. Additional results based on one- and two-dimensional gel electrophoresis and immunoblotting indicate that the antiprolactin antiserum used in the majority of the immunocytochemical studies recognized a number of pro

ISSN:0028-3835    

DOI:10.1159/000125085

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Cells whose nuclei accumulated 3H-estradiol were identified autoradiographically in fixed, frozen sections of colchicine-treated rat hypothalamus (n = 3 animals). After autoradiogramm development, these sections were subjected to immunocytochemistry using rabbit antirat prolactin antiserum and the avidin-biotinylated horseradish peroxidase method. In the hypothalamus, a substantial subset of the neurons containing immunoreactive prolactin accumulated 3H-estradiol in their nuclei: of 3,642 immunoreactive cells examined, 1,216 had autoradiographically labeled nuclei, or about 33%. The immunoreactive prolactin neurons with autoradiographically labeled nuclei were located in the medial basal hypothalamus intermingled with immunoreactive prolactin neurons whose nuclei were not labeled autoradiographically. Since hypothalamic immunoreactive prolactin neurons have a rich and widely distributed fiber system, the present results suggest that estrogen, acting through a subset of these neurons, can modify directly the neuronal activity of several brain regions which regulate diverse aspects of the reproductive effort. Also, since immonoreactive prolactin and immunoreactive β-endorphin exist in the same hypothalamic cell population, opioid peptides derived from pro-opiomelanocortin may mediate some effects of estrogen on the neural circuitry regulating reproduction

ISSN:0028-3835    

DOI:10.1159/000125086

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

In vivo perfusion of the olfactory bulbs (OB) of freely behaving male rats by means of miniaturized push-pull cannulae (PPC) revealed consistently detectable and relatively stable levels of norepinephrine (NE) output. Introduction of a receptive female rat into the male’s cage on three separate occasions resulted in a threefold increase in NE output following the second and third, but not the first exposure. No increase in NE was obtained when perfused males were similarly exposed to male rats or in the absence of social stimulation. These results demonstrate a complex, discriminatory in vivo response of the OB noradrenergic system in male rats which may be critically involved in the receipt and processing of socially stimulated memory/recognition cues related to reproductio

ISSN:0028-3835    

DOI:10.1159/000125087

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The circadian rhythm of serum prolactin was determined in 12 patients with seizures, and 28 age- and sex-matched healthy subjects (14 men and 14 women). Blood was also collected every 15 min for 2 h immediately after a simultaneously video/EEG-documented epileptic (6 patients) and psychogenic seizure (5 patients) for the determination of prolactin, thyrotropin, growth hormone, cortisol, melatonin, catecholamines and serotonin. During the seizure-free interval, the circadian profile of serum prolactin was lower in female patients than in healthy women. Serum prolactin, thyrotropin, growth hormone, and cortisol were increased postictally, followed by a decrease, after a grand mal or complex partial seizure, but not after a psychogenic seizure in comparison to baseline serum hormone levels obtained during the same time on a seizure-free day. During the seizure and for 2 h afterwards, blood serotonin, serum melatonin, dopamine, and epinephrine did not alter and were within the reference limits of healthy subjects. Serum norepinephrine was lower in patients compared to healthy subjects (p < 0.05). The simultaneous elevation of serum prolactin, thyrotropin, growth hormone, and cortisol points to a central stimulation of the hypothalamic-pituitary axis during an epileptic seizure, but not during seizures of psychogenic origin.

ISSN:0028-3835    

DOI:10.1159/000125088

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Corticosterone (CORT) induces responses in brain cells that are mediated by glucocorticoid receptors through regulation of gene activity. We previously found rapid increases in select poly(A)-containing RNAs in rat hippocampus following treatment with CORT that are mediated by low-affinity glucocorticoid receptors. To determine if these responses are hippocampal specific, we examined RNA responses to glucocorticoids in several brain regions, myocardium, and cultured astrocytes by two-dimensional gel electrophoretic resolution of 35S-methionine labelled, in vitro translation products. RNAs coding for similar 35-, 33-, and 20-kdalton polypeptides are induced after 3 days of CORT treatment (40 mg/kg/day) in hippocampus, hypothalamus, cortex, striatum, cerebellum, and myocardium. Primary astrocyte cultures (neonatal rat), however, showed increases after hydrocortisone (1 µg/ml) in only the 20- and 33-kdalton translation products, while the 35-kdalton polypeptide was not detected. The hippocampal responses were maintained for up to 3 months during chronic daily CORT treatment. To determine if an increase in endogenous CORT levels would also evoke the RNA responses, we subjected rats to 2 h of vibratory stress and analyzed the in vitro translation products. RNAs coding for the 35- and 20-kdalton polypeptides were increased 3- to 5-fold in the hippocampus after acute stress in intact rats, but not in stressed adrenalectomized rats. These results suggest a new class of molecular stress responses in brain cells that is glucocorticoid dependent under physiological conditions

ISSN:0028-3835    

DOI:10.1159/000125089

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

We have studied the development of the hypothalamic-pituitary vascular connections in the fetal sheep using ink-filling techniques. The presence of ink-filled vessels in components of the hypothalamic-pituitary axis is interpreted as indicating patency of the system. Ink-filled vessels were identified in the median eminence, the pituitary stalk and the pituitary gland as early as 45 days of gestation and at all subsequent ages investigated. These results suggest that the pituitary could potentially respond to hypothalamic releasing factors from as early as 45 days of gestation in the fetal sheep.

ISSN:0028-3835    

DOI:10.1159/000125090

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

Steroid autoradiography was undertaken to determine the neuroanatomical loci which might be involved in the activation of steroid-sensitive behaviors in the Japanese quail (Coturnix japonica). Male and female quail were either surgically gonadectomized or photically regressed and implanted with androgen or estrogen to restore normal sexual and courtship behavior. After gonadectomy or implant removal, each quail was injected with 250 µCi of [3H]-testosterone (3H-T), [3H]-estradiol (3H-E2), or [3H]-dihydrotestosterone (3H-DHT), sacrificed, processed for autoradiography, and the telencephalon, diencephalon, mesencephalon, and rhombencephalon were examined for labelled cells. Following 3H-T or 3H-E2 injection and autoradiography, labelled cells were found in nucleus septalis lateralis (SL), nucleus preopticus medialis (POM), nucleus paraventricularis (PVN), regio lateralis hypothalami (LHy), nucleus inferior hypothalami (IH), nucleus infundibuli (IN), nucleus intercollicularis (ICo), substantia grisea centralis (GCt), nucleus taeniae (Tn), and in the reticular formation near nucleus motorius nervi trigemini (MV). In addition, following 3H-E2 autoradiography, labelled cells were found around nucleus accumbens (Ac). Following 3H-DHT autoradiography, labelled cells were found only in SL, PVN, Tn, LHy, ICo, and CGt. No labelled cells were found in Ac, POM, IH, IN, or MV even after long exposure times. These results suggest that the nuclei labelled following 3Η-E2 but not 3H-DHT administration bind exclusively the aromatized metabolites of T. Since quail show a sex difference in male-typical copulatory behavior in response to E2, labelled cells were counted in POM, LHy, IH, and Tn of male and female quail following 3Η-E2 injection and autoradiography. No sex differences in the number of labelled cells were found in POM, LHy, or IH. Males were found to have more labelled cells than females in Tn. These results show that sex differences in male-typical copulatory behavior are not due to sex differences in the number of cells binding estrogens in POM. The results reported here constitute the most neuroanatomically extensive report of steroid binding cells to date for a galliform brain, the first comparison in a galliform bird of the distributions of cells labelled following injection of 3H-T, 3H-E2, and 3H-DHT and the first analysis of sex differences in numbers of estrogen-binding cells in four nuclei in the avian bra

ISSN:0028-3835    

DOI:10.1159/000125091

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The results of a seasonal study of the regulation by steroids of ovine pineal β-adrenoceptors are reported. The effects of ovariectomy, steroid implants and superior cervical ganglionectomy were investigated in Merino ewes. The results confirm earlier observations showing a seasonal variation in the sensitivity of the receptors to modification by gonadal steroids. A marked difference in receptor density and affinity between the follicular and luteal phases of the estrous cycle is shown for the first time, a difference which can be modified by appropriate steroid-related treatments. A season-dependent antagonism between the sympathetic innervation of the gland (presumably acting via the neurotransmitter noradrenaline) and gonadal steroids in the regulation of ovine pineal β-adrenoceptor function is also show

ISSN:0028-3835    

DOI:10.1159/000125092

出版商:S. Karger AG    

年代:1989

数据来源: Karger

摘要:

The present study was performed to gain more information on the nature of the opioid peptide(s) involved in the mechanism of action of α-methyldopa. Conscious, normotensive Wistar rats were used and all treatments were given intracisternally. For blood pressure and heart rate, pretreatment with a midportion β-endorphin antiserum resulted in a parallel shift to the right of the dose-response curve for α-methyldopa. In addition, when rats were pretreated with various dilutions of this antiserum and treated with a constant dose of α-methyldopa, the antiserum dose-dependently inhibited α-methyldopa-induced hypotension and bradycardia. Using antisera specifically recognizing the C-terminus of β-, γ- and α-endorphin, respectively, revealed that only the β-endorphin antiserum inhibited the decrease in blood pressure seen after administration of α-methyldopa. An antiserum against [Met5]enkephalin did not influence the cardiovascular responses following α-methyldopa. On the other hand, a dynorphin(1–13) antiserum also inhibited in a dose-dependent manner the hypotension induced by α-methyldopa. When administered 3 h after the injection of α-methyldopa, the β-endorphin and dynorphin(1–13) antisera failed to reverse the hypotension induced by α-methyldopa. The results favor a role for β-endorphin(1-31) and dynorphin(l-13) in the hypotension centrally media

ISSN:0028-3835    

DOI:10.1159/000125093

出版商:S. Karger AG    

年代:1989

数据来源: Karger