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Seale AP, Yamaguchi Y, Johnstone WM, Borski RJ, Lerner DT, Grau EG. Endocrine regulation of prolactin cell function and modulation of osmoreception in the Mozambique tilapia. Gen Comp Endocrinol 2013; 192:191-203. [PMID: 23722201 DOI: 10.1016/j.ygcen.2013.05.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 05/11/2013] [Accepted: 05/14/2013] [Indexed: 01/06/2023]
Abstract
Prolactin (PRL) cells of the Mozambique tilapia, Oreochromis mossambicus, are osmoreceptors by virtue of their intrinsic osmosensitivity coupled with their ability to directly regulate hydromineral homeostasis through the actions of PRL. Layered upon this fundamental osmotic reflex is an array of endocrine control of PRL synthesis and secretion. Consistent with its role in fresh water (FW) osmoregulation, PRL release in tilapia increases as extracellular osmolality decreases. The hyposmotically-induced release of PRL can be enhanced or attenuated by a variety of hormones. Prolactin release has been shown to be stimulated by gonadotropin-releasing hormone (GnRH), 17-β-estradiol (E2), testosterone (T), thyrotropin-releasing hormone (TRH), atrial natriuretic peptide (ANP), brain-natriuretic peptide (BNP), C-type natriuretic peptide (CNP), ventricular natriuretic peptide (VNP), PRL-releasing peptide (PrRP), angiotensin II (ANG II), leptin, insulin-like growth factors (IGFs), ghrelin, and inhibited by somatostatin (SS), urotensin-II (U-II), dopamine, cortisol, ouabain and vasoactive intestinal peptide (VIP). This review is aimed at providing an overview of the hypothalamic and extra-hypothalamic hormones that regulate PRL release in euryhaline Mozambique tilapia, particularly in the context on how they may modulate osmoreception, and mediate the multifunctional actions of PRL. Also considered are the signal transduction pathways through which these secretagogues regulate PRL cell function.
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Affiliation(s)
- A P Seale
- Hawai'i Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA.
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2
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Melamed P, Gur G, Rosenfeld H, Elizur A, Yaron Z. Possible interactions between gonadotrophs and somatotrophs in the pituitary of tilapia: apparent roles for insulin-like growth factor I and estradiol. Endocrinology 1999; 140:1183-91. [PMID: 10067842 DOI: 10.1210/endo.140.3.6571] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The unique organization of the teleost pituitary, in which cells are grouped according to their characteristic hormone, makes this a suitable model for studying pituitary paracrine interactions. In a number of fish, including tilapia, there are variations in the circulating levels of the gonadotropins and GH, which are elevated during the reproductive season, suggesting interactions between the reproductive and growth axes. The aim of this study was to investigate paracrine interactions between the gonadotrophs and somatotrophs in the tilapia pituitary. Initially, dispersed pituitary cells were separated on a density gradient in which the gonadotrophs were found in the least dense fractions, and the somatotrophs were concentrated in the densest fraction. After 4 days in culture, cells in the least dense fractions showed characteristic cytoplasmic extensions not seen in the somatotrophs, which appeared small and failed to form aggregates; somatotrophs were found, however, attached to other non-GH cells. Staining of the nuclei with 4,6-diaminidino-2-phenyl-dihydrochloride revealed that the isolated somatotrophs had undergone nuclear condensation and fragmentation typical of apoptosis. Addition of either estradiol or human recombinant insulin-like growth factor I (IGF-I; 10 nM) to the somatotroph cultures increased the number of cell aggregates and reduced the number of condensed or fragmented nuclei. Immunocytochemical studies on pituitary sections revealed IGF-I immunoreactivity in regions of the proximal pars distalis that stain with gonadotropin IIbeta antisera and also in regions of the rostral pars distalis characteristic of corticotrophs; immunoreactive IGF-I was never seen in the region of the somatotrophs. Incubation of cells from the different fractions with testosterone (10 nM; 24 h) revealed that cells of the least dense fractions, which were rich in gonadotrophs, possessed aromatizing ability, which was absent in the somatotroph-enriched fraction. These results suggest that estradiol and IGF-I, both generated from cells other than the somatotrophs, may exert antiapoptotic effects and thus possibly control the size of this population of cells.
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Affiliation(s)
- P Melamed
- Department of Zoology, Tel-Aviv University, Ramat Aviv, Israel
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3
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Johnston LR, Wigham T. The effects of ions and hypothalamic factors on the in vitro activity of rainbow trout prolactin cells. Gen Comp Endocrinol 1990; 79:253-60. [PMID: 1697274 DOI: 10.1016/0016-6480(90)90111-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The influence of various ions and of dopamine and somatostatin on the in vitro activity of rainbow trout prolactin (PRL) cells was investigated. There was a positive correlation between medium Ca2+ concentration and both PRL synthesis and release up to 1.8 mM Ca2+, above which no further increase occurred. Even with no Ca2+ in the medium, there was still PRL secretion during the incubation. Replacement of Ca2+ with Ba2+ in the medium did not elevate either total PRL levels or PRL release above that in Ca2 +)-free medium. Neither elevated Mg2+ nor increased medium K+ had any effect on PRL synthesis or release. Dopamine inhibited PRL release but not synthesis, as did the D2 receptor agonist, apomorphine. However, the D2 receptor antagonist, (+)-butaclamol was unable to prevent the action of dopamine on PRL release. Somatostatin inhibited both PRL synthesis and release in normal Ca2+ medium, but release only in reduced Ca2+ medium. Thus, Ca2+, dopamine, and somatostatin may all have roles in regulating prolactin secretion in this fish. In addition, oPRL reduced trout PRL release, indicating a possible negative feedback mechanism for trout PRL secretion.
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Affiliation(s)
- L R Johnston
- School of Pure and Applied Biology, University of Wales College of Cardiff, United Kingdom
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Gonnet F, Barret A, Grouselle D, Prunet P. Hypothalamic control of prolactin release in the rainbow trout,Salmo gairdneri: in vitro studies. FISH PHYSIOLOGY AND BIOCHEMISTRY 1989; 7:301-308. [PMID: 24221786 DOI: 10.1007/bf00004721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Hypothalamic control of prolactin (PRL) release in immature rainbow troutSalmo gairdneri was investigated using anin vitro perifusion system of the rostral pars distalis. Hypothalamic extract of trout induced a dose-dependent stimulation of PRL release. A similar effect was observed when infusing the medium from a 24h static incubation of the hypothalamus. Extracts from different control tissues (muscle, liver, gut) did not changein vitro release, thus confirming the specificity of this stimulatory effect. Hypothalamic extract from adult male rat, known to contain PRL release inhibiting factors, stimulatedin vitro PRL secretion in rainbow trout. This suggests that PRL cells are predominantly influenced by PRL releasing factors. Measurement of TRH and serotonin content in trout hypothalamus indicated consistent physiological levels of these two factors. HPLC studies of hypothalamic extract showed that immunoreactive - TRH eluted at the same place as labelled TRH standard. Moreover, pizotifen, a serotonin antagonist, partially inhibited the stimulation observed with trout hypothalamic extract. These results suggest that, in immature rainbow trout, PRL release is under stimulatory hypothalamic control and that serotonin and probably TRH play a major role in this control.
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Affiliation(s)
- F Gonnet
- Laboratoire de Physiologie des Poissons, INRA, Campus de Beaulieu, 35042, Rennes Cedex, France
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5
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Olivereau M, Olivereau JM, Lambert JF. Cytological responses of the pituitary (rostral pars distalis) and immunoreactive corticotropin-releasing factor (CRF) in the goldfish treated with dopamine antagonists. Gen Comp Endocrinol 1988; 71:506-15. [PMID: 2847956 DOI: 10.1016/0016-6480(88)90281-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The in vivo effects of three dopamine (DA) antagonists on the cytology of the rostral pars distalis (RPD) were investigated in young goldfish (Carassius auratus L.). Pimozide, sulpiride, and domperidone were injected for 5 (low dose, Experiment I) and 7 days (higher dose, Experiment II). Cytological and immunocytochemical techniques using antisera to (1-24) ACTH and (1-39) ACTH, human beta-thyrotropin (TSH beta), and synthetic (1-41) CRF were applied to pituitary and brain sections. Cytometrical studies showed that the three drugs induced similar quantitative changes in the cells of the RPD. Prolactin (PRL)-secreting cell hypertrophy was significant in Experiment II, whereas the nuclear enlargement was significant in both experiments. The numbers of cytoplasmic granules were similar in control and treated goldfish. Thyrotropic (TSH) cells and their nuclei were significantly enlarged in both experiments; their content in immunoreactive TSH was not clearly modified. Corticotropic (ACTH) cells showed significant nuclear and cellular hypertrophy, and labeled granules were often concentrated along the cell membrane. The amount of immunoreactive CRF present in the rostral neurohypophysial ramifications was reduced in the majority of treated fish. Solvent-injected controls showed no significant changes in the RPD. These results suggest that DA inhibits PRL cell activity in goldfish. TSH and ACTH cells appear stimulated by DA-receptor blockers, although differential effects on synthesis and release cannot be evaluated in in vivo experiments. A release of corticotropin-releasing factor may be involved in the ACTH cell stimulation. These data are compared with those obtained in other vertebrates.
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Affiliation(s)
- M Olivereau
- Laboratoire de Physiologie, Institut Océanographique, Paris, France
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Johnston LR, Wigham T. The intracellular regulation of prolactin cell function in the rainbow trout, Salmo gairdneri. Gen Comp Endocrinol 1988; 71:284-91. [PMID: 2849574 DOI: 10.1016/0016-6480(88)90256-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The mechanisms for regulation of prolactin (PRL) secretion in the rainbow trout were investigated. The inhibitory action of dopamine on PRL release in vitro was enhanced by GTP and dopamine also reduced pituitary cAMP content. Forskolin increased both PRL release and cAMP content in vitro, but this effect was prevented by dopamine and did not occur in Ca2+-free medium. The cAMP analogue, dbcAMP increased PRL synthesis in low Ca2+ medium, though release was not significantly affected. The calcium ionophore, A23187, increased PRL release, but this effect was not seen with flunarizine, a voltage-dependent Ca2+-channel blocker. The calmodulin blocker, pimozide, increased PRL synthesis and pituitary PRL content in vivo and a second calmodulin blocker, trifluoperazine, also increased PRL synthesis, though not percentage release, in vitro. Both drugs elevated pituitary cAMP levels. These results indicate an involvement of agonist-dependent Gi proteins, Ca2+, calmodulin, and cAMP in the control of PRL cells in this teleost.
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Affiliation(s)
- L R Johnston
- Department of Applied Biology, UWIST, Cardiff, United Kingdom
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Wendelaar Bonga SE, Flik G, Löwik CW, van Eys GJ. Environmental control of prolactin synthesis in the teleost fish Oreochromis (formerly Sarotherodon) mossambicus. Gen Comp Endocrinol 1985; 57:352-9. [PMID: 3921424 DOI: 10.1016/0016-6480(85)90214-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In the cichlid fish Oreochromis mossambicus prolactin cell activity is inversely related to the osmolarity and the Ca2+ concentration of the ambient water. Prolactin cell activity was estimated, at the end of a 3-week experimental period, by determination of the rate of prolactin synthesis during incubation of the rostral parts of the pituitary gland, in the presence of [3H]lysine. Since the secretory activity of isolated prolactin cells is known to be inversely related to the osmolarity of the incubation medium, the possibility was investigated that the effects of changes in ionic composition of the ambient water on prolactin secretion in vivo are mediated by changes in osmolarity of the blood plasma. No support was found for this hypothesis. In fish exposed to high water osmolarities prolactin cell activity was reduced, while plasma osmolarity increased. In contrast, at high Ca2+ concentrations of the water, when prolactin secretion was inhibited to a similar extent, plasma osmolarity was significantly reduced. Although direct effects of plasma osmolarity on prolactin cells cannot be excluded completely, it is unlikely that plasma osmolarity is the predominant factor in the control of prolactin cell activity in situ. The physiological significance of the capacity of isolated prolactin cells to respond to changes in osmolarity of the ambient medium--a capacity shared with some other endocrine cell types--is therefore unclear.
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James VA, Wigham T. Evidence for dopaminergic and serotonergic regulation of prolactin cell activity in the trout Salmo gairdneri. Gen Comp Endocrinol 1984; 56:231-9. [PMID: 6150877 DOI: 10.1016/0016-6480(84)90035-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The control of prolactin (PRL) cell activity in Salmo gairdneri was investigated in vivo and in vitro. In some in vivo experiments treatment was followed by estimation of pituitary PRL content by gel electrophoresis or of PRL cell nuclear area by light microscopy. In the remainder, treatment was followed by incubation of the pituitary glands in drug-free medium for estimation of PRL synthesis and release. The dopamine precursor, L-dopa (20 mg/kg), reduced pituitary PRL content. Conversely, the dopamine-receptor blocker, domperidone (10 mg/kg), increased total PRL content and amount released in the subsequent incubation. The initial serotonin precursor, L-tryptophan (75 mg/kg), increased pituitary PRL content and PRL cell nuclear area. 5-HTP (20 mg/kg), the immediate serotonin precursor, increased both percentage PRL release and total PRL levels during subsequent incubation. Pargyline (25 mg/kg) treatment to inhibit serotonin catabolism elevated PRL levels in pituitary and medium during subsequent incubation. The serotonin synthesis blocker, parachlorophenylalanine (pCPA; 100 mg/kg), nonsignificantly reduced PRL cell nuclear area. When this was followed by incubation, percentage PRL release and total PRL fell significantly. During in vitro incubation, dopamine (2 micrograms/ml) reduced the release of PRL into the medium, while serotonin (10(-5) M) increased PRL release. These results suggest that both an inhibitory dopaminergic and a stimulatory serotonergic system may be involved in PRL cell regulation in S. gairdneri. The lack of any significant effect of cortisol (1 microgram/ml), somatostatin (300 ng/ml). GABA (100 mg/ml) and TRH 100 ng/ml) on PRL release in vitro suggested little or no involvement of these putative regulatory factors in PRL cell regulation.
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Wigham T, Batten TF. In vitro effects of thyrotropin-releasing hormone and somatostatin on prolactin and growth hormone release by the pituitary of Poecilia latipinna. I. An electrophoretic study. Gen Comp Endocrinol 1984; 55:444-9. [PMID: 6147295 DOI: 10.1016/0016-6480(84)90016-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Pituitary glands were removed from Poecilia latipinna which had been maintained in one-third seawater and were incubated for 18 hr in media of either 300 mosmol/kg (OP300) or 340 mosmol/kg (OP340) osmotic pressure for measurement of both total and newly synthesised prolactin (PRL) and growth hormone (GH) release. Thyrotropin-releasing hormone (TRH) at 100 ng/ml increased release of total and newly synthesised PRL into OP340, but not into OP300, medium. Conversely, 300 ng/ml of somatotropin-release-inhibiting factor (SRIF) inhibited total and newly synthesised PRL release into OP300, but not OP340, medium. At 1000 ng/ml, SRIF inhibited total PRL release into both media, but newly synthesised PRL release was reduced significantly only in OP300 medium. The release of GH was unaffected by 100 ng/ml TRH in OP300 medium, but both total and newly synthesised GH release were enhanced by this dose in OP340 medium. SRIF at 300 ng/ml reduced total GH release into OP300 medium, whereas the release of newly synthesised GH was inhibited in OP340 medium. At 1000 ng/ml, SRIF inhibited total GH release into both media, but release of the newly synthesised hormone was not significantly altered. These results suggest that TRH can stimulate and SRIF inhibit both PRL and GH release by Poecilia pituitaries, but that these effects may be modulated by plasma osmotic pressure.
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Batten TF, Young G, Ball JN. Secretory activity of Poecilia latipinna (Teleostei) pituitary in vitro: rostral pars distalis and proximal pars distalis. Gen Comp Endocrinol 1983; 51:113-30. [PMID: 6309607 DOI: 10.1016/0016-6480(83)90104-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The ultrastructure of each adenohypophysial secretory cell type was examined in pituitaries of adult female mollies (Poecilia latipinna) after various periods in vitro, and with varied medium osmotic pressure (OP), Na+, and Ca2+ concentrations. Prolactin (PRL) cells were markedly activated by 18 hr, and after 7 or 14 days were almost totally degranulated, with massive arrays of Golgi and RER. Reduction in OP, but not Na+ or Ca2+, caused an additional activation of PRL cells after periods of 18 hr or longer. Corticotroph (ACTH) cells became noticeably activated by 4 hr, and were possibly affected by OP, but not Na+ or Ca2+. Growth hormone (GH) cells were activated by 6 hr, and after 18 hr were quite degranulated with extensive arrays of RER. OP had no effect on GH cells before 3 days, when reduced OP appeared to cause an additional activation, with the appearance of large irregular secretory granule (SG)-like inclusions. Na+ and Ca2+ again had no effect. Gonadotrophic (GtH) cells appeared to be little affected by in vitro incubation; however, the very active cells from vitellogenic fish underwent a reduction in dilated RER after prolonged culture. Thyrotrophic (TSH) cells gradually became activated in vitro, but the response again varied with the sexual condition of the fish. Neither GtH nor TSH cells were affected by OP, Na+, or Ca2+. The findings are discussed in relation to hypothalamic control, via releasing/inhibiting factors, of adenohypophysial cell activity.
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Hegab SA, Hanke W. Changes in catecholamine content of the hypothalamus during adaptation of fish to changed external salinity. Gen Comp Endocrinol 1981; 44:324-34. [PMID: 7286616 DOI: 10.1016/0016-6480(81)90009-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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Olcese J, Figueroa H, Hall TR, Yurgens P, Kiebzak G, Meyer R, de Vlaming V. Effects of para-chlorophenylalanine, a brain serotonin depletor, on pituitary cyclic AMP levels in the rainbow trout, Salmo gairdneri. Gen Comp Endocrinol 1981; 43:462-6. [PMID: 6262190 DOI: 10.1016/0016-6480(81)90230-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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14
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Betchaku T, Douglas WW. Cellular composition of the rostral pars distalis of the anterior pituitary gland of the alewife, Alosa pseudoharengus, during the spawning run. Anat Rec (Hoboken) 1981; 199:403-21. [PMID: 6266281 DOI: 10.1002/ar.1091990309] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The rostral pars distalis of the anterior pituitary gland of the marine alewife, Alosa pseudoharengus, during its annual spawning run to fresh water was examined histologically. The rostral pars distalis is composed of many interconnecting follicles of various sizes. Contrary to earlier reports, the follicular epithelium contains not only prolactin (PRL) cells but corticotropic (ACTH) cell and thyrotropic (TSH) cells (in addition to two nonendocrine cell types). Basally all three endocrine cell types make direct contact with the basement membrane which separates the follicles from the neurohypophysial processes. Apically, however, only the prolactin cells, the largest of the three, protrude into the follicular lumen by means of the small ciliated apical protruberance. All other cellular elements are sealed from the follicular lumen by a layer of covering cells which have properties of transitional epithelial cells. In the follicular epithelium, the slender TSH cells are intercalated between the large conspicuous prolactin cells. The ACTH cells, the smallest of the three endocrine cells, lie in deep invaginations in the basal regions of the individual PRL cells in such a way that on cursory examination they can be mistaken for the nuclei of the latter. Only a small portion of the cellular surface of the ACTH cell escapes the enveloping prolactin cell to make contact with the basement membrane of the follicle. In teleosts, prolactin, ACTH, and TSH have all been implicated in the regulation of hydromineral metabolism and reproductive development. The intimate spatial relation between the three endocrine cells in the alewife rostral pars distalis thus raises the possibility of some functional interactions at the adenohypophysial level, perhaps as an adaptation of this anadromous teleost whose reproductive development and behavior is associated with large changes in ambient salinity. The functional significance of the follicular lumen is discussed together with possible sensory functions of the PRL cells.
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Betchaku T, Douglas WW. Fine structure of the rostral pars distalis of the adenohypophysis of the killifish, Fundulus heteroclitus, in fresh and salt water. Anat Rec (Hoboken) 1980; 198:595-609. [PMID: 7212312 DOI: 10.1002/ar.1091980405] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
A fine structural study has confirmed earlier light microscopic observations indicating that prolactin cells are the only endocrine cells present in the main body of the rostral pars distalis of the adenohypophysis of Fundulus heteroclitus, a killifish common in New England coastal waters. Some ACTH cells occurred in thin plaques applied to the neurohypophysial trunk in the posterior part of the region. In freshwater-adapted specimens the volume occupied by the prolactin cell mass was larger than in saltwater-adapted specimens and contained larger prolactin cells. A paucity of contact specializations between the parenchymal cells may facilitate their spatial rearrangement as the prolactin cell population varies with changes in ambient salinity. Many fine neurohypophysial processes penetrated deeply into the rostral pars distalis and contained Type B (aminergic) nerve fibers believed to modulate prolactin secretion. These fibers ended mainly on the basement membrane that separates the neurohypophysial processes from the parenchyma. Synaptic contacts on prolactin cells were not observed but no prolactin cell appeared to be more than five cell widths from such a nerve terminal. The results emphasize the usefulness of the rostral pars distalis of this easily obtained and maintained teleost for studies of prolactin cell function.
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Kikuyama S, Seki T. Possible involvement of dopamine in the release of prolactin-like hormone from bullfrog pituitary gland. Gen Comp Endocrinol 1980; 41:173-9. [PMID: 6968286 DOI: 10.1016/0016-6480(80)90141-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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17
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Batten TF, Ingleton PM, Ball JN. Ultrastructural and formaldehyde-fluorescence studies on the hypothalamus of Poecilia latipinna (Teleostei, Cyprinodontiformes). Gen Comp Endocrinol 1979; 39:87-109. [PMID: 573720 DOI: 10.1016/0016-6480(79)90195-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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18
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Donaldson EM, Fagerlund UH, Higgs DA, Mcbride J. Hormonal Enhancement of Growth. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/s1546-5098(08)60032-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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Taraskevich PS, Douglas WW. Catecholamines of supposed inhibitory hypophysiotrophic function suppress action potentials in prolactin cells. Nature 1978; 276:832-4. [PMID: 723958 DOI: 10.1038/276832a0] [Citation(s) in RCA: 95] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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20
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Olivereau M. Effect of pimozide on the cytology of the eel pituitary. I. Prolactin-secreting cells. Cell Tissue Res 1978; 189:219-30. [PMID: 657239 DOI: 10.1007/bf00209271] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Pimozide, a specific blocker of dopaminergic receptors, was injected for 4 to 9 days in freshwater (FW) eels or eels acclimated to sea water (SW), for 10 to 30 days. The daily dose was 100 or 200 microgram/100 g. In FW, pimozide induces a nuclear hypertrophy in the prolactin (PRL) cells of eels; these elongated cells increase in height. The amount of erythrosinophilic granules in the cytoplasm, initially reduced, increases. Plasma electrolyte values are not modified: only the plasma sodium level slightly rises with the higher dose. In SW, PRL cells appear less active. After 10 days, this hypoactivity is not yet fully evident; pimozide stimulates PRL cells without affecting electrolyte values. After 1 month in SW, PRL cells are stimulated with pimozide and a slight regranulation may occasionally occur. The response in SW is never as marked as it is in FW; a high dose is not more effective than a low one. The higher dose significantly raises Na+, Ca2+ and Cl- plasma levels. These data suggest that prolactin synthesis and release increase with pimozide. They corroborate the hypothesis of a hypothalamic inhibitory control on PRL secretion mediated through dopaminergic fibers in the eel, but other factors may also be involved in this regulation in addition to the effect of salinity.
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21
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Ingleton PM. Studies on the effects of the mammary carcinogen 7,12-dimethylbenz(a)anthracene on release and synthesis of prolactin by rat pituitaries in vitro. Eur J Cancer 1977; 13:1041-8. [PMID: 410645 DOI: 10.1016/0014-2964(77)90184-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Wigham T, Nishioka RS, Bern HA. Factors affecting in vitro activity of prolactin cells in the euryhaline teleost Sarotherodon mossambicus (Tilapia mossambica). Gen Comp Endocrinol 1977; 32:120-31. [PMID: 408224 DOI: 10.1016/0016-6480(77)90142-3] [Citation(s) in RCA: 91] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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23
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Wigham T, Ball JN. Effect of environmental salinity changes on the secretory activity of prolactin cells in ocular pituitary transplants in Poecilia latipinna (Teleostei). Gen Comp Endocrinol 1977; 31:148-53. [PMID: 832814 DOI: 10.1016/0016-6480(77)90201-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Wigham T, Ball JN. In vivo evidence for catecholaminergic inhibition of prolactin secretion in the teleostPoecilia latipinna. ACTA ACUST UNITED AC 1976. [DOI: 10.1007/bf00689303] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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