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Furigo IC, Suzuki MF, Oliveira JE, Ramos-Lobo AM, Teixeira PDS, Pedroso JA, de Alencar A, Zampieri TT, Buonfiglio DC, Quaresma PGF, Prada PO, Bartolini P, Soares CRJ, Donato J. Suppression of Prolactin Secretion Partially Explains the Antidiabetic Effect of Bromocriptine in ob/ob Mice. Endocrinology 2019; 160:193-204. [PMID: 30462197 DOI: 10.1210/en.2018-00629] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/15/2018] [Indexed: 11/19/2022]
Abstract
Previous studies have shown that bromocriptine mesylate (Bromo) lowers blood glucose levels in adults with type 2 diabetes mellitus; however, the mechanism of action of the antidiabetic effects of Bromo is unclear. As a dopamine receptor agonist, Bromo can alter brain dopamine activity affecting glucose control, but it also suppresses prolactin (Prl) secretion, and Prl levels modulate glucose homeostasis. Thus, the objective of the current study was to investigate whether Bromo improves insulin sensitivity via inhibition of Prl secretion. Male and female ob/ob animals (a mouse model of obesity and insulin resistance) were treated with Bromo and/or Prl. Bromo-treated ob/ob mice exhibited lower serum Prl concentration, improved glucose and insulin tolerance, and increased insulin sensitivity in the liver and skeletal muscle compared with vehicle-treated mice. Prl replacement in Bromo-treated mice normalized serum Prl concentration without inducing hyperprolactinemia. Importantly, Prl replacement partially reversed the improvements in glucose homeostasis caused by Bromo treatment. The effects of the Prl receptor antagonist G129R-hPrl on glucose homeostasis were also investigated. We found that central G129R-hPrl infusion increased insulin tolerance of male ob/ob mice. In summary, our findings indicate that part of Bromo effects on glucose homeostasis are associated with decrease in serum Prl levels. Because G129R-hPrl treatment also improved the insulin sensitivity of ob/ob mice, pharmacological compounds that inhibit Prl signaling may represent a promising therapeutic approach to control blood glucose levels in individuals with insulin resistance.
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Affiliation(s)
- Isadora C Furigo
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Miriam F Suzuki
- Biotechnology Center, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, São Paulo, SP, Brazil
| | - João E Oliveira
- Biotechnology Center, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, São Paulo, SP, Brazil
| | - Angela M Ramos-Lobo
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Pryscila D S Teixeira
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - João A Pedroso
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Amanda de Alencar
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Thais T Zampieri
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Daniella C Buonfiglio
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Paula G F Quaresma
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
- Department of Internal Medicine, State University of Campinas, Campinas, São Paulo, SP, Brazil
| | - Patricia O Prada
- School of Applied Sciences, State University of Campinas, Limeira, São Paulo, SP, Brazil
| | - Paolo Bartolini
- Biotechnology Center, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, São Paulo, SP, Brazil
| | - Carlos R J Soares
- Biotechnology Center, Instituto de Pesquisas Energéticas e Nucleares, IPEN-CNEN/SP, São Paulo, SP, Brazil
| | - Jose Donato
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
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Furigo IC, Kim KW, Nagaishi VS, Ramos-Lobo AM, de Alencar A, Pedroso JAB, Metzger M, Donato J. Prolactin-sensitive neurons express estrogen receptor-α and depend on sex hormones for normal responsiveness to prolactin. Brain Res 2014; 1566:47-59. [PMID: 24751572 DOI: 10.1016/j.brainres.2014.04.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/10/2014] [Accepted: 04/12/2014] [Indexed: 11/26/2022]
Abstract
Estrogens and prolactin share important target tissues, including the gonads, brain, liver, kidneys and some types of cancer cells. Herein, we sought anatomical and functional evidence of possible crosstalk between prolactin and estrogens in the mouse brain. First, we determined the distribution of prolactin-responsive neurons that express the estrogen receptor α (ERα). A large number of prolactin-induced pSTAT5-immunoreactive neurons expressing ERα mRNA were observed in several brain areas, including the anteroventral periventricular nucleus, medial preoptic nucleus, arcuate nucleus of the hypothalamus, ventrolateral subdivision of the ventromedial nucleus of the hypothalamus (VMH), medial nucleus of the amygdala and nucleus of the solitary tract. However, although the medial preoptic area, periventricular nucleus of the hypothalamus, paraventricular nucleus of the hypothalamus, retrochiasmatic area, dorsomedial subdivision of the VMH, lateral hypothalamic area, dorsomedial nucleus of the hypothalamus and ventral premammillary nucleus contained significant numbers of prolactin-responsive neurons, these areas showed very few pSTAT5-immunoreactive cells expressing ERα mRNA. Second, we evaluated prolactin sensitivity in ovariectomized mice and observed that sex hormones are required for a normal responsiveness to prolactin as ovariectomized mice showed a lower number of prolactin-induced pSTAT5 immunoreactive neurons in all analyzed brain nuclei compared to gonad-intact females. In addition, we performed hypothalamic gene expression analyses to determine possible post-ovariectomy changes in components of prolactin signaling. We observed no significant changes in the mRNA expression of prolactin receptor, STAT5a or STAT5b. In summary, sex hormones exert a permissive role in maintaining the brain's prolactin sensitivity, most likely through post-transcriptional mechanisms.
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Affiliation(s)
- Isadora C Furigo
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Ki Woo Kim
- Department of Pharmacology, Institute of Lifestyle Medicine, and Nuclear Receptor Research Consortium, Yonsei University Wonju College of Medicine, Wonju 220-701, Republic of Korea
| | - Vanessa S Nagaishi
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Angela M Ramos-Lobo
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Amanda de Alencar
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - João A B Pedroso
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Martin Metzger
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Jose Donato
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
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