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Toriz CG, Melo AI, Solano-Agama C, Gómez-Domínguez EG, Martínez-Muñoz MDLA, Castañeda-Obeso J, Vera-Aguilar E, Aguirre-Benítez EL, Romero-Aguilar L, González-del Pliego M, Jiménez-Estrada I, Luna M, Pardo JP, Camacho J, Mendoza-Garrido ME. Physiological changes of growth hormone during lactation in pup rats artificially reared. PLoS One 2019; 14:e0220853. [PMID: 31408482 PMCID: PMC6692037 DOI: 10.1371/journal.pone.0220853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 07/24/2019] [Indexed: 12/19/2022] Open
Abstract
During the lactation period, rat pups are fed by the dam, and the patterns of mother-pup interaction change during this period. Additionally, there are changes in feeding; first, mother´s milk is the only food needed for sustenance, and later, it is combined with solid food and water. GH serum concentrations depend on both maternal-pup interaction and energy metabolism. In the artificial rearing (AR) procedure, pups are deprived of mother-pup interaction, and the feeding pattern is controlled. This rearing paradigm has been used in rats to analyze the effects of maternal deprivation on social behavior. In the present study, we analyzed the variation in GH, acylated ghrelin and IGF-1 serum concentrations throughout the lactation period in AR pups. At pnd7, the maternal rearing (MR) pups responded to a 4 h fast with a drop in GH serum concentration, which is a well-known response to maternal deprivation. GH serum levels in the AR pups did not change, suggesting an adaptation phenomenon. A dopamine inhibitory effect of GH secretion was observed in pnd7 cultured somatotropes, suggesting dopamine regulation of GH secretion at this age. Acylated ghrelin serum levels in the AR pups showed an inverted pattern compared to that in the MR pups, which was related to the artificial feeding pattern. IGF-1 serum levels were lower in the AR pups than in MR pups, which was associated with hepatic GH resistance and with low Igf1 mRNA expression at pnd7. Interestingly, at pnd14, both pup groups showed high hepatic Igf1 mRNA expression but low IGF-1 serum levels, and this was inverted at pnd21. However, serum glucose levels were lower in the AR pups at pnd14 but reached the same levels as the MR pups at pnd21. Moreover, hepatomegaly and higher hepatic GH-receptor levels were observed in the AR pups at pnd21, which was in agreement with an absence of a solid food meal. During AR, the pups lost the maternal interaction-stimulated GH secretion, which correlated with lower IGF-1 serum levels during the first week of postnatal development. Later, the AR pups exhibited hepatic responses, in order to satisfy the metabolic demand for the normal weaning, with low carbohydrates levels in their meal.
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Affiliation(s)
- Cesar G. Toriz
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
| | - Angel I. Melo
- Centro de Investigación en Reproducción Animal, CINVESTAV-IPN ‐Universidad Autónoma de Tlaxcala, Ixtacuixtla, Tlaxcala, Mexico
| | - Carmen Solano-Agama
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
| | - Edgar Giovanhi Gómez-Domínguez
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
| | | | - Jorge Castañeda-Obeso
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
| | | | - Elsa Liliana Aguirre-Benítez
- Departamento de Embriología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | | | - Margarita González-del Pliego
- Departamento de Embriología, Facultad de Medicina, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
| | - Ismael Jiménez-Estrada
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
| | - Maricela Luna
- Instituto de Neurobiología, UNAM, Neurobiología Celular y Molecular, Juriquilla, Queretaro, Mexico
| | - Juan Pablo Pardo
- Departamento de Bioquímica, Facultad de Medicina, UNAM, Mexico City, Mexico
| | - Javier Camacho
- Departamento de Farmacología, CINVESTAV-IPN, Mexico City, Mexico
| | - Maria Eugenia Mendoza-Garrido
- Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Mexico City, Mexico
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