Developmental changes in LH secretion by male pituitaries in vitro: from the infantile to adult period

Bello‐Pineda, Javier; Luna, J.; Romano, M. I.; Mendoza, M.E

doi:10.1677/joe.0.1600333

Cited by 8 publications

(12 citation statements)

References 26 publications

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“…The albino rat was chosen as an animal model, as data from rats on aspartame closely resemble human data [26]. The ages studied ranged from 3 months (age of administration) to 9 months (age of sacrifice) according to the established classification of Bello-Pineda et al [27]. Adult age was chosen as the main period of reproductive concern.…”

Section: Discussionmentioning

confidence: 99%

Chronic effect of aspartame versus stevioside on the cerebellar cortex of the adult albino rat

Mohamed¹

2013

The Egyptian Journal of Histology

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IntroductionSweeteners have evolved rapidly over the last 20 years and are added to a wide variety of food items, drinks, drugs, and hygiene products. Aspartame is the most frequently used artificial sweetener. In contrast, stevioside is a sweet herb that seemed to be a promising natural candidate to replace artificial sweeteners but was found to have hazardous effects on the male reproductive system. ObjectivesThe aim of this work was to compare between the histological changes in the cerebellar cortex of adult rats after administration of aspartame and stevioside for 6 months. The reversibility of these changes was also evaluated. Materials and methodsA total of 25 albino rats aged 3 months were used in this study. They were divided into five groups comprising five rats each. The first group was the control group. Rats in the second group were given stevioside at a dose of 8.6 mg/day for 6 months. Rats in the third group were given stevioside for 6 months and were then allowed 1 month for recovery. Rats in the fourth group were given aspartame at a dose of 20 mg/day for 6 months. Rats in the fifth group were given aspartame for 6 months and were then allowed 1 month for recovery. Specimens of the cerebellar cortex were processed for H&E and subjected to immunohistochemical staining for glial fibrillary acidic protein (GFAP) and caspase-3 and electron microscopic study. Morphometric and statistical analyses were performed to count the number of Purkinje cells, the number of granular cells, and the number of GFAP and caspase-3 immunostained cells. ResultsThe present study showed degenerative changes in the Purkinje and granular cell layers in both the aspartame-treated and stevioside-treated groups. This was confirmed by a significant increase in caspase-positive cells and a significant decrease in cell number. Moreover, there was marked increase in the number of astrocytes in areas of degeneration. This was confirmed by a significant increase in GFAP immunostaining. Recovery from stevioside was better than that from aspartame, as evidenced by the normal histological appearance of Purkinje cells and less vacuolated neuropils. This was supported by a significant increase in the number of neurons, significant decrease in caspase-positive cells, and significant decrease in GFAP immunostaining in the recovery group from stevioside compared with the recovery group from aspartame. ConclusionCessation of stevioside gives better results and leads to better improvement of the histological picture of the cerebellar cortex compared with cessation of aspartame.

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Section: Discussionmentioning

confidence: 99%

Chronic effect of aspartame versus stevioside on the cerebellar cortex of the adult albino rat

Mohamed¹

2013

The Egyptian Journal of Histology

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“…Pituitary cell cultures from PN5 and PN15 male rats responded to GnRH-stimulation with a 6-and 14-fold increase in LH secretion, respectively, whereas E19 fetal cultures failed to respond to GnRH. Although the mechanisms for these developmental changes are unclear, pituitary cell cultures from infant rats are known to be more responsive to GnRH stimulation than are adult pituitary cultures (35)(36)(37), and others have been unable to detect LH in the culture medium when fetal pituitary cells are stimulated by GnRH (38). Low levels of GnRH-R mRNA in the fetal pituitary may explain the absence of a GnRH effect (2).…”

Section: Discussionmentioning

confidence: 99%

Developmental Changes in Pituitary Adenylate Cyclase Activating Polypeptide Expression during the Perinatal Period: Possible Role in Fetal Gonadotroph Regulation

et al. 2009

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Normal reproductive functioning may require secretion of LH independently of FSH. Variation in GnRH pulse frequency and inhibin negative feedback are mechanisms for differential gonadotropin regulation; however, the first instance of differential regulation in rats is during fetal development, prior to the establishment of GnRH connections, when LH accumulates appreciably 2-4 d prior to FSH. Pituitary adenylate cyclase activating polypeptide (PACAP) can differentially regulate the gonadotropins in vitro by stimulating alpha-subunit transcription, lengthening LHbeta transcripts and decreasing FSHbeta mRNA levels, probably through stimulation of follistatin transcription. These experiments are the first to examine whether PACAP influences gonadotroph function in perinatal pituitaries. In vivo, pituitary PACAP mRNA and peptide levels were high at embryonic d 19 and declined by 94 and 85%, respectively, after parturition. This was accompanied by a decrease of 65 and 96% in total follistatin and follistatin-288 mRNAs. These changes were temporally associated with a 20- and 6.5-fold rise in FSHbeta and GnRH receptor mRNAs, respectively, with no significant increase in LHbeta mRNA. In pituitary cell cultures from fetal and postnatal male rats, PACAP mRNA levels were likewise highest in fetal cultures in which the PACAP 6-38 antagonist decreased alpha-subunit and increased FSHbeta mRNA. PACAP 6-38 also reduced basal and GnRH-stimulated LH secretion with little effect on FSH. These data support the hypothesis that PACAP expressed at high levels in the fetal pituitary stimulates alpha-subunit expression and LH secretion and restrains FSH synthesis relative to LH and that a decline in PACAP allows for the neonatal rise in FSH and GnRH receptor because follistatin is decreased.

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“…At postnatal stages, infantile and adult, we observed that type I/III collagen persisted as inducer of dispersed pituitary cell migration. During the infantile period this response has been correlated with the intense pituitary cell re-accommodation observed (Yashiro et al, 1981;Soji et al, 1994;Bello-Pineda et al, 1999). In the adult period, although male pituitary gland cytoarchitecture is relatively stable, cell movements have to be present for cell renewal (Takahashi et al, 1984;Carbajo-Pérez and Watanabe, 1990).…”

Section: Discussionmentioning

confidence: 97%

“…An increase in number and distribution throughout the gland of folliculo-stellate cells are observed with age, reaching a plateau at 40 days of age (Soji et al, 1994). In addition, LH-positive cells in adult pituitary cells are located near the periphery and at the anterior-ventral area of the gland (Nakane, 1968(Nakane, , 1970Bello-Pineda et al, 1999), but infantile glands showed that these cells are localized mainly along the anterior face of the gland, forming a band (Bello-Pineda et al, 1999). According to this, during the first weeks after birth, pituitary cells have to re-arrange in order to obtain the cytoarchitecture present in the adult gland.…”

Section: Introductionmentioning

confidence: 99%

Differences in cell migration of cultured pituitary cells from infantile and adult rats: participation of the extracellular matrix and epidermal growth factor

González

Solano-Agama

Pliego³

et al. 2004

Intl J of Devlp Neuroscience

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During early postnatal development in the rat, the tissue architecture of the pituitary gland shows changes, revealing an intense migration process of the cells. The aim of this work was to examine anterior pituitary cell migration over type I and III collagen as well as type IV collagen, of cultured pituitary cells from infantile rats and adult rats, and the participation of the epidermal growth factor in this process. Differences in cell migration rate over these two types of collagen substrates were observed at both ages, and all in all, three times more cells migrated over type I/III collagen than over type IV collagen. These data show the migration-promoting role of type I/III collagen for pituitary cells. Furthermore, when infantile cells were challenged to migrate over bovine serum albumin, the migration rate diminished, and, on the contrary, adult cell migration was higher. However, over collagen, infantile cells increased their migration rate with epidermal growth factor stimulation and adult cells showed a decrease in migration when the growth factor was in the medium. During migration, pituitary cells associated and arranged in clusters. This behavior increased in the presence of epidermal growth factor in the infantile cultures. Moreover, epidermal growth-factor-stimulated infantile cells formed larger aggregates. Adult cells also showed associative behavior, but more cells were observed isolated than in cluster arrangements and the growth factor did not induce changes in this behavior. Results showed a difference in the response of cell migration and cell association capacity to epidermal growth factor after migration of infantile and adult pituitary cells. With these observations we propose that epidermal growth factor is a cell regulator of the pituitary tissue re-arrangement process during the infantile period.

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Developmental changes in LH secretion by male pituitaries in vitro: from the infantile to adult period

Cited by 8 publications

References 26 publications

Chronic effect of aspartame versus stevioside on the cerebellar cortex of the adult albino rat

Chronic effect of aspartame versus stevioside on the cerebellar cortex of the adult albino rat

Developmental Changes in Pituitary Adenylate Cyclase Activating Polypeptide Expression during the Perinatal Period: Possible Role in Fetal Gonadotroph Regulation

Differences in cell migration of cultured pituitary cells from infantile and adult rats: participation of the extracellular matrix and epidermal growth factor

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