Hypothalamus and cytodifferentiation of the foetal pituitary gland

Chatelain, A.; Dubois, M. P.; Dupouy, Jean‐Paul

doi:10.1007/bf00219606

Cited by 33 publications

(12 citation statements)

References 9 publications

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“…However, a sparse opioid binding has been shown in the anterior pituitary gland (28) and opioids were not found to affect the release of ACTH from the pituitary in vivo (29). Moreover, we have previously reported that the hypothalamic content of CRF increases drastically in the developing rat from day 17 of gestation to week 4 post-partum (30), consistent with the hypothalamic control of the corticostimulating function of the pituitary gland as early as day 19 of gestation (3,31). Thus, morphine-induced activation of hypophysial±adrenocortical activity in the neonate probably occurs via the release of CRF.…”

Section: Discussionsupporting

confidence: 53%

Morphine-induced stimulation of pituitary-adrenocortical activity is mediated by activation of nitric oxide in the early stages of postnatal life in the rat

Lésage

Bernet²,

Montel³

et al. 2001

European Journal of Endocrinology

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Objective: The first aim of the present study was to determine if morphine, a prototypic m-opioid agonist drug, affects pituitary±adrenocortical activity in developing rat pups (first and second weeks of postnatal life). The second aim of this study was to explore, in vivo, if nitric oxide (NO) could be involved in the neurohormonal response to morphine in the early stages of postnatal life. Methods: Plasma ACTH and corticosterone concentrations were determined by RIA in rat pups n 5±14 rats/experimental group) after they had been killed by decapitation. In a first experiment, 1-day and 1-and 2-week-old rats were treated s.c. with morphine (20 mg/kg) or with vehicle (0.9% NaCl) and killed 5±90 min later. In a second experiment, 2-week-old pups were pretreated s.c. with naltrexone (NAL; 0.4 mg/kg or 10 mg/kg), and injected 1 h later with either morphine (20 mg/kg) or vehicle, and killed 30 min later. Some pups injected with only NAL were killed 60 or 90 min later. On the other hand, pups injected with NAL (10 mg/kg) or NAL and morphine were killed 30 min later. In a third experiment, 2-week-old pups were pretreated s.c. with N-v-nitro L arginine methylester (L-NAME; 30 mg/kg or 100 mg/kg), and injected 1 h later with either morphine (20 mg/kg) or vehicle, and killed 30 min later. Moreover, some pups injected with L-NAME (100 mg/kg) or L-NAME with morphine were killed 30 min later. In a final experiment, pups were injected s.c. with either S-nitroso-N-acetylpenicillamine (SNAP; 5 mg/kg) or vehicle, and killed 60 or 90 min later. Results: Morphine administered to rat pups elicited marked rises in both ACTH and corticosterone secretion. Moreover, these responses increased with advancing postnatal age. In 2-week-old rat pups, NAL, a competitive antagonist at m-opioid receptors, administered alone increased both plasma ACTH and corticosterone concentrations 30 min later. L-NAME, a specific NO synthase inhibitor, did not affect plasma ACTH and corticosterone concentrations 30 min later when administered alone. NAL, when concomitantly administered with morphine, was unable to block morphine responses. In contrast, morphine responses were blocked by pretreatment (60 min before) with NAL or with L-NAME. Acute injection of SNAP increased both ACTH and corticosterone release. Conclusion: Our results suggest that opioids have controversial effects on pituitary±adrenocortical activity in the early postnatal period in the rat, and that endogenous NO is one of the major factors in the response of the pituitary±adrenocortical axis to morphine.

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Section: Discussionsupporting

confidence: 53%

Morphine-induced stimulation of pituitary-adrenocortical activity is mediated by activation of nitric oxide in the early stages of postnatal life in the rat

Lésage

Bernet²,

Montel³

et al. 2001

European Journal of Endocrinology

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“…Chatelain et al (1977), however, observed immunohistochemically the first PRL cells in the fetal rats on Day 21 and the reaction strength was very weak until Day 4 post partum. Watanabe and Daikoku (1979) failed to immunohistochemically detect PRL cells in the pituitarties of fetal rats.…”

Section: Discussionmentioning

confidence: 89%

Postnatal development, sexual difference and sexual cyclic variation of prolactin cells in rats: Special reference to the topographic affinity to a gonadotroph.

Sato

1980

Endocrinol Japon

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During the postnatal development of rat pituitary it has been shown that PRL cells appear oval, polygonal or cup shaped in both sexes. The oval cells first appear on Day 10 after birth. Development of the latter two shapes is delayed to Days 20 and 30, respectively.The polygonal shaped cells become predominant with sexual maturation.Some of them surround the gonadotrophs with their elongate, cytoplasmic processes, taking on the appearance of cup cells. Although the PRL cells are more numerous in the female than in the male, the cup shaped cells are inverse. Further it is noted that the immunostainability of the oval and polygonal cells varies during the estrous cycle; the weakest reaction was revealed at estrus and the strongest at dioestrus.Those immunohistochemical findings may suggest that the oval cells are premature, the polygonal ones mature and the cup ones particularly differentiated. The topographic affinity between the cup cells and the gonadotrophs may be a morphological indication of their intimate functional relationship.

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“…It has been suggested that hypothalamic release factors could have an influence on this process [49][50][51][52]; nevertheless, embryonic pituitary cells can differentiate to LH-secreting cells in the absence of these factors [53]. In addition, extra-hypothalamic factors could have an influence on cell differentiation in the adenohypophysis; for instance, it is known that glucocorticoids stimulate differentiation of GH and PRL cells in vitro [54,55] and insulin seems to induce gonadotropic differentiation in cultures of embryonic rat adenohypophyseal cells [56].…”

Section: Could Il-1b and Il-6 Have An Influence On Hormonal Release Amentioning

confidence: 99%

Prenatal expression of interleukin 1β and interleukin 6 in the rat pituitary gland

et al. 2008

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a b s t r a c tIt is known that interleukin 1b (IL-1b) and interleukin 6 (IL-6) are expressed post-natally in normal and tumoral cells in the anterior pituitary, and that they play a role in both the liberation of different hormones and in the growth, proliferation and tumor formation of the pituitary gland. However, their expression and role during embryonic and fetal development remain unknown. We have performed an immunocytochemistry study of prenatal expression and distribution of IL-1b and IL-6 in isolated embryonic rat Rathke's pouch prior to birth, more specifically between 13.5 and 19.5 days p.c. Western-blot analysis carried out on 19.5-day p.c. embryos showed positive immunolabelling for IL-1b and IL-6. These interleukins were initially expressed simultaneously in the rostral and ventral portions of Rathke's pouch in 15.5-day p.c. embryos, and this expression progressed caudodorsally in later developmental stages, extending to most of the hypophysis before birth. The number of cells expressing these interleukins increased throughout this period: 48.22% of anterior pituitary cells expressed IL-6 in 19.5-day embryos, whilst IL-1b was positive in 39.8% of the cells. Moreover, we have demonstrated that some adenohypophyseal cells co-express both interleukins. Such findings represent the first step towards an understanding of the physiological role of these interleukins in anterior pituitary development.

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Hypothalamus and cytodifferentiation of the foetal pituitary gland

Cited by 33 publications

References 9 publications

Morphine-induced stimulation of pituitary-adrenocortical activity is mediated by activation of nitric oxide in the early stages of postnatal life in the rat

Morphine-induced stimulation of pituitary-adrenocortical activity is mediated by activation of nitric oxide in the early stages of postnatal life in the rat

Postnatal development, sexual difference and sexual cyclic variation of prolactin cells in rats: Special reference to the topographic affinity to a gonadotroph.

Prenatal expression of interleukin 1β and interleukin 6 in the rat pituitary gland

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