Maturation of the Inhibitory Response of Growth Hormone Secretion to Ether Stress in Postnatal Rat

Štrbák, Vladimír; Jurcovicová, J; Vigaŝ, M

doi:10.1159/000124101

Cited by 7 publications

(1 citation statement)

References 9 publications

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“…fn the present study, the a2-adrenergic antagonist YOH prevented the nursing-induced increase in serum GH levels in two-and eight-day-old pups, suggesting that the nursing-induced increase in serum GH might be similarly mediated via the a2-adrenergic-rGHRH pathway. The wall-climbing-like behavioral effects of these drugs may be viewed as the sign of stress; stress is known to inhibit GH secretion via the activation of somatostatin (SRfF) in adult and in three-day-old rats (22)(23)(24). The lack of an additive effect between CLO and nursing in 10-day-old male pups might alterna¬ tively be explained with an inhibition of the nursinginduced GH secretion (an effect present in the females) plus a GH-releasing effect via the a2-GHRH system (a mechanism previously demonstrated in 10-day-old male pups).…”

Section: Discussionmentioning

confidence: 99%

Interaction between the α2-adrenergic system and nursing in the regulation of growth hormone secretion in the neonatal rat

Kacsóh

Js²,

Wr³

et al. 1993

Acta Endocrinologica

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Kacsóh B, Opp JS, Crowley WR, Grosvenor CE. Interaction between the a2-adrenergic system and nursing in the regulation of growth hormone secretion in the neonatal rat. Acta Endocrinol 1993;128:184-91. ISSN 0001-5598 Separation of neonatal rats from their mothers decreases, while a subsequent period of suckling (nursing) increases, serum growth hormone (GH) levels in neonatal rats. Milk-borne (humoral) factors and neural factors inherent in mother-offspring interaction have been implicated in these phenomena. Conflicting reports have demonstrated the \g=a\2-adrenergic agonist clonidine to increase and to decrease serum GH levels in 10-day-old rats. The present experiments were aimed at testing whether an interaction between the \g=a\2-adrenergic system and the nursing-induced changes in GH secretion could account for the discrepancy. Rat pups were treated with clonidine (150 \g=m\g/kg) or the \g=a\2-adrenergic antagonist yohimbine (10 mg/kg), and the drug treatment was combined with separation of the mothers and nursing. Yohimbine did not affect serum GH levels in separated two-day-old pups (i.e. basal levels of the hormone), but prevented the nursing-induced increase in serum GH concentration. In twoday-old pups, clonidine had no effect on basal GH levels but, like yohimbine, prevented the increase in serum GH normally associated with nursing. Both yohimbine and clonidine prevented active sucking behavior, i.e. the pups did not search for and/or attach to the nipples of their mothers. Moreover, the pups treated with yohimbine and clonidine were cooler to the touch than the littermate controls. In eight-day-old pups, yohimbine prevented the nursing-induced increase in serum GH and decreased GH levels below the saline-injected, separated control. As in two-day-old pups, clonidine prevented the suckling-induced release of GH and failed to induce GH-release above that of saline-injected, separated pups. By day 10 postpartum. clonidine became capable of stimulating GH release, but only in separated male pups. The effects of CLO and nursing in male pups were not additive: either treatment alone was as

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Section: Discussionmentioning

confidence: 99%

Interaction between the α2-adrenergic system and nursing in the regulation of growth hormone secretion in the neonatal rat

Kacsóh

Js²,

Wr³

et al. 1993

Acta Endocrinologica

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The Growth Hormone Secretory Pattern and Statural Growth

Robinson¹,

Hindmarsh

1999

Comprehensive Physiology

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The sections in this article are: How is the Growth Hormone Secretory Pattern Analyzed? General Considerations in Pulse Analysis of Growth Hormone Secretion Construction of Data Arrays or Hormone Profiles Sampling Interval and Aliasing Duration of Sampling Discrete or Integrated Samples Assays and Noise Basic Evaluation Stationarization Analysis of Profiles Time Series Analysis Deconvolution Analysis Baseline Occupancy Chaos Neural Networks Characterization of Growth Hormone Secretory Patterns Ontogeny of Episodic Growth Hormone Secretion Growth Hormone Secretory Patterns in the Prepubertal Period Puberty and Effects of Gonadal Steroids on the Growth Hormone Secretory Pattern Growth Hormone Secretory Patterns in Adulthood Other Endocrine Inputs Affecting Growth Hormone Secretory Patterns Extrinsic Factors Affecting Growth Hormone Pulsatility How Does the Growth Hormone Secretory Pattern Reflect the Episodic Nature of Hypothalamic Control Mechanisms? Growth Hormone–Releasing Hormone and Somatostatin Interactions Generate Growth Hormone Pulsatility Other Growth Hormone Secretogogues Growth Hormone Feedback Effects on Endogenous Growth Hormone Pulsatility How is The Growth Hormone Secretory Signal Modified in its Passage from the Pituitary to the Peripheral Target Tissues? How Are Growth Hormone Patterns Modified by Interactions with Growth Hormone Binding Proteins? How are the Temporal Elements of the Growth Hormone Signal Detected and Interpreted by the Target Tissues? Pattern‐Dependent Growth Hormone Responses Growth Hormone Patterns and Insulin‐Like Growth Factor I Generation What is the Significance of the Growth Hormone Secretory Pattern for Statural Growth? Animal Studies Human Studies Indirect Manipulation of Growth Hormone Secretory Pattern Summary

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Fetal development and regulation of pituitary cell types

Dubois

Hemming

1991

J. Elec. Microsc. Tech.

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The ontogenesis of the pituitary gland is considered from anatomical and functional points of view. Embryogenesis of the hypothalamo-pituitary unit involving development of the hypothalamo-hypophyseal portal system is complete during early life as shown in several mammalian species. The ultrastructural characteristics of the different cell types during development are described according to observations made by using immunochemical techniques. The patterns of differentiation of the cell types are reviewed according to studies of pituitary glands from human anencephalic fetuses and encephalectomized rat fetuses as well as in vitro studies of cultured pituitary primordia in synthetic media. The maturation of the neuroendocrine mechanisms controlling the secretion of fetal hormones is also analyzed. During fetal life, the factors implicated in the regulation of pituitary hormone secretion are generally the same as in adults, but the intensity of the response of pituitary cells to their action is variable according to the species, thus reflecting an immaturity in the functioning of certain cell types.

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Maturation of the Inhibitory Response of Growth Hormone Secretion to Ether Stress in Postnatal Rat

Cited by 7 publications

References 9 publications

Interaction between the α2-adrenergic system and nursing in the regulation of growth hormone secretion in the neonatal rat

Interaction between the α2-adrenergic system and nursing in the regulation of growth hormone secretion in the neonatal rat

The Growth Hormone Secretory Pattern and Statural Growth

Fetal development and regulation of pituitary cell types

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