Pituitary-G0nad Interaction in Immature Female Parabiotic Rats1

Meyer, Roland K.; Biddulph, Clyde; Finerty, John C.

doi:10.1210/endo-39-1-23

Cited by 15 publications

(5 citation statements)

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“…The procedure was initially developed at the end of the nineteenth century to test the viability of skin grafts [1]. Its utility as a model for investigating the role of circulating factors in the regulation of physiologic responses was soon recognized (see [2]) and parabiosis has since been used in the study of many different systems including reproduction [3–4], diabetes [5], aging [6], pituitary function [7], immune function [8] and stem cell biology [9]. …”

Section: 1 Introductionmentioning

confidence: 99%

Contribution made by parabiosis to the understanding of energy balance regulation

Harris

2013

Biochimica et Biophysica Acta (BBA) - Molecular Basis of Diseas

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Parabiosis is a chronic preparation that allows exchange of whole blood between two animals. It has been used extensively to test for involvement of circulating factors in feedback regulation of physiological systems. The total blood volume of each animal exchanges approximately ten times each day, therefore, factors that are rapidly cleared from the circulation do not reach equilibrium across the parabiotic union whereas those with a long half-life achieve a uniform concentration and bioactivity in both members of a pair. Involvement of a circulating factor in the regulation of energy balance was first demonstrated when one member of a pair of parabiosed rats became hyperphagic and obese following bilateral lesioning of the ventromedial hypothalamus. The non-lesioned partner stopped eating, lost a large amount of weight and appeared to be responding to a circulating “satiety” factor released by the obese rat. These results were confirmed using different techniques to induce obesity in one member of a pair. Studies with phenotypically similar ob/ob obese and db/db diabetic mice indicated that the obese mouse lacked a circulating signal that regulated energy balance, whereas the diabetic mouse appeared insensitive to such a signal. Positional cloning studies identified leptin as the circulating factor and subsequent parabiosis studies confirmed leptin’s ability to exchange effectively between parabionts. These studies also suggest the presence of additional unidentified factors that influence body composition.

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Section: 1 Introductionmentioning

confidence: 99%

Contribution made by parabiosis to the understanding of energy balance regulation

Harris

2013

Biochimica et Biophysica Acta (BBA) - Molecular Basis of Diseas

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“…Or what about the endocrine signaling between rats subjected to parabiosis experiments? 19 Or what about the endocrine signaling in conjoined twins? 20 Why are these still considered endocrine signaling?…”

Section: Is Oxygen An Endocrine Signal or Not?mentioning

confidence: 99%

Arguments for gasocrine signaling

Anbalagan

2023

Preprint

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In cellular signaling, a cell can send specific signals to another cell with a clear intention. The sent signals are sensed by the receiving cell, triggering a cellular response. If these sender and receiver cells are in direct physical proximity, the signaling is labeled as paracrine. If these cells are far and the signal is transported, the signaling is labeled as endocrine. In this manuscript, as others have argued in the past, I also argue that gasotransmitters must not be excluded as endocrine signaling molecules. I argue that, like LEGO bricks that can be built, dismantled, and rebuilt into anything of the builder's imagination, gasotransmitters are also LEGO bricks of endocrine signaling. I argue that we must bend the rules of definitions in endocrine signaling to incorporate gasotransmitter-based endocrine signaling, which I call gasocrine signaling. If the reason that oxygen is not considered an endocrine molecule is based on the fact that it does not satisfy the definition of signal – ‘signal is something that passes from a sender to a receiver that carries a ‘specific’ message’, then I argue that the ‘message’ is simply ‘live’ or ‘die’, depending on whether the organism is aerobe or anaerobe, respectively. I argue that HIFα is the receptor for oxygen. Gasocrine signaling, I propose, is our Earth’s equivalent of Na’vi’s connection with the ecosystem of Pandora in the movie Avatar.

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“…For example, involvement of pituitary factors in the control of gonadal hormone secretion was demonstrated when one member of a parabiosed pair of rats of was ovariectomized (Meyer, Biddulph, & Finerty, 1946). The resultant loss of negative feedback control stimulated release of the relatively stable gonadotrophin which was carried into the intact partner.…”

Section: The Parabiotic Modelmentioning

confidence: 99%

“…The ovaries of the partner enlarged in response to the stimulation, but estrogen from this animal had a short half-life in the circulation and failed to suppress secretion of the gonadotrophin in the ovariectomized rat. Estradiol injections into the ovariectomized rat led to the normalization of ovaries in the intact partner (Meyer, Biddulph, & Finerty, 1946). Thus, the presence of a feedback control system was demonstrated by the system “running-away” once there was a break in the feedback loop.…”

Section: The Parabiotic Modelmentioning

confidence: 99%

Is leptin the parabiotic “satiety” factor? Past and present interpretations

Harris

2013

Appetite

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In 1959 Hervey hypothesized that a circulating feedback signal informed the hypothalamus of the size of fat stores and initiated appropriate corrections to energy balance. The hypothesis resulted from a parabiosis study in which one animal became obese following lesioning of the ventromedial hypothalamus. The partner of the lesioned rat was hypophagic and lost a large amount of body fat. Similar results came from parabiosis studies with obese Zucker rats and rats that overate due to stimulation of the lateral hypothalamus. In studies in which one parabiont was made obese by overfeeding the non-overfed partners lost substantial amounts of fat with a minimal reduction in food intake and no loss of lean tissue. The loss of fat was due to inhibition of adipose lipogenesis and other metabolic adjustments typical of food restriction. Parabiosis with genetically obese mice implied that ob/ob mice did not produce the feedback signal and subsequently the mutant ob protein, leptin, was identified. This paper provides a review and interpretation of parabiosis work that preceded the discovery of leptin, an evaluation of leptin in relation to its function as the circulating feedback signal and evidence for additional circulating factors involved in the control of adipose tissue mass.

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Pituitary-G0nad Interaction in Immature Female Parabiotic Rats1

Cited by 15 publications

References 0 publications

Contribution made by parabiosis to the understanding of energy balance regulation

Contribution made by parabiosis to the understanding of energy balance regulation

Arguments for gasocrine signaling

Is leptin the parabiotic “satiety” factor? Past and present interpretations

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