Effects of infantile thymectomy on ovarian functions and gonadotrophin-induced ovulation in prepubertal mice: role of thymulin

García, Lorena; Hinojosa, Lorena; Domı́nguez, Roberto; Chavira, Roberto; Rosas, Patricia

doi:10.1677/joe.0.1660381

Cited by 21 publications

(17 citation statements)

References 13 publications

(14 reference statements)

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“…In young rats, TF5 inhibits TSH effect. Thymulin treatment in mice resulted in an earlier onset of puberty [43].…”

Section: Effect Of Thymic Self-hormones On Non-immune Cells and Functmentioning

confidence: 98%

The Immunoendocrine Thymus as a Pacemaker of Lifespan

Csaba¹

2016

Acta Microbiologica et Immunologica Hungarica

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The thymus develops from an endocrine area of the foregut, and retains the ancient potencies of this region. However, later it is populated by bone marrow originated lymphatic elements and forms a combined organ, which is a central part of the immune system as well as an influential element of the endocrine orchestra. Thymus produces self-hormones (thymulin, thymosin, thymopentin, and thymus humoral factor), which are participating in the regulation of immune cell transformation and selection, and also synthesizes hormones similar to that of the other endocrine glands such as melatonin, neuropeptides, and insulin, which are transported by the immune cells to the sites of requests (packed transport). Thymic (epithelial and immune) cells also have receptors for hormones which regulate them. This combined organ, which is continuously changing from birth to senescence seems to be a pacemaker of life. This function is basically regulated by the selection of self-responsive thymocytes as their complete destruction helps the development (up to puberty) and their gradual release in case of weakened control (after puberty) causes the erosion of cells and intercellular material, named aging. This means that during aging, self-destructive and non-protective immune activities are manifested under the guidance of the involuting thymus, causing the continuous irritation of cells and organs. Possibly the pineal body is the main regulator of the pacemaker, the neonatal removal of which results in atrophy of thymus and wasting disease and its later corrosion causes the insufficiency of thymus. The co-involution of pineal and thymus could determine the aging and the time of death without external intervention; however, external factors can negatively influence both of them.

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“…In young rats, TF5 inhibits TSH effect. Thymulin treatment in mice resulted in an earlier onset of puberty [43].…”

Section: Effect Of Thymic Self-hormones On Non-immune Cells and Functmentioning

confidence: 98%

The Immunoendocrine Thymus as a Pacemaker of Lifespan

Csaba¹

2016

Acta Microbiologica et Immunologica Hungarica

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“…In these mice, daily injection of thymulin, starting immediately after thymectomy treatment, results in normal puberty onset, estradiol serum levels and an induced ovulation ratio [5] .…”

Section: Effects Of Injecting Thymulin Into the Anterior Or Medial Hymentioning

confidence: 99%

Effects of Injecting Thymulin into the Anterior or Medial Hypothalamus or the Pituitary on Induced Ovulation in Prepubertal Mice

García¹,

Hinojosa²,

Domı́nguez³

et al. 2005

Neuroimmunomodulation

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In prepubertal mice, subcutaneous thymulin injection before equine chorionic gonadotrophin (eCG) treatment simulates ovulation; seemingly, the thymulin could be acting at the hypothalamus-pituitary axis level. Objective: This study was designed to analyze the effects of injecting thymulin into the hypothalamus or pituitary on induced ovulation of prepubertal mice. Method: Female mice, 19 days old, were anesthetized with ether and injected with saline solution or thymulin into the anterior or medial hypothalamus or the pituitary and treated with eCG when 20 days old. The ova shed were counted and serum concentrations of 17β-estradiol were measured. In the ovaries, the morphometrical analysis was performed and the atresia evaluated. Results: Ether anesthesia treatment blocked eCG-induced ovulation in almost all animals. Mice anesthetized and treated with eCG and gonadotrophin-releasing hormone (GnRH) or human chorionic gonadotrophin (hCG) ovulated a full quota of ova. Injecting saline solution into the anterior or medial hypothalamus or the pituitary did not reduce the blocking effects of ether anesthesia on induced ovulation, but the incidence of atretic follicles was higher. Injecting thymulin directly into the anterior hypothalamus did not restore ovulation, nor diminish the number of atretic follicles. In contrast, injecting thymulin into the medial hypothalamus restored the ovulation ratio and decreased the percentage of atretic follicles. Similar results were obtained by injecting thymulin into the pituitary, though thymulin treatment in the pituitary resulted in a higher number of ova shed and lower follicular atresia. Conclusion: The present results suggest that thymulin acts at the medial hypothalamus level, facilitating the release of GnRH and at the pituitary level regulating gonadotrophin release.

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“…Besides, production and secretion of thymulin is directly or indirectly influenced by the neuroendocrine system and there is hypophysiotropic activity [Goya et al, 2004] . Recent evidence suggests that thymulin plays a particularly relevant role in the hypothalamo-pituitary-ovarian axis in rodents [García et al, 2000;Hinojosa et al, 2004;García et al, 2005]. Interestingly, congenitally athymic (nude) mice display a number of deficiencies consistent with their lack of circulating thymic hormones (i.e.…”

Section: Introductionmentioning

confidence: 99%

Morphometric Assessment of the Impact of Serum Thymulin Immunoneutralization on Pituitary Cell Populations in Peripubertal Mice

Camihort¹,

Luna²,

Vesenbeckh

et al. 2006

Cells Tissues Organs

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Thymulin is a thymic hormone involved in several aspects of intra- and extrathymic T-cell differentiation. Thymulin also possesses hypophysiotropic activity which suggests that this metallopeptide may play an important role in thymus-pituitary communication, particularly during early life. The aim of the present study was to evaluate the impact of serum thymulin suppression from birth to peripuberty on the morphology of different pituitary cell populations in prepubertal C57Bl/6 mice. Animals were submitted to immunoneutralization of circulating thymulin from postnatal day 1 to the end of the study (age 32 days). From their 1st day of life, the animals were submitted to a protocol of intraperitoneal injections of rabbit anti-thymulin serum (α-FTS) and normal rabbit serum (NRS) in the controls. On their 33rd day of life, the animals were killed and their pituitaries were immediately dissected, fixed and immunostained using the EnVision system with primary antibodies against growth hormone, thyrotropin, corticotropin, gonadotropins and prolactin. Morphometry was performed by means of an image analysis system. The following parameters were calculated: volume density = Σ cell area/reference area (RA); cell density (CD) = number of cells/RA, and cell size (expressed in µm²). Serum thymulin was measured by a rosette bioassay while pituitary hormones were assayed by radioimmunoassay. Serum prolactin, luteinizing hormone, follicle-stimulating hormone, growth hormone and thyroid-stimulating hormone were significantly lower in the α-FTS animals of either sex compared with the corresponding NRS counterparts. The somatotrope, lactotrope and corticotrope populations showed a significant decrease in CD, while cell hypertrophy was observed in some of the pituitary cell populations of the α-FTS group compared to the NRS group. In the α-FTS group, there were sex differences in the morphometric changes observed. Our results suggest that serum thymulin plays a significant role during early life in the postnatal maturation of endocrine cells of the mouse anterior pituitary gland.

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Effects of infantile thymectomy on ovarian functions and gonadotrophin-induced ovulation in prepubertal mice: role of thymulin

Cited by 21 publications

References 13 publications

The Immunoendocrine Thymus as a Pacemaker of Lifespan

The Immunoendocrine Thymus as a Pacemaker of Lifespan

Effects of Injecting Thymulin into the Anterior or Medial Hypothalamus or the Pituitary on Induced Ovulation in Prepubertal Mice

Morphometric Assessment of the Impact of Serum Thymulin Immunoneutralization on Pituitary Cell Populations in Peripubertal Mice

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