Influence of Photoinhibition on the Morphology and Function of Pituitary Lactotropes in Male Golden Hamsters

Cónsole, Gloria M.; Jurado, Susana Beatriz; Petruccelli, Miguel Ángel; Carino, Mónica Herminia; Calandra, Ricardo S.; Dumm, C.L.A. Gómez

doi:10.1159/000057341

Cited by 14 publications

(18 citation statements)

References 27 publications

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“…Morphometric studies were performed as previously reported in detail. 24 Briefly, measurements of adipocyte parameters were made with an image analysis system (Imaging Technology, Optimas 5.2). Each field of immunostained cells in the reference area (RA; area scanned where adipocytes were scored) was measured for an average of 10 micrographs taken from two levels (e.g.…”

Section: Animals and Treatmentmentioning

confidence: 99%

Impact of transient correction of increased adrenocortical activity in hypothalamo-damaged, hyperadipose female rats

et al. 2005

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Objective: To explore the effects of transient correction of enhanced corticoadrenal activity in monosodium L-glutamate (MSG)-damaged female rats on peripheral insulin sensitivity and in vitro retroperitoneal (RP) adipocyte function. Designs: A dose of 4 mg/g body weight (BW) of MSG or vehicle (CTR) was i.p. injected, once every 2 days, between days 2 and 10 of age, in female rats. Intact and 21 day-operated (sham or adrenal enucleation (AE)) rats from both (CTR and MSG) groups were used for experimentation on day 120 of age. Circulating levels of several hormones, in basal and after i.v. high-glucose load conditions, and RP adiposity morphology and function were then evaluated. Results: MSG rats developed increased adrenocortical function, hyperadiposity, hyperleptinemia, hyperinsulinemia and decreased peripheral insulin sensitivity. These characteristics were fully reversed after transient correction of corticoadrenal hyperactivity induced by AE. In addition, in vitro experimentation with isolated RP adipocytes indicated that cells from intact MSG animals displayed decreased sensitivity to insulin and dexamethasone stimulation of leptin secretion. Interestingly, adipocyte dysfunction in MSG rats was fully abrogated after AE-induced transient correction of insulinemia, leptinemia and adrenocortical activity. Importantly, the reversion of these metabolic abnormalities, induced by AE for 21 days, in MSG animals did occur, despite no significant changes in BW values. Conclusion: Our results support that the changes in adipocyte characteristics and peripheral insulin resistance, developed in this pseudo-obese female rat model, are mainly due to increased glucocorticoid production. Importantly, appropriate correction of the enhanced adrenocortical activity fully reversed these abnormal functions.

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Section: Animals and Treatmentmentioning

confidence: 99%

Impact of transient correction of increased adrenocortical activity in hypothalamo-damaged, hyperadipose female rats

et al. 2005

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“…Morphometry was performed as reported in detail previously [Cónsole et al, 2002]. Stated in brief, immunostained pituitary cells were assessed by means of an image analysis system (Imaging Technology, Optimas 5.2).…”

Section: Morphometrymentioning

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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“…Morphometry was performed as reported in detail previously [21]. Measurements of immunostained lactotrope cells were made by means of an image-analysis system (Imaging Technology, Optimas 5.2).…”

Section: Methodsmentioning

confidence: 99%

The Thymulin-Lactotropic Axis in Rodents: Thymectomy, Immunoneutralization and Gene Transfer Studies

Martines

Reggiani

Camihort³

et al. 2013

Neuroimmunomodulation

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Objectives: There is clear evidence on the existence of a thymus-pituitary axis which seems to be particularly important during perinatal life. In particular, the thymic peptide thymulin has been shown to be a relevant player in thymus-pituitary communication. Our goal was to explore the effect of thymulin on circulating prolactin (PRL) levels in different animal models. To this end we undertook a series of experiments in rats and mice, implementing adult thymectomy, thymulin immunoneutralization in normal C57BL/6 mice and neonatal thymulin gene therapy in nude mice. Methods: We assessed the impact of the above manipulations on PRL secretion and lactotrope morphology by measuring serum PRL by radioimmunoassay and by performing morphometric analysis of the lactotropic cell population in the anterior pituitary gland. Results: Adult thymectomy in female rats slightly increased serum PRL, an effect that was partially reversed by thymulin gene therapy. In mice, thymulin immunoneutralization from birth to age 32 days reduced serum PRL both in males and females. Thymulin immunoneutralization induced a significant (p < 0.01) decrease in lactotrope cell density (CD) and volume density (VD) without changes in cell size (CS). Neonatal thymulin gene therapy markedly increased serum thymulin (p < 0.01) and lactotrope CD, CS and VD in nude mice of both sexes. Conclusions: Our findings suggest a modulatory effect of thymulin on the lactotrope cell population and on serum PRL, particularly during early life.

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Influence of Photoinhibition on the Morphology and Function of Pituitary Lactotropes in Male Golden Hamsters

Cited by 14 publications

References 27 publications

Impact of transient correction of increased adrenocortical activity in hypothalamo-damaged, hyperadipose female rats

Impact of transient correction of increased adrenocortical activity in hypothalamo-damaged, hyperadipose female rats

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

The Thymulin-Lactotropic Axis in Rodents: Thymectomy, Immunoneutralization and Gene Transfer Studies

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