Expression of Adiponectin and Adiponectin Receptors in Human Pituitary Gland and Brain

Abstract

Background/Aims: Adiponectin and its receptors, AdipoR1 and AdipoR2, constitute integral components of energy homeostatic mechanism in peripheral tissues. Recent studies have implicated adiponectin in central neural networks regulating food intake and energy expenditure. The present study aimed at investigating the possible expression and distribution of adiponectin and its receptors in human pituitary gland, hypothalamus and different brain areas. Methods: Sections of the pituitary gland, hypothalamus and adjacent basal forebrain area, cerebrum and cerebellum from 35 autopsy cases, were examined using HE, PAS-Orange G, luxol fast blue/cresyl violet stains and single and double immunohistochemistry using adiponectin, AdipoR1, AdipoR2, choline acetyltransferase, FSH, LH, TSH, GH, ACTH and prolactin-specific antibodies. Age and BMI mean values ± SD of the autopsy cases were 56 ± 18 years and 27 ± 5 kg/m², respectively. Results: Strong adiponectin expression was observed in pituitary gland. In pars distalis (PD), adiponectin localized in GH, FSH, LH and TSH-producing cells and in pars tuberalis (PT) in FSH, LH and TSH-producing cells. Strong to moderate expression of AdipoR1 and AdipoR2 was observed in PD by the same cell types as adiponectin. No immunoreactivity for adiponectin receptors was noted in cells of PT. Intense AdipoR1 immunostaining was observed in neurons of lateral hypothalamic area and of nucleus basalis of Meynert (NBM). Conclusions: Adiponectin and its receptors expression in human pituitary might indicate the existence of a local system, modulating endocrine axes. Furthermore, the presence of AdipoR1 in hypothalamus and NBM suggests that adiponectin may participate in central neural signaling pathways controlling energy homeostasis and higher brain functions.

Role of genetic variants in ADIPOQ in human eating behavior

“…All analyses were standardized to the minor allele ADIPOQ locus and eating behavior Beside its well-described role in endocrine metabolism and cardiovascular function in peripheral tissues as well as the reported autocrine effects on adipocytes (Wu et al 2003), adiponectin confers also central effects on energy expenditure or food intake (Kubota et al 2007;Qi et al 2004;Kadowaki et al 2008). It was recently shown that adiponectin is also expressed in brain (Rodriguez-Pacheco et al 2007;Psilopanagioti et al 2009) and is functionally active (Rodriguez-Pacheco et al 2007). In addition, several studies reported intracerebral injection (Hoyda et al 2009a;Iwama et al 2009;Park et al 2011) and most importantly expression of adiponectin receptors in the brain (Hoyda et al 2009b;Dadson et al 2011).…”

Brain Activation by Visual Food-Related Stimuli and Correlations with Metabolic and Hormonal Parameters: A fMRI Study

“…Lately it has been shown to be of importance to categorize the visual food stimuli in low versus high calorie stimuli as this could influence the results especially during the fasting state [47]. Also, recently published data have implicated adiponectin in regulating food intake and energy expenditure [48,49]. Moreover, glucagon-like peptide-1 (GLP-1), which is synthesized in the brain as well [50,51], may also be involved.…”

Adiponectin protects rat hippocampal neurons against excitotoxicity

“…Expression of AdipoR1 and AdipoR2 was observed in hippocampal neurons in mice, GT1-7 cell line derived from mouse hypothalamic neurons in rat, and the pituitary, nucleus basalis and hypothalamus in humans (Jeon et al 2009;Wen et al 2008;Guillod-Maximin et al 2009;Psilopanagioti et al 2009). Adiponectin-knockout mice exhibit enlarged brain infarction and increased neurological deficits after ischemia reperfusion compared to wild-type mice, while adenovirus-mediated supplementation of adiponectin significantly reduces cerebral infarct size in both wild-type and adiponectin-deficient mice (Nishimura et al 2008), suggesting that adiponectin may have neuroprotective activity.…”