Cadmium chronotoxicity at pituitary level: effects on plasma ACTH, GH, and TSH daily pattern

Abstract

Cadmium is an endocrine disruptor that has been shown to induce chronotoxic effects. The present study was designed to evaluate the possible cadmium effects on the daily secretory pattern of adrenocorticotropin hormone (ACTH), growth hormone (GH), and thyroid-stimulating hormone (TSH) in adult male Sprague-Dawley rats. For this purpose, animals were treated with cadmium at two different doses [25 and 50 mg/l cadmium chloride (CdCl(2))] in the drinking water for 30 days. Control age-matched rats received cadmium-free water. After the treatment, rats were killed at six different time intervals throughout a 24-h cycle. Cadmium exposure modified the 24-h pattern of plasma ACTH and GH levels, as the peak of ACTH content between 12:00 and 16:00 h in controls appeared at 12:00 h in the group treated with the lowest dose used, while it appeared between 16:00 and 20:00 h in rats exposed to 50 mg/l CdCl(2). In addition, the peak of GH content found at 04:00 h in controls moved to 16:00 h in rats exposed to 25 mg/l CdCl(2), and the highest dose used abolished 24-h changes of GH secretion. The metal treatment did not modify ACTH secretory pattern. Exposure to cadmium also increased ACTH and TSH medium levels around the clock with both doses used. These results suggest that cadmium modifies ACTH and TSH medium levels around the clock, as well as disrupted ACTH and GH secretory pattern, thus confirming the metal chronotoxicity at pituitary level.

Protective Effect of Montelukast against Cadmium Induced Pituitary Gland Toxicity

“…Group 2 received ML diluted in distilled water at a dose of 10 mg/kg/ day orally [13]. Group 3 received Cd at 3 mg CdCl 2 /kg/ day (50 mg/l CdCl 2 ) (this dose produces neuroendocrinal disruption) [14]. Group 4 received both ML plus Cd at a dosage like group 2 and 3.…”

Rat Strain and Housing Conditions Alter Oxidative Stress and Hormone Responses to Chronic Intermittent Hypoxia

“…Maintaining homeostatic HPA hormones is necessary in maintaining sleep architecture ( Karatsoreos et al, 2011 ; Machado et al, 2013 ). Corticosterone and ACTH fluctuate in diurnal patterns that mirror each other, with low concentrations occurring at the beginning of the sleep phase ( Chacon et al, 2005 ; Caride et al, 2010 ). Although our samples were collected during the nadir phase, the further suppression of HPA hormones as the AHI increased indicates CIH was a chronic stressor resulting in dysregulation of the HPA axis.…”

Linking Cigarette Smoking/Tobacco Exposure and Cluster Headache: A Pathogenesis Theory

“…28 In addition, it can also alter GH secretion and change GH circadian rhythmicity. 28,47 Both of these hormones have been linked to trigeminal autonomic cephalalgia-like headaches, including CH, suggesting their persistent or transient secretion from chronic cadmium/xenoestrogen exposure may be one of the priming sources for CH initiation or at least for brain sensitization. 30,48 They also may contribute to the circadian alterations CH patients go through during their lifetime.…”

“…37 In female rodents, estrogen tonically inhibits the expression of orexin, and estrogen replacement will normalize very elevated orexin levels in postmenopausal women. 28,47 Both of these hormones have been linked to trigeminal autonomic cephalalgia-like headaches, including CH, suggesting their persistent or transient secretion from chronic cadmium/xenoestrogen exposure may be one of the priming sources for CH initiation or at least for brain sensitization. 37 One could hypothesize that as cadmium is chronically estrogenizing the brain it may be tonically inhibiting orexin A production, thus setting the environment (along with its other secondary hypothalamic toxicity issues) to create a CH sensitive brain.…”