High‐Cholesterol Diet Disrupts the Levels of Hormones Derived from Anterior Pituitary Basophilic Cells

Abstract

Emerging evidence shows that elevated cholesterol levels are detrimental to health. However, it is unclear whether there is an association between cholesterol and the pituitary. We investigated the effects of a high-cholesterol diet on pituitary hormones using in vivo animal studies and an epidemiological study. In the animal experiments, rats were fed a high-cholesterol or control diet for 28 weeks. In rats fed the high-cholesterol diet, serum levels of thyroid-stimulating hormone (TSH; also known as thyrotrophin), luteinising hormone (LH) and follicle-stimulating hormone (FSH) produced by the basophilic cells of the anterior pituitary were elevated in a time-dependent manner. Among these hormones, TSH was the first to undergo a significant change, whereas adrenocorticotrophic hormone (ACTH), another hormone produced by basophilic cells, was not changed significantly. As the duration of cholesterol feeding increased, cholesterol deposition increased gradually in the pituitary. Histologically, basophilic cells, and especially thyrotrophs and gonadotrophs, showed an obvious increase in cell area, as well as a potential increase in their proportion of total pituitary cells. Expression of the β-subunit of TSH, FSH and LH, which controls hormone specificity and activity, exhibited a corresponding increase. In the epidemiological study, we found a similar elevation of serum TSH, LH and FSH and a decrease in ACTH in patients with hypercholesterolaemia. Significant positive correlations existed between serum total cholesterol and TSH, FSH or LH, even after adjusting for confounding factors. Taken together, the results of the present study suggest that the high-cholesterol diet affected the levels of hormones derived from anterior pituitary basophilic cells. This phenomenon might contribute to the pituitary functional disturbances described in hypercholesterolaemia.

Analysis of the correlation between lipotoxicity and pituitary-thyroid axis hormone levels in men and male rats

“…TSH includes α-subunit and β-subunit, and the β-subunit is responsible for TSH specificity and endows biological activity on TSH [9, 16, 17]. Thus, as we explored the effect of the HF diet on the TSH level, we directly evaluated the transcription of β-subunit.…”

“…Blood samples were obtained from all the subjects from 8:00 to 10:00 after a minimum 10-h overnight fast [9, 38, 39]. Serum TSH, FT3, FT4, FSH, LH, T, ACTH and COR levels were determined by chemiluminescent methods (Roche, Basel, Switzerland).…”

“…According to the manufacturer's instructions, the TG, TC and free cholesterol contents in the pituitary were extracted and measured with kits (Applygen, Beijing, China), and free fatty acids content were determined with a kit (BioVision, CA, USA) [9]. …”

“…Quantitative RT-PCR was carried out in accordance with a method previously described [9]. In brief, total RNA was extracted from pituitary with the RNeasy Kit (Qiagen, Canada).…”

“…The pituitary gland, a crucial neuroendocrine organ, synthesizes and secretes different kinds of pituitary hormones [9]. It also participates in controlling multiple endocrine organs.…”