Short-term but not long-term high-fat diet induces an increase in gene expression of gonadotropic hormones and GPR120 in the male mouse pituitary gland

Abstract

High-fat diet (HFD) is associated with the regulation of reproductive functions. This study aimed to investigate the effects of short-term HFD on the mRNA expression levels of follicle-stimulating hormone β subunit (FSHβ), luteinizing hormone β subunit (LHβ), gonadotropin-releasing hormone receptor, and long-chain fatty acid receptor, GPR120, in the matured male mouse pituitary gland. Adult male mice were fed either control chow or HFD for 1, 2, 5, 10, 30 and 150 days. Fshb and Gpr120 mRNA expression levels in the pituitary glands were significantly increased during 2 to 30 days of HFD feeding. Gnrh-r mRNA in the 30 days HFD fed group and body weight in the 30 and 150 days HFD fed groups were higher than control. However, there were no significant differences in plasma non-esterified fatty acids or glucose levels during the 150 days of HFD feeding. These results suggest that male mice feeding a short-term HFD induces FSHβ synthesis and GPR120 expression in their pituitary gonadotropes.

Estradiol production of granulosa cells is unaffected by the physiological mix of nonesterified fatty acids in follicular fluid

“…Since the estradiol synthesis of GCs was not affected by the coincident presence of saturated and unsaturated NEFAs, we wondered whether the implied NEFA-induced subfertility could be due to the reduced production of gonadotropin hormones such as FSH and LH, which are synthesized by the anterior pituitary gland and essential for the ovarian follicle development. An interesting study evaluating the effect of a high-fat diet on the pituitary expression of FSHB and LHB genes revealed no significant impact on the expression of these genes (protein expression data were not presented in the study), indicating NEFAs may not regulate the pituitary gonadotropin production ( 53 ). Alternatively, another critical component that could determine the regulation of the ovarian cycle is oocyte maturation and health.…”

<i>Gpr120</i> mRNA expression in gonadotropes in the mouse pituitary gland is regulated by free fatty acids

“…Unsaturated LCFAs downregulated the transcription of the rat Fshb gene [12] and mouse Fshb mRNA expression [31] in LβT2 cells. Short-term high-fat diets induced an increase in Fshb mRNA expression in adult male mice [13]. Furthermore, it has been established that the ERK1/2 pathway is located downstream of GPR120 to regulate several physiological functions such as GLP-1 secretion [2] and cytosolic phospholipase A2 activation [32].…”

“…However, the LCFA agonist GW9508 did not affect luteinizing hormone (LH) secretion [11] or the transcription of gonadotropin subunit genes [12] in an LβT2 gonadotropic cell line. Nevertheless, not only fasting but also short-term high fat diet feeding for just 2 days induced an increase in Gpr120 mRNA expression in the mouse pituitary gland [9,13], suggesting that GPR120 is sensitive to peripheral fatty acid levels and could function as a lipid sensor in pituitary gonadotropes.…”