Leptin gene expression in the hypothalamus and pituitary of pregnant pigs.

BACKGROUND: Leptin, the 16-kDa peptide hormone product of the ob gene, is a regulatory hormone secreted mainly by adipose tissue. Recent studies have shown leptin production by other tissues, including rat hypothalamus, rat and human pituitary, rat skeletal muscle, kidney and stomach, human and porcine placenta, human mammary epithelial cells as well as endometrial tissues. This hormone is a central modulator of food intake, metabolism and neuroendocrine functions.

OBJECTIVES: The aim of the study was to detect and locate porcine leptin gene expression in the different areas of the hypothalamus and pituitary on days 14-16 and 30-32 of pregnancy in pigs.

METHOD: Leptin gene expression was analysed by RT-PCR method. PCR products were subjected to sequencing analysis.

RESULTS: Leptin mRNA was expressed in the medial basal hypothalamus, preoptic area, stalk median eminence, anterior pituitary, posterior pituitary and adipose tissue on days 14-16 and 30-32 of pregnancy. Sequence analysis of the 258 bp product from the hypothalamus and pituitary confirmed 99% homology with the corresponding region of porcine leptin cDNA sequence.

CONCLUSION: Leptin mRNA expression in the porcine hypothalamus and pituitary gland implies its paracrine and/or autocrine role in the regulation of hypothalamic-pituitary axis activity.