Expression and thyroid hormone regulation of annexins in the anterior pituitary

Abstract

Due to their property to bind to phospholipids in a Ca 2C -dependent manner, proteins of the annexin superfamily are involved in many membrane-related events and thus in various forms of physiological and pathological processes. We were therefore interested in analyzing the mRNA expression of the annexins in the severely disorganized pituitaries of the athyroid Pax8 K/K mice in comparison with that of control animals. In neither condition was mRNA expression of the annexins A3, A7, A8, A9, A11, and A13 detectable. The annexins A2, A4, and A6 were equally expressed in wild-type and Pax8 K/K mice. Transcript levels of A1 and A10 were highly increased and those of A5 were significantly decreased in the athyroid mutants compared with controls. Treatment of Pax8 K/K mice with physiological doses of thyroxine for 3 days normalized the mRNA expression of A1, A5, and A10 indicating that the expression of these annexins is directly regulated by thyroid hormone (TH). Since A5 exhibits by far the highest transcript levels of all annexins in the pituitary and its regulation by TH could be also confirmed at the protein level, we analyzed the mRNA expression of pituitary hormones in A5 K/K mice. In these mutants, only the b-FSH mRNA expression was found to be significantly reduced, while the mRNA expression levels of the other pituitary hormones were not altered. These results support the concept that annexins might serve important albeit redundant functions as modulators of pituitary hormone secretion.

New Approach for M-Cell-Specific Molecules Screening by Comprehensive Transcriptome Analysis

“…14,15 Although annexin A10 is implicated in regulating hepatocyte differentiation 16 and pituitary hormone synthesis and/or secretion, 17 the molecular basis for its function remains unclear.…”

Immunohistochemical Localization of Annexin A5 in the Mammary Gland of Rats: Up-Regulation of Expression by Pup Removal

“…However, its physiological relevance is not well understood. An annexin A5 knock-out mouse has been established, but no distinct phenotype has been reported [2,15]. We have revealed that annexin A5 is involved in GnRH stimulation of gonadotropin secretion [11].…”

Proteome and radioimmunoassay analyses of pituitary hormones and proteins in response to feed restriction of dairy cows

“…An additional annexin A5 spot (spot 156, Supporting Information Table 1) was identified at the same MW as spot 6 and 7 indicating that annexin A5 occurs with different PTM. Although it is known that annexin A5 inhibits PRL release 45 and annexin A5 synthesis is enhanced in the presence of TH, gonadotropin releasing hormone, or after ovariectomy 46, a link directly referring to feed intake has not been reported so far. Also, secretogranin V (neuroendocrine polypeptide 7B2) is involved in the hormone secretion process.…”