Immunocytochemical localization of annexin 5, a calcium-dependent phospholipid-binding protein, in rat endocrine organs

Abstract

Annexin 5, a unique calcium- and phospholipid-binding protein, has been investigated for its specific distribution in rat endocrine organs by immunocytochemistry with a specific antiserum to recombinant rat annexin 5. Follicular epithelial cells and parafollicular cells of the thyroid gland, adrenocortical cells of the zona fasciculata and zona reticularis, luteal cells, testicular interstitial cells, and Sertoli cells were shown to contain annexin 5. To examine whether the synthesis of annexin 5 would be affected by a change in humoral signal, the distribution of annexin 5 in the anterior pituitary was examined three weeks after ovariectomy. The withdrawal of ovarian hormones induced huge castration cells in the anterior pituitary gland, which contained abundant annexin 5. Annexin 5 was not detected in the pineal gland, the parathyroid gland, the islet of Langerhans, the adrenal medulla, zona glomerulosa cells, and granulosa cells. Since annexin 5 was shown to exist in many of the endocrine tissues examined, to be localized in specific cell types, and to be abundant in castration cells, it is suggested that annexin 5 contributes to secretory cell functions, which may be common to endocrine cells secreting chemically different hormones.

Gonadotropin Releasing Hormone (GnRH) Enhances Annexin A5 mRNA Expression through Mitogen Activated Protein Kinase (MAPK) in L.BETA.T2 Pituitary Gonadotrope Cells

“…However, it is not known whether the phospholipid binding is physiologically relevant to some particular function. Our findings here, together with our previous results [6][7][8]52], suggest a role for annexin A5 in signal transduction in the gonadotropes. This idea is further supported by the results reported by other groups.…”

Intrauterine programming of fetal islet gene expression in rats?effects of maternal protein restriction during gestation revealed by proteome analysis

“…Annexin V could also be involved in the lower insulin secretion. It is a member of a calcium-dependent phospholipid-binding protein family, which participates in vesicular transport specifically in plasma membrane to membrane or plasma membrane to cytoskeleton interactions [74]. Likewise, nucleobindin 2 is a DNA-and calcium-binding protein, which is involved in establishing the agonistmobilisable Golgi Ca 2+ store, together with the sarcoplasmic and endoplasmic reticulum calcium ATPase (SERCA) and the inositol triphosphate 3 receptor (IP3R) [101].…”

Annexin 5 Inhibits Thyrotropin Releasing Hormone (TRH) Stimulated Prolactin Release in the Primary Culture of Rat Anterior Pituitary Cells

“…We found that annexin 5 distributes also in lactotropes and other pituitary cells [11,14], although the intensity is less than that of the gonadotropes and it has yet to be determined whether annexin 5 is synthesized in these cell species or not. Annexin 5 was shown to inhibit prolactin release, even though the degree of inhibition was not very high in primary pituitary cell cultures [14].…”

“…Although the biochemical properties of annexinfamily proteins suggest roles in significant cell functions, the function of these proteins in physiological processes is still obscure [7]. We previously demonstrated that annexin 5 is synthesized in the anterior pituitary gland [8] and later found that it is produced by pituitary gonadotropes under the regulation of gonadotropin releasing hormone (GnRH) [9][10][11][12][13]. As annexin 5 augments gonadotropin secretion in vitro [13] and antisense oligodeoxynucleotide to annexin 5 mRNA retards luteinizing hormone release by GnRH, annexin 5 is thought to mediate at least part of the action of GnRH on pituitary gonadotropes [13].…”