Hamster aphrodisin

Magert H., Cieslak A., Alkan O., Luscher B., et al. (1999). The golden hamster aphrodisin gene — stmcture, expression in parotid glands of female animals, and comparison with a similar murine gene. J Biol Chem 274, 444-450. 

Some sensory neurons of the VNO express two gene superfamilies, termed Vlr and V2r, that encode over 240 proteins of the seven-transmembrane type (Matsunami and Buck, 1997). These G-protein-linked putative pheromone receptors are distantly related to the main olfactory system s receptors. Receptors of the VNO are linked to different G-proteins, and their extracellular N-terminal domains are longer than those of the receptors in the main olfactory system. (Vi receptors are linked to Gi-proteins and V2 receptors to Go-proteins). The intracellular excitation mechanism in VNO sensory neurons also differs from that in the main olfactory systems instead of linking to adenylyl cyclase, the VNO receptors activate the phosphoinositol second messenger system. This has been demonstrated in several mammalian species. In hamsters, aphrodisin increases inositol 1,4,5-trisphosphate (IP3) levels in VNO membranes. Boar seminal fluid and urine stimulate increases of IP3 in the VNO of the female pig. (However, in the pig, the VNO is not necessarily essential for responses to pheromones [Dorries etal., 1997]). 

In support of this contention, the carrier protein Aphrodisin makes an early appearance in vaginal secretions. In pre-pubertal hamsters, it thus indicates chemosensory preparation for the onset of female maturity (Magert, 1999). The proven ability of the AOS to modulate the CNS-pituitary-gonadal axis by advancing or retarding endocrine activity (Chap. 5), underlines its role as primarily the chemosensor of the reproductive system. The adaptive consequence of responses, which allows an avoidance of premature breeding, or of a postponement of puberty, would seem to be advantageous. 

Briand L., Huet J., Perez V., Lenoir G., et al. (2000). Odorant and pheromone binding by aphrodisin, a hamster aphrodisiac protein. FEBS Letts 476, 179-185. 

Kruhoffer M., Bub A., Cieslak A., Adermann K., et al. (1997). Gene expression of aphrodisin in female hamster genital tract segments. Cell Tissue Res 287, 153-160. 

Singer A.G., Clancy A.N. and Macrides F. (1989). Conspecific and heterospecific proteins related to aphrodisin lack aphrodisiac activity in male hamsters. Chem Senses 14, 563-576. 

However, not all lipocalins need to complex a small ligand in order to fulfill their physiological role. In aphrodisin, for example, which acts as a strong pheromone on male hamsters, the polypeptide itself seems to be responsible for the biological activity, fhus requiring transfer of the non-volatile macromolecule by... 

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