[Comparison of the intraspecific growth of the endocranial organs (hypophyseal lobes, pineal gland, SFO) in the white Wistar rat. Rattus norvegicus (Berkenhout), with their interspecific growth in the rodents]

Abstract

The intraspecific growth of various endocranian organs (hypophysis, pineal gland and SFO) in the Rat compared to a group of Rodents shows that their allometry coefficient/somatic weight is : close to isometry for the anterior and intermediate lobes of the hypophysis which is suitable for endocrine glands; lower and close to that found for the relation brain weight/somatic weight for the nervous lobe in the Rat and in Rodents; and extremely low (0,33) for the SFO in the Rat, which is comparable to that found in Rodents (0,44). The allometry coefficient found for the pineal gland is not comparable to that found in Rodents (1,25). Many facts (important intra and interspecific variations, existence of species or individuals deprived of pineal gland) seem to indicate that this gland is not related to an essential somatic function.