Mathematical models applied to prenatal growth of the ovine pineal gland1

SUMMARY In order to obtain mathematical models applicable to prenatal growth of the ovine pineal gland, 420 embryos and fetuses at varying stages of development were used for morphometric analysis. For each of the following variables studied, results were expressed as mean ± standard error : body weight, head weight, brain weight, pineal gland weight and pineal gland volume. The possible influence of sex on variables was determined by analysis of variance. The set of variables analysed was fitted to mathematical growth models. The results obtained indicate that during prenatal development all the variables examined fit a curvilinear-multiplicative growth model; additionally, the increase in these weights exceeds increases in length, particularly in the case of the pineal gland, suggesting considerable prenatal development of the gland, especially at the perinatal stage, where there is a marked increase in both weight and volume. It’s also discussed the possible influence of morphologic changes of the pineal gland in its physiological maturation during prenatal development and it is established a clear correspondence between the different phases of the growing curves of the pineal gland whit the ontogenic-proliferative and hypertrophic-differentiative phases, previously described by the authors in their description of the ovine pineal gland development. Finally, the data presented are offered to the scientific community to be used on future researches (i.e. in order to obtain the value of the volume or weight of pineal gland using the curve and the formulae displayed in a specific phase of development).