[Sex, gender and stature: From biology to culture - and back]. / Sexe, genre et stature - De la biologie à la culture - et retour.

The origin of sexual dimorphism of stature (SSD) in the human species is a subject of debate, likely to have a sociocultural impact. Stature is optimally expressed in good environmental conditions, notably good food, with a strong hereditary determinism. The common academic interpretation, already proposed by Darwin, is that SSD results from sexual selection of stronger males, in most species of mammals, including humans. An alternative hypothesis proposes that it might result from alimentary gender coercion in humans. There is practically no SSD until female growth stops, by ossification of cartilage in the growth plates of long bones, largely under the action of estrogens. The mechanism is the same in males, with a delay due to a lesser and/or later concentration of estrogens. This explanation for SSD has the advantage of being valid for most mammalian species, including those like Pan paniscus where females are dominant. The fitness resulting from high estrogen levels would explain the relatively small stature of women, in spite of obstetric difficulties inversely correlated with height. If patriarchy is involved, it would be by the injunction of fertility rather than by alimentary coercion.

Title: Sexe, genre et stature - De la biologie à la culture - et retour. Abstract: Dans l'espèce humaine, l'origine du dimorphisme sexuel de stature est l'objet de controverses. Sa composante héréditaire pourrait dépendre principalement du déterminisme endocrinien de l'arrêt de croissance à la puberté. C'est l'explication la plus simple, une explication qui apparaît également valable pour la plupart des mammifères. L'ossification des cartilages de conjugaison, qui signe l'arrêt de croissance des os longs, se produit d'abord chez les femelles (les jeunes femmes) puis chez les mâles. Dans les deux sexes, elle reste contrôlée par l'augmentation du taux d'œstrogènes. L'avantage reproductif conféré par les œstrogènes permettrait d'expliquer la relativement petite taille des femmes, en dépit des difficultés obstétriques associées à cette petite taille.

Immunocytochemical analysis of rat vagus nerve by antibodies against glycogen phosphorylase isozymes.

Glycogen is an endogenous store of glucose equivalents for energy metabolism in many tissues. The brain contains a significant amount of glycogen the role of which as an energy reserve is currently under debate. Apparently little is known concerning a possible role of glycogen in peripheral nerves. We have demonstrated immunocytochemically the presence of glycogen phosphorylase (GP), a key enzyme in glycogen metabolism, in large and small axons of the rat vagus nerve, but not in Schwann cells. Furthermore, the isozyme-specific antibodies applied detected only the presence of the brain isoform BB of GP, but not the muscle isoform MM. This is in agreement with the occurrence of solely the BB isoform in the few brain and spinal cord neurons that contain GP. In contrast, astroglial cells in brain and spinal cord have previously been shown to contain both isoforms. Since GP isozymes are regulated differentially, the expression of isoform BB may provide hints to possible functions of glycogen in the vagus nerve.