Sexual dimorphism of the miniature pig submandibular glands

The submandibular salivary glands of 14 Pitman‐Moore miniature pigs were examined to determine whether they exhibit sexual dimorphism. Sections of the glands from seven male and seven female animals were stained by several histochemical methods. No morphological sex differences were noted in hematoxylin and eosin‐stained sections but differences were found with all of the histochemical methods utilized. Most noticeable was the higher concentration of sialic acid‐containing mucosubstances in mucous acini of the female submandibular gland sections when they were stained with either the Alcian blue (pH 2.5), Alcian blue (pH 2.5)‐periodic acid‐Schiff or periodic acid‐phenyl‐hydrazine‐Schiff methods. Unlike mucous acini, demilunes of the male submandibular gland possessed a higher concentration of sialic acid‐containing mucosubstance than did those of the female. The miniature pig, unlike other animal orders studied, possesses sexual dimorphism at three weeks of age, thus differing markedly from other animals in which sexual dimorphism of the salivary glands does not occur until after the onset of puberty.