A histochemical and biochemical study of the parotid gland in normal and hypophysectomized rats

Abstract

Ann. Arbor TWENTY FIGURESBaker and Abrams ( '55) demonstrated a marked reduction in weight of the parotid gland after hypophysectomy. Concurrently, the acinar cells became smaller, were depleted of zymogenic granules and their amylase content was reduced (Baker et al., '56). These observations suggest that maintenance of the normal structure and function of the parotid gland is dependent on the action of hormones.Additional interest in the relationship of the parotid gland to the endocrine system is created by the postulation that it is itself an endocrine organ. Ito ('54) and I t o and Okabe ('55) reported the chemical characteristics of a purified protein which they called parotin, that was extracted from the parotid gland of cattle and from human saliva. It was believed to be the salivary gland hormone described previously by Ogata (cited by Ito, '54). The following observations led to the theory that secretion of parotin mediates the action of pituitary growth hormone. The tibia1 epiphysis failed to respond to pituitary growth hormone in hypophysectomized-sialo-

Changing myoepithelial cell distribution during regeneration of rat parotid glands.

“…1980 ; Redman 1994). In adult rats only the intercalated ducts are surrounded by myoepithelial cells, which merely extend their processes onto adjacent acini ( Dewey 1958; Bogart 1971; Garrett & Emmelin 1979; Redman 1994). It was noticed that the period of myoepithelial cell decrease coincides with the weaning period ( Redman 1994).…”

“…During development of the rat parotid gland, myoepithelial cells appear at the periphery of not only intercalated ducts but also acini until the age of two weeks, then decrease at the latter site between 18 and 25 days (Redman et al 1980;Redman 1994). In adult rats only the intercalated ducts are surrounded by myoepithelial cells, which merely extend their processes onto adjacent acini (Dewey 1958;Bogart 1971;Garrett & Emmelin 1979;Redman 1994). It was noticed that the period of myoepithelial cell decrease coincides with the weaning period (Redman 1994).…”

Myoepithelium of salivary glands

“…In rat salivary glands ( Figs. 1,3) the reaction product is deposited mainly in MEC, the luminal cytoplasm of intercalated ducts, and blood capillaries (Bogart, 1968;Dewey, 1958;Garrett and Parsons, 1973;Leeson, 1956;Redman and Ball, 1979;Redman et al, 1980;Shear, 1968). In human salivary glands, AkPase activity is present in blood vessels and focally in intercalated and excretory ducts, but absent from MEC, whereas adenosine triphosphatase (ATPase) activity is strong in MEC and very weak in other parenchymal cells (Auger and Harrison, 1982;Cutler et al, 1977;Garrett and Harrison, 1970;Innes and Cutler, 1978).…”

Comparative Histoenzymology of the Salivary Glands

“…An alkaline phosphomonoesterase activity exists in the vascular walls and in basket cells of the parotid glands (Deane, 1947;Silver, 1954;Hill and Bourne, 1954;Dewey, 1958).…”

“…The parotid acini of man and of rat present a high P-glucuronidase activity (Quintarelli and Chauncey, 1959). Their succinodehydrogenase activity is marked, but this activity is even stronger in the excretory ducts (Telkka, et al 1954;Dewey, 1958). Injection of somatotropic hormone (FIGURES 24 and 25) causes a large increase in the succinodehydrogenase activity of the parotid gland of the rat.…”