Cholinesterase activity in the harderian gland of anas domesticus

Abstract

The histochemical localization and quantitative levels of acetylcholinesterase and butyrylcholinesterase have been determined in the Harderian glands of normal ducks and ducks fed with salt to increase their serum sodium concentrations;there was no significant difference between the two groups.Acetylcholinesterase was present at a mean concentration of 68.2 pM/gm/hour (range 65.5 -72.7 pM/gm/hour) in the normal Sniraals and 67.6 pM/gm/hour (range 63.8-76.4pM/gm/hour) in the salt-fed gruup; the enzyme was present in nerves related to blood vessels. Butyrylcholinesterase was present at a mean concentration of 42.5 pM/gm/hour (range 20.4 -58.7 pM/gm/hour) in the control animals and 40.2 pM/gm/hour (range 29.3 -61.3 pM/gm/hour) in the salt-fed group; the enzyme was present in epithelial cells and in nerves related to blood vessels similar to those containing acetylcholinesterase. There was a close correlation between the subjective assessment of cholinesterase activity based on histochemical techniques and the amount quantitatively measured. The gland probably secretes mucus and lipids; the epithelial butyrylcholinesterase may play a role in lipid metabolism in the tissue. The nerves may regulate the flow of blood through the gland.

The avian Harderian gland: Morphology and immunology

“…The absence of mitotic activity in the secretory epithelia suggests that holocrine secretion is unlikely (Burns, 1974). Secretion in the fowl Harderian gland (type I gland) is also considered to be merocrine (Wight et al, 1971a), while in the duck (type I1 gland), it is also considered to be merocrine by Fourman and Ballantyne (1967) and by Kiihnel and Beier (1973), though Brobby (1972) thought it to be holocrine in this species. Type I11 glands also appear to be merocrine (Burns, 1975 b) .…”

“…Stammer (1964) and Fourman and Ballantyne (1967) demonstrated that acetylcholinesterase (AchE) is present in fibers which are related to blood vessels in the interlobular septa and in connective tissues surrounding some of the collecting ducts Both groups suggested that cholinergic fibers may regulate blood flow thoughout the gland in birds.…”

Plasma cells in the avian Harderian gland and the morphology of the gland in the rook

“…The absence of mitotic activity in the secretory epithelia suggests that holocrine secretion is unlikely. Secretion in the fowl Harderian gland is merocrine and in anatids it is also considered to be merocrine by Fourman and Ballantyne (1967) and by Kiihnel and Beier (1973), though Brobby (1972) thought it was holocrine in the duck. With the advent of the electron microscope the distinction between apocrine and merocrine secretion has become blurred (Bloom and Fawcett 1968), and debris in the tubule lumina of avian Harderian glands may well be part of a merocrine-apocrine form of secretion.…”