ULTRASTRUCTURE OF LIPID-CONTAINING CELLS OF THE ANTERIOR-PITUITARY GLAND OF THE DOMESTIC CHICKEN, GALLUS-DOMESTICUS

A combination of light and electron microscopy techniques was applied to characterize a luteinizing hormone (LH)-gonadotroph-like cell in th e anterior pituitary gland of the adult domestic chicken. This cell ty pe (mean +/- sem, 91 +/- 8 mu m(2)) was larger than typical LH-gonadot rophs (71 +/- 5 mu m(2), P < 0.01) and seen in pituitary glands from a dult males but not those from adult females of the same age. The ultra structural features of these cells were similar to typical LH-gonadotr ophs in the same section, except for the presence of large (1,126 +/- 77 nm diameter), round, or polymorphic electron-dense inclusions (14 /- 3 per cell) in the cisternae of the endoplasmic reticulum. When res in sections of anterior pituitary gland were stained with the vapours from the fixative osmium tetroxide and a solution of potassium ferricy anide, inclusions were found that appeared to be lipid in nature and w ere circumscribed by the cisternal membranes of the endoplasmic reticu lum. These lipid inclusions were associated occasionally with acid pho sphatase and lysosome-like bodies. The cellular pigment, lipofuscin, c onsidered to be a marker of aging, was absent from the anterior pituit ary glands from these adult chickens. These observations suggest that the appearance of lipid in LH-gonadotrophs is unlikely to be age-relat ed and an alternative explanation is discussed in relation to a sex di fference in the LH response of adult chickens to gonadotrophin-releasi ng hormone (GnRH). (C) 1993 Wiley-Liss, Inc.