The pituitary gland of the musk shrew, Suncus murinus L. (insectivora), with special reference to the cytology of the adenohypophysis

Abstract

The pituitary gland of the musk shrew, Suncus murinus L. was studied with special reference to the cytology of the adenohypophysis. In addition to the agranular cells (chromophobes ), seven morphologically and tinctorially distinct Nchromophilic cell types (four mucoid and three acidophilic) were observed in the pars anterior. These cells have been tentatively named as types one to seven. On the basis of their morphology, topography and staining reactions, cells of types one to six were compared, respectively, with the TSH, FSH, ICSH (L,H), LTH (prolactin), STH and ACTH cells of other mammals. The identity of type 7 cells could not be determined. Although mucoid cells (types 1, 2) art: more concentrated in the rostroventral region of the pars anterior, a definite "zona tuberalis" seems to be lacking. Since the musk shrew is not a seasonal breeder, the gonadotropic cells (types 2, 3 ) of the adenohypophysis do not seem to fluctuate in structure during the different times of the year. However, conspicuous hypertrophy, hyperplasia and intense secretory activity of type 4 cells during pregnancy and lactation reinforces the postulation that these cells are lactotropic in function. Follicular cysts and colloid in the residual cleft were observed in a few instances. Their possible origin and significance are discussed.Knowledge cif the morphology and cytology of the hypophysis in several groups of mammals has been enriched immensely i n recent years. (Purves, '61, '66; Herlant, '64, '65; Hansi:rom, '66; Girod, '66; Allanson and Parkes, '66). However, only scanty inform ation is available on the order Insectivora, except for the mole (Herlant, '64; Holmes, '66), desman (Herlant, '64) and hedgehog (e.g., Girod et al., '66, '67). The family Soricidae of this order does not seem to have received any attention, the (only study having been confined to brief description of the hypophysis of the short-tailed shrew, Blarina (Dawson, '63; Hanstrom, '66). The present paper presents a detailed anatomical description of the hypophysis and a comprehensive account on the cytology of the adenohypophysis of the musk shrew, Suncus ,murinus L. Banaras Hindu University c a m m s and adjacent areas were used. Included were 50 females in different stages of gestation, 12 pregnant and concurrently lactating females, 8 lactating females, 90 non-pregnant females and nearly 100 males. Most of the animals were sacrificed within 12 hours of capture; some were maintained in the laboratory for varying periods before sacrifice. Conspicuous seminiferous tubules visible through the tunica albuginea of the testes, and the presence of spermatozoa in the testes and the genital tract, were taken as indicators of sexual maturity in the male. Since some animals weighing 28-35 gm were pregnant, females weighing 40 gm or more were regarded as being sexually mature. The condition of the mammary glands, uteri and ovaries were considered in assessing the sexual maturity of the female. Pregnant females were classified into three groups (those of early, ...

Functional Significance of the Cells in the Pars Anterior of the Pituitary Gland of the Musk Shrew (Suncus Murinus L.)

“…The literature on this subject has been extensively reviewed (Purves, 1966;Baker, 1974;Girod, 1976), but there is little information concerning the cytology of the insectivore pituitary gland (Hanström, 1966), with the exception of the mole (Herlant, 1964;Holmes, 1966), desman (Herlant, 1964) and hedgehog (Girod, 1976). Earlier investiga¬ tions on the Soricidae are confined to brief anatomical descriptions of the hypophyses of the short-tailed shrew (Blarina brevicauda: see Naik & Dominic, 1972) and the EuroAsiatic shrew (Sorex araneus: Hanström, 1966). The cytology of the musk shrew (Suncus murinus L.) adenohypophysis has also been described (Naik & Dominic, 1972).…”

“…Earlier investiga¬ tions on the Soricidae are confined to brief anatomical descriptions of the hypophyses of the short-tailed shrew (Blarina brevicauda: see Naik & Dominic, 1972) and the EuroAsiatic shrew (Sorex araneus: Hanström, 1966). The cytology of the musk shrew (Suncus murinus L.) adenohypophysis has also been described (Naik & Dominic, 1972). The present report deals with the functional significance of the adenohypophysial cells in this species.…”

Three-dimensional distribution patterns of PRL, GH and ACTH cells in the house musk shrew (Suncus murinus)

“…Naik and Dominic (1972) distinguished seven tinctorially distinct cell types in wild shrews and drew schematic distribution maps. Later, they determined the functions of six cell types on the basis of the cellular responses to various experimental stimuli: thyroidectomy, gonadectomy, adrenalectomy, and administration of androgen, gonadotrophin, prolactin, L-thyroxine, or estrogen (Naik and Dominic 1978).…”

“…We chose pituitary glands of the house musk shrew, Suncus murinus, order Insectivora, for our 3D study because of their small size and distinct cell distribution patterns, as shown by Naik and Dominic (1972) in wild musk shrews. The house musk shrew was domesticated in Japan as an experimental animal (Oda and Kondo 1977).…”

Cell Types of the Pars distalis of the Hedgehog (<i>Erinaceus europaeus</i> L.) Adenohypophysis: Cytological, Immunocytochemical and Ultrastructural Studies. II.

“…Concerning PRL cells, we emphasize the particularity of the formation of newly synthesized granules in the Golgi area; such a process was not reported in other species. Except for this ultrastuctural characteristic, PRL cells of the hedgehog look like PRL cells individualized in other Insectivora either at the level of photonic microscopy or in electron microscopy [Her lant and Klastersky, 1961;Herlant, 1964, in Talpa europaea;Naik and Dominic, 1972, in Suncus murinus (type IV of the chromophilic cells)]. Hanstrom [1946] and Bloom [1960] have described two types of 'acidophils' in the hedgehog pars distalis but they have not clearly defined their func tional significance.…”