Temporal and Spatial Distribution of Alkaline Phosphatase Activity in Male Hypogonadic Rat (hgn/hgn) Testis during Postnatal Development.

Abstract

ABSTRACT. In male hypogonadic mutant rat (hgn/hgn), gonocytes degenerate and peritubular cells form multiple layers around seminiferous tubules during early postnatal testicular development. Alkaline phosphatase (AP) activity has been used as not only a tracer for the primordial germ cells (PGCs) but also a histochemical marker for the peritubular myoid cells. In the present study, we examined the localization of AP activity during the postnatal testicular development in the hgn/hgn and phenotypically normal (+/+ or +/hgn) rat. In the normal testis, high AP activity was located in the surface of the PGCs on 3 days of age. As the PGCs differentiated into spermatogonia, the AP activity drastically decreased in intensity on 7 days and was completely lost by 12 days. In the hgn/hgn, the PGCs showing high AP activity occupied the inside of dilated seminiferous tubules on 3 and 7 days of age. The luminal AP activity declined gradually by 18 days and disappeared on 21 days, when the germ cells completely degenerated in the hgn/hgn testis. In the normal, high AP activity emerged in a layer of the peritubular cells surrounding the tubules on 7 days and afterwards, indicating that the peritubular cells were differentiating into myoid cells. In the hgn/hgn, the peritubular cells formed multiple layers around the tubules and showed weak AP activity on 3 to 18 days of age. On 21 days of age, high AP activity emerged in a single layer of the peritubular cells directly attached to the basement membrane in the hgn/hgn. These results indicate that the PGCs showing AP activity kept remained at later stage in the hgn/ hgn and that the single layer of mature myoid cells showing high AP activity appeared much later in the hgn/hgn testis than in normal. -KEY WORDS: alkaline phosphatase, hypogonadism, peritubular myoid cell, primordial germ cell, testicular development.J. Vet. Med. Sci. 60(6): 671-679, 1998 cells, the abnormal cell division of the gonocytes, the degeneration of the gonocytes, and the formation of multiple layers of the peritubular cells around the seminiferous tubules [32]. Alkaline phosphatases (APs) are membranelinked enzymes that hydrolyze orthophosphate monoesters at alkaline pH [4]. In normal murine testis, AP activity is predominantly localized in the gonocytes and the myoid cells [2,11,16,22]. In this study, we examine the temporal and spatial distribution of AP activity in the postnatal hgn/ hgn and normal (+/+ or hgn/hgn) testis to investigate the distribution and development of the hgn/hgn gonocytes and peritubular myoid cells. MATERIALS AND METHODS Animals:Male normal and hgn/hgn rats used in this study were obtained from matings between proven +/hgn males and females derived from the 21st generation of hypogonadic rat (HGN) line maintained in our department [29]. The rats were kept in a conventional animal room, and were fed a mixed grain diet and water ad libitum [31].Preparation of cryosectioned testis samples: The rats were sacrificed on 3, 7, 12, 18, 21, and 40 days after birth by overdose ether. Th...

Differential tissue development during embryogenesis and regeneration in an annelid

“…As ALP is used as a marker molecule for primordial germ cells and embryonic stem cells in vertebrates (Swartz, 1982;Merchant-Larios et al, 1985;MacGregor et al, 1995;Pain et al, 1996;Suzuki et al, 1998;Pera et al, 2000;Saito et al, 2002), special attention was paid in the present study to determining whether ALP is also expressed in E. japonensis germ cells and neoblasts, the putative stem cells that are thought to participate in regeneration of oligochaetes (Randolph, 1891;Christensen, 1964;Herlant-Meewis, 1964). However, no ALP activity was detected in the neoblasts (Fig.…”

“…In some vertebrates, ALP is used as a marker molecule for embryonic stem cells (Pain et al, 1996;Pera et al, 2000;Saito et al, 2002) and primordial germ cells (Swartz, 1982;MerchantLarios et al, 1985;MacGregor et al, 1995;Suzuki et al, 1998); in E. japonensis, however, no ALP activity was detected in the neoblasts (Fig. 2L), the putative stem cells that are thought to participate in regeneration of oligochaetes (Randolph, 1891;Christensen, 1964;Herlant-Meewis, 1964).…”

Primordial Germ Cells (Spermatogonial Stem Cells) of Bullfrogs Express Sex Hormone-Binding Globulin and Steroid Receptors during Seasonal Spermatogenesis

“…Alkaline phosphatase (AP) has been used as a stem cell marker for PGCs/gonocytes in mammal embryos and newborns [Suzuki et al, 1998;Kakegawa et al, 2008]. In rats aged 3 days, a high AP activity was detected in the membrane of PGCs (gonocytes) located in the central region of the seminiferous tubules [Suzuki et al, 1998].…”

Fine Mapping of the Region Including Hypogonadism (hgn) Locus on Rat Chromosome 10

“…Testicular pathogenesis begins in the fetal period and progresses during postnatal testicular development [20]. Most germ cells degenerate in the testes before entering meiosis because of Sertoli cell dysfunction [13,17]. hgn/hgn males show not only hypogonadism but also bilateral hypoplastic kidney (HPK) [19].…”