A morphological and endocrinological study of the male reproductive system of the thicktailed bush baby (galago garnetti)

Abstract

Eight male thick-tailed bush babies, Ga/ago garnetti, were used in this study. Blood samples were obtained twice a week from each animal, for a period of eight weeks. Serum obtained from each sample was utilized in the determination of testosterone (T) and luteinizing hormone (LH) using radioimmunoassay and Leydig cell bioassay respectively. There was significantly higher (p-cO .05) mean serum T levels In the morning compared to evening hours. lack of a definite rhythm of LH secretion during daytime, no significant correlation between mean serum T and LH. and no significant correlation between animal body weights and mean Tvlevels during daytime. Morphology of the reproductive system in this species was studied. The gross structure was similar to those of related species and othe~man primates. Spermatogenesis was-st~uSing normal microscopy techniques. Using semithin sections. twelve stages of the seminiferous epithelial cycle, and seventeen steps of spermatid development were identified. Stages I-IV of the cycle was characterized by two generations of spermatids and one of sperrnatocytes. Stage VI had a single generation of both spermatocytes and spermatids. Stages VII-XII had a single generation of spermatids and two of spermatocytes. Spermiation in this species preceded the appearance of preleptotene spermatocytes in the germinal epithelium. Comparisons of the frequencies of the stages of the seminiferous epithelial cycle in this species with other mammals revealed, significantly close correlation (p<O.05) between data obtained in this species and those of two rodents and a monkey, and conversely disparity with those of man and the baboon. Fine structural examination of spermiogenesis III this species focused on topographical relationships of the chromatoid body and Golgi apparatus to the proacrosomal granules, acrosome, nucleus and tail. It is proposed that the ch ro mato id body may have an in teg ral ro Ie III early acrosomal development. Leydig cells and the basal cells of the vas deferens in this species, exhibited unusual cytoplasmic crystalloid inclusions. The lining of the excurrent duct system was characterized by presence of principal and basal cells. The principal' cells had features of absorptive and synthetic activity whose intensity varied along the duct. Basal cells however, did not show any significant variation along the duct system. Based on histological and fine structural appearance, the epididymis in this species was divided into six zones or regions. The morphology of the cells along the excurrent ducts resembled those In other mammalian species. Three types of accessory sex glands namely, prostate, vesicular and bulbourethral glands were evident. Fine structural examination revealed possible differences In secretory mechanisms in the three glands.