We report for the first time a possible association between mutations in dynein genes and isolated AZS. Male carriers of the mutations always exhibit AZS, whereas female carriers manifest no alterations in either fertility or pulmonary clearance.

The relationship between thyroid function and testicular development in the rat was investigated. Hypothyroidism was induced during fetal or post-natal life by adding methimazole (MMI) to the drinking water of pregnant or lactating mothers. A group of newborn rats was treated with MMI and i.p. injections of L-tri-iodothyronine (L-T3). Hypothyroidism was shown by the reduced serum levels of total T3 and of total thyroxine (T4) in pregnant mothers and in pubertal rats. Testes were studied using light microscopy at 18 and 21 days post coitum or during puberty (21, 35 and 50 days after birth); serum levels of gonadotrophins were also evaluated in pubertal rats. Hypothyroidism had no effect on testicular development during fetal life and when induced in newborn rats it was associated at puberty with reduced serum levels of FSH and LH and with delayed maturation of the testis compared with control rats. The delay in maturation consisted of a reduction in the diameter of seminiferous tubules, and a reduction in the number of germ cells per tubule; this was associated with increased degeneration and arrested maturation of germ cells. In addition, Sertoli cells demonstrated retarded development, as indicated by a delay in the appearance of cytoplasmic lipids and in the development of a tubule lumen. Hormonal and morphological abnormalities were absent in rats treated with MMI plus L-T3. In conclusion, hypothyroidism occurring soon after birth caused reduced levels of gonadotrophins in the serum and a delay in pubertal spermatogenesis, possibly due to retarded differentiation of the Sertoli cells.

No abstract

Degeneration of human male germ cells was analysed by means of light (LM) and transmission electron (TEM) microscopy. The frequency of degenerating cells was correlated with that of Fas-expressing germ cells in human testes with normal spermatogenesis (n = 10), complete early maturation arrest (EMA) (n = 10) or incomplete late maturation arrest (LMA; n = 10) of spermatogenesis. LM analysis of testis sections with normal spermatogenesis indicated that degenerating germ cells were localized in the adluminal compartment of the seminiferous epithelium. TEM showed that apoptotic cells were mostly primary spermatocytes and, to a lesser extent, round or early elongating spermatids. Apoptotic germ cells appeared to be eliminated either in the seminiferous lumen or by Sertoli cell phagocytosis. An increased number of degenerating cells was observed in testes with LMA as compared with normal testes and testes with EMA of spermatogenesis (P < 0.001, Wilcoxon's rank sum test). Comparison of these results with those obtained from immunohistochemistry experiments demonstrated a tight correlation between the number of apoptotic cells and the number of Fas-expressing germ cells (P = 0.001, Spearman's rank = 0.69). These findings suggest that altered meiotic and post-meiotic germ cell maturation might be associated with an up-regulation of Fas gene expression capable of triggering apoptotic elimination of defective germ cells.

The distribution and relative density of peptide-containing nerves was studied in the rat in order to assess the progression of neuronal changes during the postnatal development of the male genital system from the prepubertal age to adulthood. Testis, caput and cauda epididymis, ductus deferens, seminal vesicles, prostate and penis from 8-, 20-, 38-, and 70-day-old rats were sectioned and were immunostained with antisera to the neuropeptides calcitonin gene-related peptide (CGRP), vasoactive intestinal peptide (VIP) and neuropeptide Y (NPY), and to a general neuronal marker, protein gene product 9.5 (PGP 9.5). The testicular parenchyma and caput epididymis did not show any immunoreactivity. Very scattered CGRP-containing nerves were present in 8-day-old rats; numerous VIP-, CGRP-, and NPY-peptide-containing nerves were observed in the cauda epididymis, ductus deferens, accessory glands and penis of 20-day-old rats. The number of nerves increased in 35-day-old rats while no changes were observed in more adult rats. A parallel increase was seen for the immunostain for PGP 9.5. These data suggest that peptide-containing nerves appear in the genital system after birth and reach a full development before the completion of puberty. Peptide-containing nerves were visible first in the interstitial area and then spread in the muscular coat of the ducts, glands and of the blood vessels. While CGRP- and NPY-containing nerves were distributed in the vicinity of the muscle cells, VIP-containing nerves were also observed in the subepithelial regions, suggesting a possible role of this neuropeptide in the control of epithelial functions.