Effects of Exposure of Lactating Female Rats to Polychlorinated Biphenyls(PCBs) on Testis Weight, Sperm Production and Sertoli Cell Numbers in the Adult Male Offspring.

Abstract

ABSTRACT. To investigate the effects of intermittent and continuous exposure of lactating rats to Aroclor 1242 (a PCB congener), testis weight, daily sperm production (DSP) and Sertoli cell number per testis were examined in the adult male offspring. Thyroxine (T 4 ) was also measured because of the well-documented effects of polychlorinated biphenyls (PCBs) on this hormone. In experiment I, 3 groups of lactating female rats received daily subcutaneous injections of low (0.8 mg) or high (1.6 mg) doses of Aroclor 1242 in 0.1 ml corn oil from parturition to weaning of pups at 21 days. In experiment II, 3 groups of lactating rats received 2 subcutaneous injections per week of 0.8 or 1.6 mg Aroclor 1242, as in experiment I. In both experiments, control rats received vehicle alone. Serum T 4 was measured at 21 and 90 days of age, and testis weight, DSP and Sertoli cell numbers were examined at 90 days. In experiment I (continuous exposure), both the low (0.8 mg) and high (1.6 mg) doses suppressed T 4 concentrations at 21 days of age. Testis weight was increased by 14.8% (LD) and 16.5% (HD) compared with controls. DSP was increased by 20.4% in the low dose and 25% in the high dose animals compared with controls. The number of Sertoli cells per testis was increased by 32.6 and 39.4% in low and high dose animals, respectively. A similar study in which the lactating females were only dosed twice per week (experiment II) did not show any differences in these parameters. These results indicate that continuous exposure of lactating female rats to PCBs increases testis weight, sperm production and Sertoli cell numbers in the adult male offspring.

Sexual differentiation of the rodent hypothalamus: Hormonal and environmental influences

“…The detrimental impact of PCBs on the neuro-endocrine system development is due to their ability to interact with the mechanism of action of many hormones, including sex steroids. PCB are able to affect steroid production [42,43], to modulate the expression of their receptors [44], as well as to interfere with hormonal steroid receptor binding either as agonists or antagonists, depending on the structure, type of receptor and target organ [45,46]. Many coplanar PCBs have also a dioxin-like activity, interacting with the aryl hydrocarbon receptor (AhR) [47].…”

Morphometric Studies on the Testis of Korean Ring-necked Pheasant (Phasianus colchicus karpowi) during the Breeding and Non-breeding Seasons

“…One testis from each animal was removed, freed from epididymis and weighed (this was recorded as the fresh testicular weight). The speci¢c gravity of each of these testes was determined by £otation in a series of sucrose solutions of known speci¢c gravity as described previously (Ariyaratne and Mendis-Handagama, 2000;Kim, 2001;Kim et al, , 2002. The ipsilateral testis (n = 8 pheasants per month) was ¢xed by a vascular perfusion technique as described previously (Ariyaratne and Mendis-Handagama, 2000;Kim, 2001;Kim et al, , 2002.…”

“…Testis ¢xation was completed within 45^60 min; the ¢xed testis was weighed, the speci¢c gravity was measured and the ¢xed testis volume was calculated. The ¢xed testis was cut into approximately 2 mm cubes and processed for stereology as described previously (Ariyaratne and Mendis-Handagama, 2000;Kim, 2001;Kim et al, , 2002. The testis volume was determined by dividing the testis weight by its density (density = speci¢c gravity in metric units).…”

“…The sections were stained with methylene blue azure II. Various components of testicular parenchyma and the di¡erent cell types in the interstitium were identi¢ed under a Leica DMRBE microscope (Germany) as described previously (Ariyaratne and Mendis-Handagama, 2000;Kim, 2001;Kim et al, 2001Kim et al, , 2002. The volume density of testicular components (de¢ned as the volume of a component per unit volume of testis tissue) was determined by a point counting method (Weibel, 1969) using an ocular grid with 121 test points ¢tted to a 610 ocular lens of the microscope.…”

Beeinflussung testikulärer Zellen durch endokrin aktive Umweltchemikalien

“…Werden säugende Ratten kontinuierlich Aroclor 1242 ausgesetzt,zeigen die männ-liche Nachkommen im Erwachsenenalter ein erhöhtes Testisgewicht, eine erhöhte tägliche Spermienproduktion und eine erhöhte Sertolizellzahl pro Testis [15]. Die Exposition von männlichen Mäusen gegenüber Arochlor 1242 (0, 10, 25, 50 und 100 mg/kg KG),pränatal und während der Laktationsphase, führte im frühen Erwachsenenalter (16 Wochen alt) zur signifikanten Erhöhung der Motilität epidydimaler Spermatozoen und der Spermatozoendichte, wobei das Testisgewicht im Vergleich zur Kontrolle unverändert war.…”